Rashad Younes M, Abdalla Sara A, Sleem Mohamed M
Plant Protection and Biomolecular Diagnosis Department, Arid Lands Cultivation Research Institute, City of Scientific Research and Technological Applications (SRTA-City), New Borg El-Arab City 21934, Egypt.
Plants (Basel). 2022 Aug 5;11(15):2051. doi: 10.3390/plants11152051.
Rhizoctonia root rot is one of the most destructive diseases of tomato and other crops. The biocontrol of plant diseases using endophytic bacteria has gained significant attention due to their distinct advantages compared with the free-living ones, as well as their new unexplored and unique properties. Endophytic SR22 represents a promising and more effective biocontrol and growth-promoting agent for tomato plants than the free-living agents, being an ecofriendly and sustainable tool in modern agriculture. In this study, the direct antagonistic activity of SR22 was investigated against in vitro. The biocontrol activity of SR22 against Rhizoctonia root rot of tomato was also investigated. Effects on the level of the transcriptional expression of defense-related genes, biochemical responses, and the vegetative growth of tomato plants were also studied. The dual culture test showed 51% inhibition in the mycelial growth of due to SR22, indicating its potent antagonistic behavior. Using a GC-MS analysis, twenty bioactive compounds were detected to be produced by SR22, including chlorogenic acid, pyrrolo [1,2-a]pyrazine-1,4-dione, hexahydro, propyl thioglycolic acid, phthalic acid, and 2,3-butanediol. Under greenhouse conditions, the application of SR22 led to a reduction (up to 51%) in Rhizoctonia root rot of tomato. Furthermore, an upregulation in the expression of the responsive factor (10.9-fold) and the defense-related genes (9.1-fold) and (4.5-fold) in tomato plants was recorded due to the application of SR22. In addition, this treatment enhanced the total phenolic content (76.8%) and activity of the antioxidant enzymes POD (56%) and PPO (29.2%) in tomato roots, indicating its resistance-inducing effect on tomato plants. Moreover, this treatment enhanced most of the evaluated growth parameters in tomato plants (up to 35%). We can conclude that SR22 is a promising biocontrol agent and growth promoter in tomato plants against Rhizoctonia root rot. An evaluation of the formulation and field application of this bio-agent is necessary in future studies.
丝核菌根腐病是番茄和其他作物最具毁灭性的病害之一。利用内生细菌进行植物病害的生物防治因其与自由生活细菌相比具有明显优势，以及其尚未被探索的新的独特特性而受到广泛关注。内生菌SR22是一种比自由生活菌更有前景、更有效的番茄生物防治和促生长剂，是现代农业中一种生态友好且可持续的工具。在本研究中，对SR22对[此处原文缺失相关病菌名称]的体外直接拮抗活性进行了研究。还研究了SR22对番茄丝核菌根腐病的生物防治活性。此外，还研究了其对番茄植株防御相关基因转录表达水平、生化反应和营养生长的影响。双培养试验表明，SR22对[此处原文缺失相关病菌名称]的菌丝生长有51%的抑制作用，表明其具有强大的拮抗作用。通过气相色谱-质谱分析，检测到SR22产生了20种生物活性化合物，包括绿原酸、六氢吡咯并[1,2-a]吡嗪-1,4-二酮、丙基硫代乙醇酸、邻苯二甲酸和2,3-丁二醇。在温室条件下，施用SR22可使番茄丝核菌根腐病减少（高达51%）。此外，由于施用SR22，番茄植株中响应因子[此处原文缺失相关因子名称]（10.9倍）、防御相关基因[此处原文缺失相关基因名称]（9.1倍）和[此处原文缺失相关基因名称]（4.5倍）的表达上调。此外，该处理提高了番茄根中总酚含量（76.8%）以及抗氧化酶POD（56%）和PPO（29.2%）的活性，表明其对番茄植株具有诱导抗性的作用。此外，该处理提高了番茄植株中大多数评估的生长参数（高达35%）。我们可以得出结论，SR22是一种有前景的番茄生物防治剂和生长促进剂，可防治丝核菌根腐病。未来的研究有必要对这种生物制剂的配方和田间应用进行评估。
