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Surfactin是由芽胞杆菌类细菌产生的一种脂肽类物质,具有溶血活性和排油能力,并且与细菌生物膜形成和根际定殖能力相关。本研究分析了PhoR/PhoP双组份对生防枯草芽胞杆菌NCD-2菌株中surfactin的合成的影响。在低磷环境下,同NCD-2野生型菌株相比,PhoR和PhoP突变子显著降低了NCD-2菌株的溶血活性;NCD-2菌株的排油能力很强,而PhoR和PhoP突变子均丧失排油能力;NCD-2野生型菌株的生物膜形成能力分别是PhoR和PhoP突变子的2.0和2.2倍。通过FPLC色谱分析技术证明NCD-2菌株可以产生surfactin,并发现在低磷条件中,野生型菌株NCD-2所产生的surfactin分别是PhoR和PhoP突变子的2.3和6.4倍。通过RT-qPCR技术分析了surfactin合成酶基因srfAA在不同菌株中的表达情况,结果表明在低磷环境下,PhoR和PhoP突变子中srfAA基因的表达量比NCD-2野生型菌株均降低了2.1倍。构建PhoR和PhoP突变子的互补菌株,证明互补菌株均能使突变子的性状恢复到野生型水平。以上结果证明,PhoR/PhoP双组份影响surfactin的合成。
Surfactin, a lipopeptide produced by Bacillus bacteria, has hemolysis and oil drainage capabilities and is associated with bacterial biofilm formation and rhizosphere colonization. This study analyzed the effect of PhoR / PhoP bicomponents on the synthesis of surfactin in the B. subtilis NCD-2 strain. Under low phosphorus conditions, PhoR and PhoP mutants significantly reduced the hemolytic activity of NCD-2 strains compared to NCD-2 wild-type strains; NCD-2 strains had a strong oil drainage capacity while both PhoR and PhoP mutants Loses the ability of oil removal. The biofilm formation ability of NCD-2 wild type strain is 2.0 and 2.2 times that of PhoR and PhoP mutant, respectively. The results of FPLC chromatographic analysis showed that NCD-2 strain could produce surfactin and found that the wild-type strain NCD-2 produced surfactin in the low-phosphorus condition at 2.3 and 6.4 times of the PhoR and PhoP mutants, respectively. The expression of surfactin synthase gene srfAA in different strains was analyzed by RT-qPCR. The results showed that the expression of srfAA gene in PhoR and PhoP mutant was lower than that of NCD-2 wild-type strain by 2.1 Times The construction of complementary strains of PhoR and PhoP mutants demonstrated that the complementation strains could restore the mutant trait to the wild type. The above results demonstrate that PhoR / PhoP two components affect the synthesis of surfactin.