Aggregate formation in the mopB mutant of xanthomonas campestris pv.campestris

• Main Authors: Che-Hao Tsai, 蔡哲豪
• Other Authors: 翁淑芬
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/51206217285668144886

碩士 === 國立中興大學 === 分子生物學研究所 === 97 === The Gram-negative plant pathogen Xanthomonas camperstris pv. camperstris (Xcc) causes black rot in crucifers. The virulence of this bacterium is mainly related to its ability to produce a large mount of exopolysaccharride (EPS, also called xanthan gum) , extracellular enzymes, and other virulence factor. In addition to these substances, Avr (avirulence) protein and hrp genes encoded Type III secretary pathway are also essential for virulence. The previous study showed that the Xcc mopB mutant caused the EPS production decreasing, and lost the pathogenesis of this bacterium to plants. In addition, while the wild type grew in a dispersed planktonic fashion, aggregate were in the mopB mutant. This phenotype is similar to that in the rpfF mutant. Addition of DSF triggered dispersion of the aggregates present in rpfF mutant but adding DSF to the mopB mutant dispersal has no effect. It is suggested that the structure and mechanism of aggregate are different in between mopB and rpfF mutant. However, addition of supernatant of Serratia marcescens (Sm) caused dispersal of the aggregates of mopB mutant. The SmT43 protease were purified and added to mopB mutant, the result showed the aggregates were dispersed. Moreover, base on the analysis of SDS-PAGE, the Xc17 (wild-type) and mopB mutant intracellular protein profiles were compared. One of the overexpressed profiles were identified as AtpF. AtpF Antibody were generated to find out the expression of AtpF in Xc17 and mopB mutant. when the mopB mutant form the aggregates. On the other hand, the extracellular proteins of Xc17 and mopB mutant were isolated and analyzed by 2D electrophoresis to find the possible factors related to the aggregates.