presence of a 1-aminocyclopropane-1-carboxylate (ACC) deaminase deletion mutation alters the physiology of the endophytic plant growth-promoting bacterium Burkholderia phytofirmans PsJN

• Published in: FEMS microbiology letters 2009-07, Vol.296 (1), p.131-136
• Main Authors: Sun, Yili, Cheng, Zhenyu, Glick, Bernard R
• Format: Article
• Language: English
• Subjects: ACC deaminase; Acetic acid; Bacteria; Bacterial Proteins - metabolism; Base Sequence; Brassica napus - growth & development; Brassica napus - microbiology; Burkholderia; Burkholderia - enzymology; Burkholderia - genetics; Burkholderia - physiology; Carbon-Carbon Lyases - genetics; Cellular manufacture; Clonal deletion; Deletion mutant; Elongation; endophyte; Endophytes; Gene deletion; Gene Knockout Techniques; Genetic Complementation Test; IAA; indole acetic acid; Indoleacetic acid; Indoleacetic Acids - metabolism; Microbiology; Molecular Sequence Data; Mutation; Physiology; Plant growth; plant growth promotion; RpoS; Seedlings; Seedlings - growth & development; Sequence Deletion; siderophore; Siderophores; Siderophores - metabolism; Sigma Factor - metabolism
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.2009.01625.x

The structural gene for 1-aminocyclopropane-1-carboxylate (ACC) deaminase (acdS) from the endophytic plant growth-promoting bacterium Burkholderia phytofirmans PsJN was isolated and used to construct a mutant strain B. phytofirmans YS2 (B. phytofirmans PsJN/ΔacdS), in which an internal segment of the acdS gene was deleted. The mutant YS2 lost ACC deaminase activity as well as the ability to promote the elongation of the roots of canola seedlings. Concomitant with the creation of this deletion mutant, a number of physiological changes were observed in the bacterium, including an increase in indole acetic acid synthesis, a decrease in the production of siderophores and an increase in the cellular level of the stationary-phase σ factor, RpoS. Introduction of the wild-type acdS gene into the mutant YS2 to construct strain B. phytofirmans YS3 (B. phytofirmans YS2/pRK-AcdS) restored both ACC deaminase activity and plant growth-promotion activity in strain YS3. However, the complemented mutant still showed the above-mentioned physiological changes.