Abstract：
Bacterial wilt of tomato caused by Ralstonia solanacearum is a critical soilborne disease that drastically reduces yield. In the current study, an endophytic strain NEAU-CP5 with strong antagonistic activity against R. solanacearum was isolated from tomato seeds and characterized. The strain was identified as Bacillus velezensis based on 16S rRNA gene and whole genome sequence analysis. NEAU-CP5 can secrete amylase, protease, and cellulase, and also produce known antibacterial metabolites, including cyclo (leucylprolyl), cyclo (phenylalanyl-prolyl), cyclo (Pro-Gly), 3-benzyl-2,5-piperazinedione, pentadecanoic acid, eicosane, 2-methyoic acid, isovaleric acid, dibuty phthalate, and esters of fatty acids (HFDU), which may be responsible for its strong antibacterial activity. Fourteen gene clusters associated with antibacterial properties were also identified in the whole genome sequence of NEAU-CP5. Pot experiment demonstrated that the application of 108 CFU/mL NEAU-CP5 on tomato plants significantly reduced the incidence of tomato bacterial wilt by 68.36 ± 1.67 %. NEAU-CP5 also increased the activity of defense-related enzymes (CAT, POD, PPO, SOD, and PAL) in tomato plants. This is the first report of an effective control of bacterial wilt on tomato plants by B. velezensis and highlights the potential of NEAU-CP5 as a potential biocontrol agent for the management of tomato bacterial wilt.
摘要：
由青枯雷尔氏菌引起的番茄青枯病是一种严重的土壤传播疾病，会大大降低产量。在目前的研究中,从番茄种子中分离出具有强拮抗活性的内生菌株NEAU-CP5。基于16SrRNA基因和全基因组序列分析，将该菌株鉴定为velezensis芽孢杆菌。NEAU-CP5可以分泌淀粉酶，蛋白酶，和纤维素酶，并产生已知的抗菌代谢物，包括环（亮氨醇二），环(苯丙氨酰基-丙氨酰基)，旋风(Pro-Gly)，3-苄基-2,5-哌嗪二酮,十五烷酸,二十碳烷,2-甲基酸,异戊酸，邻苯二甲酸酯，和脂肪酸酯（HFDU），这可能是其强大抗菌活性的原因。在NEAU-CP5的全基因组序列中还鉴定出14个与抗菌特性相关的基因簇。盆栽试验表明，在番茄植株上施用108CFU/mLNEAU-CP5可显着降低番茄青枯病的发生率68.36±1.67％。NEAU-CP5还增加了防御相关酶的活性(CAT，POD,PPO,SOD,和PAL）在番茄植物中。这是关于通过B.velezensis有效控制番茄植物的青枯病的第一份报告，并强调了NEAU-CP5作为管理番茄青枯病的潜在生物防治剂的潜力。
