Effects of cotton root exudates on the rhizosphere colonization and biofilm formation of Bacillus subtilis strain NCD-2
Q. GUO (1), L. Dong (1), P. Wang (1), S. Li (1), X. Zhang (1), X. Lu (1) (1) Institute of Plant Protection, Hebei Academy of Agricultural and Forestry Sciences, China

Bacillus subtilis strain NCD-2 is an excellent biocontrol agent for biocontrolling cotton soil-borne diseases. To clarify the influence of cotton root exudates on bacterial biofilm formation and rhizosphere colonization, rhizosphere populations of strain NCD-2 were investigated on five cotton cultivars by plating-PCR counting method. Thirty-five days after seedling, the highest population of 7.63×105 CFU·g-1 root was achieved on cultivar Pima90 (G. barbadense, resistant), and followed by 4.73×105 CFU·g-1 population density on cultivar Jimian11 (G. hirsutum, sensitive), the lowest population of 6.51×104 CFU·g-1 root was achieved on cultivar Zhongzhimian2 (G. hirsutum, resistant). The GFP-tagged strain NCD-2 was created, the presence of strain NCD-2 in the rhizosphere of five cotton cultivars were detected with confocal laser scanning microscope (CLSM), results found that strain NCD-2 could keep a high population on cultivar Pima90 as well as Jimian11, but very low population on Lumian29, Zhongzhimian2, as well as Zhongmiansuo41. The root exudates were collected and the effect of root exudates on cell growth and biofilm formation of strain NCD-2 were tested. Results indicated that the root exudates of five different cotton cultivars had no effect on the growth of strain NCD-2,the root exudate from Pima90 had the strongest promoting effect on the biofilm formation, whereas the root exudate from Zhongtzhimian2 had a slight effect on the biofilm formation.

Abstract Number: P3-69
Session Type: Poster