辣椒溶杆菌X2-3 GntR家族中一个Hut C基因功能分析

Function Analysis of a HutC Gene of the GntR Family in Lysobacter capsici X2-3

GntR是原核生物中一类重要的转录因子。本研究分析了辣椒溶杆菌Lysobacter capsici X2-3 GntR家族中一个Hut C基因的生物学功能,结果显示LC_HutC缺失突变体MT4090的生长速率、运动能力、对小麦根系分泌物的趋向性及对小麦根系的定殖能力较野生型菌株明显减弱,生物膜产量则明显增加,互补菌株MS4090与野生型水平相当。但突变体对病原真菌和卵菌的抑菌活性没有明显变化。上述结果表明,LC_HutC对X2-3生长、运动、趋化性以及根际定殖等有广泛的调控作用,本研究结果对深入了解辣椒溶杆菌的调控机制有重要参考。

GntR is a large family of transcriptional regulators and is further divided into seven subfamily based on the sequence similarities of C-terminal effector binding. As the second-largest subfamily of GntR, HutC comprise about 30% of GntR regulators. HutC has been reported in regulating various biological processes in divers of bacteria, however little is known about its regulation in PGPR(plant growth-promoting rhizobacteria)especially in Lysobacter capsici. The goal of this study was to analyze the functional characteristic of a Hut C gene in Lysobacter capsici. As showed in this study, deletion of LC_HutC in L. capsici X2-3 reduced the bacterial growth rate, motility,chemotaxis to wheat root exudates and rhizosphere colonization of wheat, and increased the biofilm formation significantly. However, no significant changes in the antimicrobial activity of the LC_HutC mutant against either fungi or oomycetes were observed. These results suggested the possible role of LC_Hut C in regulating chemotaxis,rhizosphere colonization and cell motility in L.capsici X2-3. This work expands our understanding of Hut C in regulation of chemotaxis and colonization in PGPR of L. capsici.