这项研究是为了筛选对炭疽病的抗真菌活性,炭疽病,和Colletotrichumcoccodes。在体外双重培养试验中,从辣椒土壤中分离出的细菌GP-P8对所测试的病原体有效,平均抑制率为70.7%。16SrRNA基因测序分析结果表明,该菌株的有效分离菌为赛马芽孢杆菌。还进行了GP-P8的生化表征。根据结果,蛋白酶和纤维素,铁载体生产,磷酸盐溶解,淀粉水解,GP-P8显示了吲哚-3-乙酸的产生。使用特异性引物,涉及抗生素生产的基因,如iturin,芬霉素,difficidin,杆菌素,杆菌素,surfactin,大乳素,和杆菌烯也被检测到。通过固相微萃取/气相色谱-质谱(SPME/GC-MS)鉴定和分析挥发性有机化合物,发现分离的GP-P8产生了丙酮和2,3-丁二醇。体内试验表明,GP-P8显著减少了由acutatum引起的炭疽病,促进了辣椒植物的生长。辣椒果实的逆转录聚合酶链反应分析表明,GP-P8处理的辣椒植物显示出免疫基因如CaPR1,CaPR4,CaNPR1,CaMAPK4,CaJA2和CaERF53的表达增加。这些结果强烈表明,GP-P8可能是一种有前途的抗辣椒炭疽病的生物防治剂,也可能是辣椒植物生长促进剂。
This study was carried out to screen the antifungal activity against Colletotrichum acutatum, Colletotrichum dematium, and Colletotrichum coccodes. Bacterial isolate GP-P8 from pepper soil was found to be effective against the tested pathogens with an average inhibition rate of 70.7% in in vitro dual culture assays. 16S rRNA gene sequencing analysis result showed that the effective bacterial isolate as Bacillus siamensis. Biochemical characterization of GP-P8 was also performed. According to the results, protease and cellulose, siderophore production, phosphate solubilization, starch hydrolysis, and indole-3-acetic acid production were shown by the GP-P8. Using specific primers, genes involved in the production of antibiotics, such as iturin, fengycin, difficidin, bacilysin, bacillibactin, surfactin, macrolactin, and bacillaene were also detected in B. siamensis GP-P8. Identification and analysis of volatile organic compounds through solid phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS) revealed that acetoin and 2,3-butanediol were produced by isolate GP-P8. In vivo tests showed that GP-P8 significantly reduced the anthracnose disease caused by C. acutatum, and enhanced the growth of pepper plant. Reverse transcription polymerase chain reaction analysis of pepper fruits revealed that GP-P8 treated pepper plants showed increased expression of immune genes such as CaPR1, CaPR4, CaNPR1, CaMAPK4, CaJA2, and CaERF53. These results strongly suggest that GP-P8 could be a promising biocontrol agent against pepper anthracnose disease and possibly a pepper plant growth-promoting agent.