2021-Q3 IS-MPMI Interactions Issue 1 (copy)
Dr. Valerie M. Williamson, professor emeritus at UC Davis, in the Department of Plant Pathology, was recently interviewed by Ani Chouldjian and Jennifer D. Lewis concerning her career at UC Davis and her studies on the Mi gene. The Mi gene is found in tomato and confers resistance to root-knot nematodes, such as Meloidogyne incognita, which infect thousands of crops worldwide.
Also in this issue...
In recognition of her contributions to the scientific community as an educator, mentor, and researcher, Dr. Barbara Kunkel was named a 2020 AAAS Fellow. Yeram Hong and Jennifer D. Lewis interviewed Dr. Kunkel about her career, female role models in science, and diversity and inclusion in the scientific community.
Dr. Jan Leach is the 2020 recipient of the APS Award of Distinction. This honor is presented to persons who have made exceptional contributions to plant pathology. Dr. Kamal Kumar Malukani recently interviewed Dr. Leach to learn more about the qualities needed to become a leader in plant pathology.
Dr. Pamela Ronald was recently awarded the 2020 World Agriculture Prize for her achievements in agricultural research and science education. Nick Colaianni interviewed Dr. Ronald to learn more about her accomplishments, the challenges faced in food production, and how science is being used to address these issues.
Kelley Clark and co-authors demonstrate the effect the SDE1 protein from the citrus greening (huanglongbing) pathogen can have on plants. Their results show that the effector is an important virulence factor that induces premature senescence-like responses in both Arabidopsis and citrus host plants.
IS-MPMIConnect, the society’s exciting new virtual discussion space, hosted two events in February. The symposium held on February 17 focused on Mental Health and Dealing with Failure and the event on February 24 featured conversations with Dr. Morgan Halane.
Join IS-MPMIConnect on March 29 for the complimentary LGBTQ+ Webinar, where scientists at various stages in their professions will share their experiences with inequality and bias in STEM. Register today!
Join IS-MPMIConnect on April 14 for a conversation with scientists who are successful academics with disabilities at various stages in their careers. Register today!
Focus Issue Editors Jacquie Bede, Kenichi Tsuda, and Jeanne Harris are inviting research and review articles that explore the complex interactions between plants, microbes, and the abiotic environment. Articles highlighting translational research, as well as fundamental understanding, are welcome. Learn more about this focus issue.
There are currently 11 What’s New in MPMI! virtual seminars available for viewing. Coming up next, Kenichi Tsuda will discuss Top 10 Question #5: Does ETI potentiate and restore PTI—or is there really a binary distinction between ETI and PTI? Register today!
Diversity and inclusion are core values of the International Society of Molecular Plant-Microbe Interactions. As an international society, it is our priority to increase diversity and facilitate change.
To draw our community together, IS-MPMI gathered virtually for the second of two workshops titled Taking MPMI Discoveries to the Field. These workshops highlighted efforts to translate molecular discoveries to the field and address MPMI Top 10 Question #3: How can we translate basic research into emerging crop plants?
IS-MPMI is excited to announce the 2021 Congress: eSymposia Series, which will take place online with a series of three separate events starting this summer! Abstract submissions open later in March. Stay tuned for more details about this opportunity to share your research and network with colleagues at this virtual scientific event.
Take the IS-MPMI Congress Series Survey
We are always looking for content for Interactions. Please contact Interactions Editor-in-Chief Dennis Halterman with questions or article ideas.
Ani Chouldjian and Jennifer D. Lewis
is currently a senior at the University of California,
Berkeley, majoring in microbial biology. She is interested in plant–microbe interactions,
infectious diseases, and genetics. After graduation she wishes to take a year or
two off from school to pursue research opportunities and later enter a microbiology
and immunology Ph.D. program.
Lewis is a principal investigator
at the U.S. Department of Agriculture and an adjunct associate professor at UC Berkeley.
Her lab studies the plant immune system and its response to the bacterial pathogen
The Lewis lab is committed to diversifying plant sciences. To encourage this, they
are performing interviews with prominent scientists in the field to discuss their
research and their perspectives on diversifying science.
Dr. Valerie M. Williamson
M. Williamson is a professor emeritus
at UC Davis in the Department of Plant Pathology. Throughout her career at UC Davis,
she has studied the Mi
gene, a gene found in tomato, which confers resistance to root-knot nematodes, such
as Meloidogyne incognita.
infects thousands of crops and forms biotrophic interactions with host roots. These
nematodes establish feeding sites on tomato plant roots and release chemicals that
induce nuclear division of root cells without cytokinesis, leading to the formation
of enlarged cells called galls. The Mi gene, like other resistance genes, has conserved
leucine-rich repeat (LRR), leucine zipper (LZ), and nucleotide binding-site (NBS)
domains, which allow for pathogen recognition and signal transduction; therefore,
tomato plants that have this gene are resistant to root-knot nematodes.
Dr. Williamson’s greatest scientific achievement
was cloning the Mi
gene, which allowed for its insertion into plants that are susceptible to root-knot
nematode infection. This gene was discovered in a wild tomato plant and had other
“bad” genes associated with it. Cloning the gene allowed Dr. Williamson’s lab to
insert the Mi
gene, alone, into other plant genomes to see it could confer resistance to nematodes.
When asked why she thinks her research is important for the future, Dr. Williamson
root knot nematode is all over the world, every continent has it, except Antarctica;
it’s a huge problem in agriculture everywhere, and the way it’s controlled is with
pesticides. And, they’re nasty pesticides, and there is a need to come up with new
control measures. So, modifying [plants] with the Mi gene would be another control. Another
project that I’ve been working on for the past 10 years is trying to figure out
what attracts nematodes to roots. If you could understand what attracted them to
roots and repel them, or trap them so that they are not attracted to roots anymore,
that would be another way of controlling them.
Dr. Williamson’s discovery and cloning of the Mi gene was monumental;
however it took some time for her to find what she is truly passionate about. Dr.
Williamson grew up in a town in New Hampshire and had never planned to become a
plant pathologist. Instead, her plan had been to become a medical technician. She
said, “I was assuming that I would probably do some kind of medical technician type
of work, because that’s the only thing I knew about that would be a good career.
I loved biology, and I had always loved biology.”
As a first-generation college student, she attended
Northeastern University for her undergraduate education, where she participated
in a cooperative education program. The program encompassed six months of schooling
and six months of clinical experience that focused on blood research. However, this
type of research did not interest her. She said, “I did some karyotyping of human
chromosomes, drawing blood, and analyzing blood—but I didn’t really like that.”
While looking for other research opportunities
during her undergraduate education, Dr. Williamson was discouraged at times from
pursuing a career in science and faced gender-based discrimination. She said, “Yes,
there have been discouraging things. When I was an undergraduate and was doing these
research stints in different places, there was one place I went to. They said that
they had never had a woman before, and if they hired me, they would have to put
in a new restroom.”
Although she was discouraged at times, Dr. Williamson
did not give up. After graduation, she married a man in the army and moved to Alaska
with him, where she obtained a job at the University of Alaska’s Institute of Marine
Science. There she did research on trace metal contaminants of sea water; however,
she was more interested in the biological samples that her colleagues were collecting.
She said, “The people around me were collecting biological samples, and I thought
that was much more interesting. I was frustrated because I was really interested
in science, but I couldn’t do what I wanted to do. When you’re a technician, you
can’t do what you want to do. You have to do what you’re assigned.”
Wanting to learn more about research, Dr. Williamson
applied and was accepted into a biochemistry graduate program at UC Davis. Her thesis
work was on RNA polymerase in Bacillus subtilis, and she received her Ph.D. degree in biochemistry
in 1978. After obtaining her Ph.D. degree, Dr. Williamson became a postdoctoral
fellow at the University of Washington in Seattle, where she worked on alcohol dehydrogenase
in yeast. She said, “I got excited about alcohol dehydrogenase, so I cloned the
gene that encodes it, which turned out to be very useful.” Alcohol dehydrogenase
is an enzyme that converts acetaldehyde into ethanol during glucose fermentation
in yeast. It is used in industry to reduce ketones into chiral alcohols.
After completing her postdoc, Dr. Williamson accepted
a job in Dublin, CA, at a company called Arco Plant Cell Research Institute. During
this time, oil was scarce due to the Cold War, and a lot of effort was being put
into biofuel production. While there, she continued studying yeast and alcohol dehydrogenase,
because the company was interested in fermentation. While working at Arco Plant
Cell Research Institute, Dr. Williamson noticed that her colleagues were working
on plants, and so she decided to start a project on plants as well. She said, “The
other people hired there were doing research on plants, so I decided to start a
project on plants. I started looking into what I would like to do. I knew that I
liked nematodes, because I had met some C. elegans researchers in Seattle, and I looked
into plant pathogens and thought I want to do something on plant–pathogen interactions.”
However, when oil prices lowered, the company decided not to pursue agricultural
research anymore. The company was sold, and at the same time, a position opened
up in the Department of Nematology at UC Davis.
At the time, Dr. Williamson was not confident in
her abilities to become a faculty member. She said, “I did not plan on being a faculty
member. I thought that was something that I could not handle. There weren’t many
role models of women being successful in it. They were mostly men then.” However,
when Dr. Williamson applied for the UC Davis faculty position, she got the job.
When she started working at UC Davis, Dr. Williamson
did feel the pressure of being one of the only women in a faculty position. She
said, “When I first started at UC Davis, a lot of the committees I would get put
on I would be the only woman there. I would be stuck onto all these committees because
they wanted to have a woman there. That’s kind of hard on the woman or minority
to be the only one, and you also get stuck with a lot of stuff.” Times did improve,
however; Dr. Williamson persevered and found what she was most passionate about.
She has been doing research as a UC Davis faculty member on the Mi gene and root-knot
nematodes ever since.
When asked if she sees growth in the inclusion
of women and minorities in STEM, she said,
improved enormously since I started, and I think the women are holding their own
really well. It’s not like we had to put them there so that we could have more women.
We have a better proportion [of women]. They are really making major contributions
and that helps too, because then you get more [women] in. They see that women can
do this, and they can do a really good job in this.
are a lot of young people who don’t realize that [research] is a career option,
and for them to see it, they need to be given chances in high school or early undergrad
[courses] to just see what science is.
have been harder to get in science. Maybe they are still at the stage where they
need to be exposed more. Interacting with high-school teachers is a good way [and]
having summer programs where they come in and look at labs and hang around the labs.
It’s really good to have undergraduates in the lab, especially [students] who have
not been exposed to science and have these programs where they come in and make
friends with people who have been more exposed to science.
Although Dr. Williamson is now retired, she continues
to perform research. Mi
gene-resistant nematodes have been found throughout California; therefore, Dr.
Williamson is initiating efforts to find differences between resistant and nonresistant
nematodes through comparison of their genomes.
In her free time, Dr. Williamson likes to travel,
be outside, and hike along the coast at Point Reyes and Bodega Bay. She also likes
to garden because she can “look at [her] plants and think about their diseases.”
row (left to right): Ilea Chau, Jamie Calma, Yuritzy Rodriguez, Yuan Chen, Karl
Schreiber. Back row (left to right): Jana Hassan, Hunter Thornton, Jennifer
Lewis, Maël Baudin, Jacob Carroll-Johnson, Jack Kim.
Dr. Barbara Kunkel
Yeram Hong and Jennifer D. Lewis
Yeram Hong is an undergraduate student at UC Berkeley in her third year. She
is double majoring in forestry and genetics and plant biology. From a young
age, Yeram was interested in the natural environment, with a particular
interest in plant biology. Her current research interests include protein
function in plant nuclear membranes and bacterial plant pathology. Outside of
academia, Yeram enjoys drawing, caring for her many houseplants, and reading
Jennifer Lewis is a principal investigator at
the U.S. Department of Agriculture and an adjunct associate professor at UC
Berkeley. Her lab studies the plant immune system and its response to the
bacterial pathogen Pseudomonas
syringae. The Lewis lab is committed to diversifying plant sciences.
To encourage this, they are performing interviews with prominent scientists in
the field to discuss their research and their perspectives on diversifying
Dr. Barbara Kunkel
Dr. Barbara Kunkel is a professor at Washington
University in the Department of Biology, where she leads a research group and
teaches courses in general and plant biology. Her lab is interested in the
complex biological communication between bacterial plant pathogens and their
hosts, as well as the bacteria’s virulence mechanisms. Her research group takes
a genetic and molecular approach in looking at both bacteria and their plant
hosts to develop a more clear and integrative view of disease. Currently, Dr.
Kunkel is interested in investigating the molecular mechanisms of disease
caused by Pseudomonas syringae in Arabidopsis
thaliana. More specifically, she works to understand how auxin, a
plant growth hormone, may play a role in these plant–bacteria interactions. She
is particularly interested in understanding how bacteria sense auxin and
respond to it and the significance of this interaction. Prof. Kunkel’s research
is important in obtaining a fundamental understanding of the virulence
strategies pathogens use. This knowledge can be used in the future to develop
breeding, cultivation, and control strategies to address the global issues of
crop failure and agricultural pathogen outbreaks. By providing fundamental
knowledge about the interactions between bacterial pathogens and plants, she
believes that her discoveries may be crucial to developing novel biological
technologies to address crop losses from disease.
One of her major discoveries was
the identification of the coronatine virulence factor as a jasmonic acid mimic
in the Arabidopsis–Pseudomonas pathogenic interaction. Her lab stumbled upon CORONATINE INSENSITIVE 1 (COI1),
a gene that encodes the coronatine receptor, while examining plant mutants that
were particularly resistant to bacterial infection. At the same time, another
researcher in her lab, who was focused on the bacterial side, isolated several
mutants in a biosynthetic gene cluster in P. syringae that
coded for coronatine. Connecting these observations, her lab realized
coronatine was particularly significant. Although coronatine had been
previously identified, her lab was able to find their “first indication that
manipulation of plant hormone biology [aside from purely defense hormones] was
important in these pathogen interactions.” They had discovered a virulence
factor that the pathogen used as a hormone mimic to modulate the biology of its
To recognize her considerable and
valuable contributions to the scientific community as an educator, mentor, and
researcher, Dr. Kunkel was awarded the AAAS Fellowship as one of the elected
Fellows of 2020. In response, Dr. Kunkel commented: “I was surprised to tell
you the truth…but I was also very thrilled [as] it gives me some exposure that
I would not have had otherwise.” This opportunity allows people to learn about
her research and become more interested in the topics that she is researching.
Through her achievement, she is paving the way in science as a role model for
future women scientists to look up to and have the conviction that success is
Despite her research successes,
she had not originally planned on entering this career path. From a young age,
Dr. Kunkel had a love for horses and other large animals and dreamed of
becoming a veterinarian. Following her dreams, she attended the University of
California, Davis. There, she became drawn to the pastoral life of working in
the agricultural sector and began studying agricultural sciences. However, this
was not meant to be, as she stated, “it was unrealistic because I’m not a farm
kid, I’m a city kid.” In her second year of college, Dr. Kunkel found her true
passion in a genetics course taught by Dr. Francisco Ayala. She became a genetics
major, specializing in plant biology and bacteriology.
After graduating from UC Davis,
Dr. Kunkel was unsure about her next steps. However, she loved to learn and was
just being introduced to the world of scientific experimentation; graduate
school seemed like the next step. Interested in symbiotic relationships, she
looked for a graduate school where she could study plant–microbe interactions.
Although she was not able to find the right opportunity in this line of
interest, she obtained her Ph.D. degree at Harvard studying gene expression in Bacillus subtilis in Dr. Richard Losick’s Lab. For her postdoc, Dr.
Kunkel decided to pursue research in the area of plant–pathogen interactions
because she wanted to work with plants again and she “wanted to study a system
where you could do the bacterial part and the plant host was genetically
tractable.” She completed her postdoc at the University of California,
Berkeley, with Dr.
Brian Staskawicz, studying disease resistance in plants using a genetics
approach to investigate which genes control the ability of a plant to detect
the pathogen and activate defense responses.
Although Dr. Kunkel had never
planned on becoming a university professor, she realized while obtaining her
Ph.D. degree and completing her postdoc that she loved the scientific process.
During her postdoc, Dr. Kunkel decided she wanted to run her own lab. While she
was working in the Staskawicz lab researching disease resistance, she continued
to wonder, “What’s the pathogen’s part in this?” She began planning to start a
lab that would also study the pathogen as well as the plant host. At this time,
researchers had discovered the type III secretion system (T3SS) in bacteria.
Using this system, bacteria can inject into their plant hosts proteins that
directly affect plant physiology and make the plant more susceptible to
infection. Fascinated by the recent discovery of the T3SS, Dr. Kunkel decided
that one of her first projects would be to study virulence mechanisms in P. syringae and find out more about the proteins being
As a woman in science, Dr. Kunkel
wondered if she could manage a full-time, professional career as a professor.
Her mother expressed concerns about her career path as a researcher, intimately
aware of the time and dedication required for the job as Dr. Kunkel’s father
was a professor of physics at the University of California, Berkeley. Although
her parents did encourage her curiosity and to pursue the opportunity, her
mother did not believe that Dr. Kunkel, who was in a serious relationship at
the time, would be able to “be a mom with kids and a homelife and be a
professor.” Along with these concerns, Dr. Kunkel found there was a lack of
role models who could show her that this was in fact possible. She stated, “I
wanted to look around and try to find role models or examples of what I wanted
to do…[but] there weren’t a lot of role models for me at the time.” From her
perspective as a professor, Dr. Kunkel emphasized the importance of role
models. She said,
There has to be that first role model…. I think if you’re going to
be the only woman, and if everybody is white, the only woman of color, that’s
two barriers. You have to be the first one, and you have to be the role model?
That’s a lot to do…. I teach a freshman biology class in which we have a lot of
attrition in that first semester because it’s a challenging class. A lot of
people go, ‘Oh my gosh, I can’t handle this.’ And, what we think would be
helpful would be…that all the students could see themselves as scientists
regardless of their background, [whether they’ve] taken AP Biology [or are] the
first generation to go to college [or if] they’re black. How can we help them
see themselves as succeeding there?
Another difficulty with being a woman
in science was that she found it hard to be recognized for her accomplishments.
When she was receiving more opportunities than some of her male colleagues, she
said, “Some of them [said], ‘You’re getting all of these interviews because
you’re a woman.’ Like ouch, I’m a good scientist and I’m a woman.” She also
recalled a story from her years as a postdoc:
I think I did experience some of that when I was a postdoc, and I
remember at some point [my co-postdoc] was trying to tell the boss about my
results. And finally I just said, ‘Let me tell him. I did this.’ I don’t know
if he was consciously trying to grab the credit for it, if he was thinking I
couldn’t speak for myself, or what was he doing. The funny thing is this guy is
a very very good friend of mine to this day. We had a few rough times in there
where I had to just say, ‘Back off guy!’
Despite these past experiences, Dr. Kunkel believes that things
are changing for the better. She believes that while the situation is still not
perfect, there has been an increase in the number of role models that women can
look to to know that they can actively pursue science. With additional focus on
the effect of implicit bias and more strategic dispersal of funding for small
labs and minorities to pursue research, Dr. Kunkel believes that we can
continue to work toward a more diverse and inclusive scientific community.
When she is not busy in her lab, Dr. Kunkel loves to be outdoors.
She enjoys hiking and gardening, which she says could be why she likes plants
so much. She is also an avid reader and is currently part of a book club where
she is exposed to many different genres and authors. When asked about her
favorite types of books she exclaimed, “I like books with strong women!”
Kamal Kumar Malukani
Dr. Jan Leach (Colorado
State University) was the recipient of the 2020 Award of Distinction from
The American Phytopathological Society. This award, the highest honor APS can bestow,
is presented on rare occasions to persons who have made truly exceptional contributions
to plant pathology. Dr. Kamal
Kumar Malukani, a postdoc in the lab of Dr. Ramesh
V. Sonti at the CSIR-Centre for Cellular and Molecular Biology in Hyderabad,
India, recently interviewed Dr. Leach to learn more about the qualities that one
needs to become a leader in the field of plant pathology.
1. Many scientists, especially those
early in their careers, find it difficult to manage a balance between their professional
and personal life. How do you manage it?
I don’t know that I did manage it particularly
well! My husband, also a plant pathologist, and I started our faculty positions
at the same time, so we were both going through the tenure and promotion process
together. We shared an understanding of the pressures and demands of our positions.
We respected and, very importantly, supported each other’s choices and challenges,
which really helped as we worked through the ranks. We joked that we often passed
each other in the door, one coming and one going, much of the early parts of our
careers. So, I would say understanding and respecting each other’s situation played
a big role.
2. Thinking back to the beginning of
your career, can you provide one or two things you wished you had known that might
have made starting your career easier?
As passionate scientists, we focus
our early training on getting deeper into the science. We are frequently very focused
on learning what is needed to support our research. But, unfortunately, we are often
not well-trained in how to manage people, which is a critical part of running a
successful lab. For me, it was “on-the-job” learning, and as a young faculty member
trying to build my program, it was a hard go. Fortunately, I found good mentors
to reach out to for sound advice. I still do that; more than 30 years of experience,
and I still reach out to mentors, some decades younger than me, for guidance on
how to handle tough people problems.
3. What do you believe is the biggest
question in the field of MPMI today, and why?
One of our biggest questions is how
we will identify and stabilize plant disease resistance in the face of a changing
climate. Adapting crops to withstand disease in the face of changing temperatures
and unpredictable weather patterns is not trivial. We have observed that some disease-resistance
genes lose efficacy with a few degrees of increase in temperatures. Other resistance
genes are more effective at high temperatures but may fail under drought conditions.
Successful crop production in the future will likely depend on more complex solutions,
discovered by studying the plant, pathogen, and environment as an interacting system
(phytobiome) and integrating more diverse options into our tool kits. Successful
translation of those solutions will likely require those of us in MPMI to work even
more closely with those nearer to the field and the growers, including breeders,
agronomists, and extension specialists.
4. You have been involved in a lot
of science, as well as the administrative side of work. How do you manage this transformation?
The secret is working with talented,
independent, and smart people who are patient with my split position. I have kept
my research program running because it is the candy in my job, i.e., the part of
the job where I am most comfortable and find the most joy. It also helps keep me
grounded in the issues and challenges faced by the faculty I serve as associate
dean for research. Balancing the two parts of the job is difficult, and I battle
the constant feeling that I am not doing either job very well. But, we all have
a limited time, and I try to give the best output in both parts with the help of
people around me.
5. What advice would you like to give
to emerging scientist that will help them in the long run?
Probably the best advice I received
as an assistant professor was “Choose your battles wisely!” In other words, consider
carefully if this is a cause or battle that is really important and worth investing
your time and energy. You only have so much energy and time…conserve them for the
important causes and issues.
I had the pleasure of interviewing
Pamela Ronald who was recently awarded the 2020 World Agriculture
Prize for her achievements in agricultural research and science education.
Dr. Ronald is a leader in the research field of plant responses to
environmental and pathogen stresses. Additionally, she is an advocate and
educator for sustainable food practices and modern crop breeding strategies.
She has a fabulous TED
talk and has written a book with her husband on modern crop science
and organic farming practices titled Tomorrow’s
Table: Organic Farming, Genetics and the Future of Food.
This Q&A session was designed to learn more about
her accomplishments, understand the challenges humanity faces in food
production, and the ways science has and continues to address these issues.
1. In your own words, can you provide a brief introduction of your
research and interests?
“I have been working on the interaction
between plants and microbes for many years. My interest in this research
started when I was an undergraduate. My plant physiology professor at Reed
College taught me about plant–microbe interactions, and it sparked my interest.
Then, while doing my masters at Stanford, Dr. Brian Staskawicz
came and gave a talk on his lab’s work, and it left an impression on me. After
my Ph.D. work, I decided to work in Dr. Staskawicz’s lab. There I focused on
plant–microbe interactions, where I have now spent a bulk of my career.”
At the helm of her own lab, Dr. Ronald and her
a receptor in rice, using positional cloning. This receptor confers resistance
to the devastating Xanthomonas oryzae pv.
oryzae pathogen. Almost immediately after
publication, “a colleague of mine that I had known for several years, Dr. Dave Mackill,
came by my office and asked if I would help him isolate another gene in rice
that plays a role in stress tolerance. I was immediately interested.” This
turned out to be instrumental for conferring tolerance to submergence. Its
discovery led to an, “exciting international project to create flood-tolerant
rice varieties for farmers in India and Bangladesh.”
2. Can you go a bit more in-depth about the creation and
distribution of Sub1A
“Well this whole process was
started by the International Rice Research Institute (IRRI). The mission of IRRI is to help abolish poverty and hunger in regions that depend on
rice for most of their calories.
Rice fields in India and
Bangladesh were constantly being flooded, resulting in devastating yield
losses, so farmers looked to the scientists at IRRI to help. At the time, IRRI
had built up a large and diverse rice seed collection, which they used to
screen rice varieties for submergence tolerance.
Dave Mackill had worked in South
Asia before working at UC Davis and knew how important this work was.
Researchers at IRRI had identified a rice variety with tolerance to
submergence. Dave then mapped the submergence tolerance (Sub1) trait as a
quantitative trait locus (QTL). This was when Dave came to me and asked if we
could collaborate on isolation of Sub1 using positional cloning. We were
successful and named the key gene Sub1A.
Dave used marker-assisted breeding
to introgress Sub1A
into commonly used rice varieties. This breeding practice is not considered a
genetically modified organism (GMO) and is not regulated. IRRI researchers
collaborated with breeders at breeding stations in India and Bangladesh to test
the performance of the Sub1
varieties.” Last year, 6 million farmers in India and Bangladesh grew Sub1 rice with an
average yield advantage of 60% after flooding.” See
this perspective for more information.
3. If you were to make the argument for GMO products to someone
against it, what would you tell them?
“Well, I would first try to understand
what they were afraid of. The term GMO means something different to everyone.
Interestingly, GMO isn’t even used by the FDA because genetically modified
organism doesn’t accurately describe any breeding process really. Often, a
person who identifies as ‘anti-GMO’ is afraid of large corporations like
Monsanto, or they heard that ‘GMOs’ require more chemicals, and they don’t like
that. This is why it’s really important to understand the root of each person’s
fears of GMOs, so you can narrow the discussion to address individual
When trying to explain to a group
of people why modern genetics is useful in agriculture, I think it’s important
to give specific examples. That’s the one thing that just changes people’s
mind. Two examples I usually give are genetically
engineered papaya that are resistant to the deadly Papaya ringspot virus and Bt
eggplant in Bangladesh that reduces the need to spray
chemical insecticides. Both genetically engineered crop varieties have improved
plant yields and the lives farmers.
Now in the world of COVID-19, more
people are familiar with viruses and their infective nature. This is a good
example, because some people may be interested to know that viruses also infect
plants. This allows you to then engage people by using their knowledge about
the vaccine for COVID-19 to explain the techniques used by plant scientists to
ward off pathogens. Also, something I realized while writing my book was, why
would the average American know a lot about farming? And, how much would they
actually know about it? This is also a really important thing to keep in mind
when talking about GMOs with people. Many people may not understand or know the
farming practices used today and what challenges farmers face.”
4. In your point of view, what are some of the toughest challenges
facing agriculture right now? And, how might agriculture look in 2040 to
address these problems?
“I think problems associated with
climate change, like increased flooding, which I’m now more aware of, droughts,
and unpredictable insect infestations, like the
fall armyworm sweeping through Africa, are going to be tough. There are
scientists and modelers trying to predict new infestation events, but it is
proving very difficult. The work we do now is similar to what breeders have
been doing for 100 years or so, but we now have to work smarter and faster to
keep up with all of the changes occurring around the world.
Additionally, we will have to
start growing more food, while reducing emissions. This is something that
wasn’t really being talked about when I first entered the field. It was more
about reducing chemical inputs. So, now we have to also think about enhancing
soil fertility, reducing greenhouse gas emissions, and using water more
This is seemingly a daunting task;
however, Dr. Ronald is optimistic that scientists can work toward solutions.
“The field is rapidly advancing, and new technologies are now starting to be
developed and tested to address these problems.”
5. In your mind, what are some of the most intriguing questions
concerning pattern recognition receptors and their role in plant immunity?
“Well, I think an emerging topic
that is still sort of a black box is the relationship between development and
immunity. There is great work from Dr. Joanne Chory
and others on the SERK receptors that are involved in both immunity and
development. When this relationship was discovered years ago it was pretty
surprising, and now there are many great examples of the relationship between
development and immunity.
I think the other complicated
aspect of this area is that immunity has been traditionally thought of as a
linear concept—immunogen interacts with receptor, and this induces a linear
pathway that results in a response. However, we now know that the responses to immunogens
are much more complex than this. For instance, there are receptor complexes and
receptors that can double dip into immunity and development. I think trying to
sort out the balance and inner workings of this is really fascinating and will
be studied for a long time.”
6. For pattern recognition receptors (PRRs) and resistance (R)
genes, what needs to be done to increase their use and efficacy against
“There are examples where
different resistance genes have been stacked [placing multiple R genes into a
plant], and this provided additive and, hopefully, more durable resistance. I
think some steps to improve the process will be trying to predict how resistant
and durable these added genes will be in a crop plant. This involves doing
epidemiological studies where you think about the population diversity of the
pathogen in the field. This allows you to predict the types of mechanisms the
pathogen has to overcome and the methods being placed into plants to confer
durable resistance. You really need to know the effector repertoire of a
pathogen population and the interactions they have with the receptors of
interest. This allows you to answer the question, ‘Are there pathogen strains
in the field that can already overcome the R gene(s) or PRR(s) being added?’
There really is no shortcut to the process of engineering durable resistance.
We are still learning a lot about
utilizing plant immune components to increase pathogen resistance. For example,
being able to introduce many R genes at a single time in a cassette of genes
would be a great step forward. Currently, it takes a long time to breed many R
genes into a population. If people become more accepting of genetic
engineering, this could decrease the time needed to introduce resistance genes
into plants, which is exciting.
For a long time, there has been the hypothesis
that PRRs that recognize conserved virulence factors or immunogens would be
more durable in the field than R genes. However, I don’t think this has been
very well validated or tested in the field. One reason may be because much of
the research on PRRs, like FLS2, is carried out on non-crops. So there are very
few studies that examine if these theories hold up in the field. Even for Xa21, where plants
carrying this gene have been grown in the field for years now, there really
hasn’t been any thorough epidemiological studies to determine if this
resistance is indeed more durable than the resistance provided by other types
of resistance genes such as NBS-LRR genes. Researchers have discovered
bacterial strains that evade Xa21 in the field; however, to my knowledge it is not known
if they become problematic to farmers. So, what does that mean? Does the
evolution of the ability to evade Xa21-mediated immunity result in strains that are
compromised in virulence somehow? You really can’t determine this unless you do
large-scale field trials that look at the pathogen population over time.”
The December 2020 Editor’s Pick
for MPMI is “Sec-Delivered
Effector 1 (SDE1) of ‘Candidatus
Liberibacter asiaticus’ Promotes Citrus Huanglongbing,”
in which Kelley Clark
and co-authors demonstrate the effect that the SDE1 protein from the citrus greening
(huanglongbing) pathogen can have on plants. Their results show that the effector
is an important virulence factor that induces premature senescence-like responses
in both Arabidopsis and citrus host plants.
Sec-Delivered Effector 1 (SDE1)
Liberibacter asiaticus’ Promotes Citrus Huanglongbing
Name: Kelley J. Clark
Postdoctoral researcher, University of Arkansas (located at USDA-ARS Salinas, CA).
Ph.D. degree in microbiology and plant pathology at the University of California,
Riverside, and B.S. degree in plant sciences at the University of Arizona.
Gardening, traveling to national parks, hiking, walking my cat.
Bio: Currently, I am a postdoctoral researcher for the University
of Arkansas, but stationed in Salinas, CA, at the USDA-ARS facilities. My research
project is on spinach downy mildew, and I am located in the Salinas Valley because
it is the “salad bowl of the world,” producing the majority of the leafy greens
we consume! The research recently published in MPMI is the final chapter of my Ph.D. thesis from
my time at UC Riverside under the supervision of Prof. Wenbo Ma. Our overarching goal was
to understand how an effector of Candidatus Liberibacter asiaticus contributes to huanglongbing
(HLB) disease progression. More specifically, for this publication we wanted to
understand how the effector SDE1 contributes to leaf yellowing in Arabidopsis and
how this relates to HLB yellowing symptoms in citrus.
project challenged me on many levels, both intellectually and emotionally, especially
as my passion for research progressed and I grew as a scientist. The HLB-associated
pathogen, Ca. L.
asiaticus, is obligate, which presents many obstacles, but also opportunities, for
novel research. During my Ph.D. studies, I was fortunate to learn several new techniques,
have access to state-of-the art technology, and collaborate with distinguished scientists.
For this project, we had access to SDE1-transgenic citrus, which would not have
been possible without help from our collaborators Prof. Nian Wang and Dr. Zhiqian Pang at the
University of Florida. Additionally, we implemented NanoString technology to directly
measure the transcript quantity of specific genes in citrus. Although this technology
is widely used in medical research, it holds tremendous potential for plant–microbe
interaction research, as well as other fields of study.
addition to gaining a technical skill set, I grew passionate about citriculture
from studying its history in Riverside, CA. When I moved to Riverside to pursue
my Ph.D. research, I volunteered at the California Citrus State Historic Park. The
park consists of more than 250 acres of citrus groves showcasing more than 80 different
citrus varieties and includes a museum highlighting the history of citrus in California.
Did you know that Riverside is home to the parent Navel orange tree planted by Eliza Tibbets
tree is still alive today,
and you can visit it on the corner of Magnolia and Arlington Streets, but due to
the threat of HLB, the tree is covered with a mesh tent to keep out the insect vector
that transmits Ca.
L. asiaticus. Volunteering at the park gave me the opportunity to immerse myself
in the rich culture of citrus and see others admire it is as well, which drove my
research efforts, since HLB continues to threaten not only the citrus industry,
but our connection to its past, present, and future.
look forward to working on more challenging and insightful projects in the future,
incorporating both the knowledge I gained from this research and the inspiration
I drew from learning about the agricultural history of a specific crops.
Interactions between plants and
microbes are shaped by the physical world that surrounds them. In nature, the
abiotic environment is complex, and factors such as nutrient and water
availability, humidity, wind, carbon dioxide levels, salt, pollutants, and
temperature all affect the growth and physiology of plants and microbes, as
well as their interactions.
Much of our mechanistic
understanding of plant–microbe interactions comes from experiments done under
carefully controlled conditions. How do aspects of the abiotic environment affect
these plant–microbe interactions? Conversely, how do plant–microbe interactions
affect host response to abiotic stress?
The importance and immediacy of
these questions was reflected in the selection of the interactions between
plants, microbes, and environmental conditions as question
2 of the Top 10 Unanswered Questions in MPMI.
Focus Issue Editors Jacquie Bede, Kenichi Tsuda, and Jeanne Harris are inviting
research and review articles that explore the complex interactions between
plants, microbes, and the abiotic environment. Articles highlighting
translational research, as well as fundamental understanding, are welcome. We
look forward to assembling an issue that highlights the excellent research in
The submission deadline is July 24, 2021.
Learn more about this focus issue.
The freely available What’s New in
virtual seminar series has been a great way for IS-MPMI members to stay
connected to their science and for MPMI journal authors to present their work to
a global audience. There are currently 11 seminars available for immediate
Coming up next, we are excited to
host Kenichi Tsuda,
who will discuss Top
10 Question #5: Does ETI potentiate and restore
PTI—or is there really a binary distinction between ETI and PTI? Read
his review of the topic. This free
seminar will be held March 22 at 8:00 p.m. CDT (9:00 p.m. EDT) and March 23 at
9:00 a.m. (Beijing, CST). Access this
page to register in advance to attend or check back to watch it later.
Other Upcoming Seminars
April 12, 2021, 10:00 a.m. CDT (11:00 a.m. EDT)
Barbara Kunkel presents “Dual
Role of Auxin in Regulating Plant Defense and Bacterial Virulence Gene
Expression During Pseudomonas
syringae PtoDC3000 Pathogenesis.”
May 3, 2021, 10:00 a.m. CDT (11:00 a.m. EDT)
Cara Haney and David
Thoms discuss Top 10 Question #1:
How do plants engage with beneficial microorganisms while at the same time
Register for all seminars or watch
past seminars here.
IS-MPMIConnect, the society’s exciting new virtual discussion space,
hosted two events in February. The symposium held on February 17 focused on
Mental Health and Dealing with Failure and was moderated by DeQuantarius (DJ) Speed (University of Chicago).
The panelists included Dr. Gbonjubola Abiri (CEO of Redi-Med Consulting Services, Lagos, Nigeria), Dr. Jean Greenberg (University of Chicago),
and Goodluck Benjamin (INRAE, France). Approximately
40 participants listened to presentations by the panelists on various topics
related to dealing with stress, coping with problems, learning from failure,
and coming up with unique solutions to overcome problems.
Dr. Abiri discussed dealing
with failure and our tendency to look at every situation as a competition. She
emphasized that to succeed, we need to learn from failure and see it as an
opportunity to look back and make changes. She noted that “failure is life’s
greatest teacher” and encouraged listeners to “fail forward.”
Goodluck Benjamin shared
many personal anecdotes about his journey growing up in Nigeria. His
inspirational lesson focused on accepting a certain amount of responsibility
for your situation and coming up with a plan to deal with situations in the
future to get where you want to be. “When you fail in a situation, it does not
mean you are a failure,” he said, and encouraged everyone to tell themselves
that they can deal with, and learn from, any situation.
Dr. Greenberg shared her
experiences of dealing with failure by becoming a problem solver. She
emphasized the importance of surrounding yourself with “a community that
supports not only your science, but other aspects of your life.” Her
whiteboard-based talk gave great examples of how to organize your time
effectively to include self-reflection and non–work-related activities.
The IS-MPMIConnect event held
on February 24 featured Conversations with Dr. Morgan Halane, a cofounder of #BlackBotanistsWeek. Dr. Halane shared his life’s journey—from originally studying English
literature in the United Kingdom, to being inspired by molecular plant–microbe
interactions as an undergraduate student in Missouri, and finally studying as a
postdoc in South Korea and California. He went on to discuss the connections
that he made in organizing the Black Botanists group, which became so
successful they are planning another social media initiative this year and a
symposium at the Botany Conference in 2022. The Black Botanist group will be
coordinating with other BlackInX groups (e.g., BlackInBirding, BlackInMicrobiology) in the future,
and they are looking to expand undergraduate student involvement. We encourage
you to listen to the Holden Forests & Gardens Scientist Lecture that Morgan presented in November, 2020, in which he outlined
what people who are not black can do to support black scientists.
Join IS-MPMIConnect on March 29 for the complimentary LGBTQ+ Webinar, where
scientists at various stages in their professions will share their experiences
with inequality and bias in STEM. Learn how being a part of the LGBTQ+
community has influenced a variety of careers in science from panelists Breanne Kisselstein
(she/her; Ph.D. Candidate, Cornell University), Dr. Edel Perez-Lopez (he/his; assistant
professor, Université Laval), Dr. Giles Oldroyd (professor, University of Cambridge), and Chelsea Newbold
(master’s student, Oregon State University). We hope you can attend this timely
event from IS-MPMIConnect. Register today!