Open AccessEnhanced rhizosphere colonization of beneficial B acillus amyloliquefaciens SQR 9 by pathogen infection
Author(s) -
Liu Yunpeng,
Zhang Nan,
Qiu Meihua,
Feng Haichao,
Vivanco Jorge M.,
Shen Qirong,
Zhang Ruifu
Publication year - 2014
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/1574-6968.12406
Subject(s) - rhizosphere , bacillus amyloliquefaciens , colonization , fumaric acid , biology , fusarium oxysporum , microorganism , biofilm , microbiology and biotechnology , lateral root , citric acid , pathogen , botany , bacteria , biochemistry , mutant , genetics , arabidopsis , gene
Abstract Root exudates play important roles in root–soil microorganism interactions and can mediate tripartite interactions of beneficial microorganisms–plant–pathogen in the rhizosphere. However, the roles of organic acid components in this process have not been well studied. In this study the colonization of a plant growth‐promoting rhizobacterium, B acillus amyloliquefaciens SQR 9, on cucumber root infected by F usarium oxysporum f. sp. cucumerinum J. H. Owen ( FOC ) was investigated. Chemotaxis and biofilm formation response of SQR 9 to root exudates and their organic acid components were analysed. Infection of FOC on cucumber had a positive effect (3.30‐fold increase) on the root colonization of SQR 9 compared with controls. Root secretion of citric acid (2.3 ± 0.2 μM) and fumaric acid (5.7 ± 0.5 μM) was enhanced in FOC ‐infected cucumber plants. B acillus amyloliquefaciens SQR 9 exhibited enhanced chemotaxis to root exudates of FOC ‐infected cucumber seedlings. Further experiments demonstrated that citric acid acts as a chemoattractant and fumaric acid as a stimulator of biofilm formation in this process. These results suggest that root exudates mediate the interaction of cucumber root and rhizosphere strain B. amyloliquefaciens SQR 9 and enhance its root colonization.