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摘要 枯草芽胞桿菌XF-1是一株大白菜内生生防菌，通过叶面喷施的方式可有效防控大白菜根肿病，但其叶际定殖的分子机制尚不明确。为了明确表面活性素对XF-1在大白菜叶际定殖的影响，进一步提高其在田间应用效果，本研究通过测定生长曲线、泳动运动、群集运动和24孔细胞培养板静置培养试验，分析表面活性素对XF-1菌株生长速率、运动能力和生物膜形成水平的影响;利用叶片-微生物互作分析和定殖试验，测定XF-1及突变体XF-1-ΔsrfA在大白菜叶表黏附和植株内的定殖能力。结果表明，XF-1-ΔsrfA与XF-1相比生长曲线没有明显差异，泳动能力和群集运动能力分别显著下降了36.8%和43.9%，静置培养24 h后生物膜形成能力显著下降53.9%，48 h后无显著差异。叶片-微生物互作试验中，突变体标记菌XF-1-ΔsrfA-gfp黏附效率较XF-1-gfp约下降80%。喷施接种3～7 d后， XF-1-ΔsrfA-gfp相较于XF-1-gfp在大白菜叶片内和根系中的定殖数量均显著下降。试验结果表明表面活性素对枯草芽胞杆菌XF-1在大白菜叶际定殖具有较为明显的促进作用，srfA基因的缺失显著抑制XF-1的叶际定殖能力。
关键词 表面活性素; 枯草芽胞杆菌; 定殖; 生长曲线; 群集运动; 生物膜
中图分类号： S 476
文献标识码： A
DOI： 10.16688/j.zwbh.2020580
Surfactin promotes the colonization of Bacillus subtilis XF-1 in the phyllosphere of Chinese cabbage
HE Pengjie1，2#， CUI Wenyan1，2#， HE Pengfei1， LI Xingyu1， WU Yixin1， SHAHZAD Munir1， HE Yueqiu1*
（1. State Key Laboratory for Conservation and Utilization of Bio-resources in Yunnan， Yunnan Agricultural
University，Kunming 650201， China; 2. Faculty of Basic Medicine， Guizhou University of
Traditional Medicine， Guiyang 550025， China）
Abstract
Bacillus subtilis XF-1 strain， an endophytic biocontrol bacterium， was isolated from Chinese cabbage rhizosphere， which could effectively control clubroot disease of Chinese cabbage through foliar-spaying， but the molecular mechanisms of its colonization in the phyllosphere of Chinese cabbage are still unclear. To determine the effect of surfactin on the colonization of XF-1 in the phyllosphere of Chinese cabbage and provide theoretical instructions for improving the agricultural application of B.subtilis XF-1， the growth curves， motility and biofilm formation of strain XF-1 and mutant XF-1-ΔsrfA were analyzed through static culture and biofilm assays on swimming and swarming agars and in 24-well plates， respectively. Then， the bacterial attachment onto plant leaf surface and colonization in plant tissues of XF-1 and its mutant XF-1-ΔsrfA were checked based on leaf-microbe interaction analysis and colonization assays. The results showed that， compared to wild type XF-1， there was no significant difference in the growth curve of XF-1-ΔsrfA; the swimming and swarming abilities of XF-1-ΔsrfA were significantly reduced by 36.8% and 43.9%， respectively， and the ability of biofilm formation of mutant XF-1-ΔsrfA was significantly reduced by 53.9% after 24 h， but there was no statistical difference after 48 h. Moreover， compared with XF-1-gfp， adhesion efficacy of
关键词 表面活性素; 枯草芽胞杆菌; 定殖; 生长曲线; 群集运动; 生物膜
中图分类号： S 476
文献标识码： A
DOI： 10.16688/j.zwbh.2020580
Surfactin promotes the colonization of Bacillus subtilis XF-1 in the phyllosphere of Chinese cabbage
HE Pengjie1，2#， CUI Wenyan1，2#， HE Pengfei1， LI Xingyu1， WU Yixin1， SHAHZAD Munir1， HE Yueqiu1*
（1. State Key Laboratory for Conservation and Utilization of Bio-resources in Yunnan， Yunnan Agricultural
University，Kunming 650201， China; 2. Faculty of Basic Medicine， Guizhou University of
Traditional Medicine， Guiyang 550025， China）
Abstract
Bacillus subtilis XF-1 strain， an endophytic biocontrol bacterium， was isolated from Chinese cabbage rhizosphere， which could effectively control clubroot disease of Chinese cabbage through foliar-spaying， but the molecular mechanisms of its colonization in the phyllosphere of Chinese cabbage are still unclear. To determine the effect of surfactin on the colonization of XF-1 in the phyllosphere of Chinese cabbage and provide theoretical instructions for improving the agricultural application of B.subtilis XF-1， the growth curves， motility and biofilm formation of strain XF-1 and mutant XF-1-ΔsrfA were analyzed through static culture and biofilm assays on swimming and swarming agars and in 24-well plates， respectively. Then， the bacterial attachment onto plant leaf surface and colonization in plant tissues of XF-1 and its mutant XF-1-ΔsrfA were checked based on leaf-microbe interaction analysis and colonization assays. The results showed that， compared to wild type XF-1， there was no significant difference in the growth curve of XF-1-ΔsrfA; the swimming and swarming abilities of XF-1-ΔsrfA were significantly reduced by 36.8% and 43.9%， respectively， and the ability of biofilm formation of mutant XF-1-ΔsrfA was significantly reduced by 53.9% after 24 h， but there was no statistical difference after 48 h. Moreover， compared with XF-1-gfp， adhesion efficacy of