Basal defense against root-knot nematodes in Arabidopsis thaliana
M. TEIXEIRA (1), I. Kaloshian (2) (1) UCR, U.S.A.; (2) Professor/UCR, U.S.A.

Nematode parasitism of plants results in $US157 billion in crop losses annually. One of such parasites is the root-knot nematode (RKN; Meloidogyne spp.), a soil-inhabiting nematode that establishes elaborate feeding sites in roots. Despite detailed investigation of RKN feeding site formation, PTI responses to RKN are not well described. Investigating PTI against RKN, we found that flg22-induced PTI in Arabidopsis thaliana Col-0 plants reduced RKN penetration. Consistently, Arabidopsis PTI mutants bak1-5, bik1 and double mutant rbohD/F displayed enhanced susceptibility to RKN. Using GUS reporter lines and gene expression analysis, we observed upregulation of the PTI marker genes, transcription factors WRKY11 and MYB51 and cytochrome P450 CYP71A12, after RKN infection. WRKY11 regulates basal defense and MYB51 and CYP71A12 are involved in glucosinolates and camalexin biosynthesis, respectively. In the bak1-5 mutant, WRKY11 and MYB51 induction was absent while CYP71A12 induction was attenuated. Interestingly, GUS elicitation was also observed in the reporter lines after treatment with nematode extracts suggesting RKN is perceived in the absence of damage. Consistently, DAMP receptor mutant dorn1 and double mutant pepr1/2 did not display altered susceptibility to RKN compared to wild-type. Our results demonstrate that plants can perceive RKN and initiate PTI similar to microbial pathogens through distinct signaling pathways, one of them relying on BAK1 activity. 

Abstract Number: P17-625
Session Type: Poster