Plant Pathology Department, Faculty of Agriculture, Ain Shams University, Cairo, 11241, Egypt.
Agricultural Microbiology Department, Faculty of Agriculture, Ain Shams University, Cairo, 11241, Egypt.
Microb Ecol. 2024 Jul 15;87(1):94. doi: 10.1007/s00248-024-02400-4.
Common bean (Phaseolus vulgaris L.) is an essential food staple and source of income for small-holder farmers across Africa. However, yields are greatly threatened by fungal diseases like root rot induced by Rhizoctonia solani. This study aimed to evaluate an integrated approach utilizing vermicompost tea (VCT) and antagonistic microbes for effective and sustainable management of R. solani root rot in common beans. Fourteen fungal strains were first isolated from infected common bean plants collected across three Egyptian governorates, with R. solani being the most virulent isolate with 50% dominance. Subsequently, the antagonistic potential of vermicompost tea (VCT), Serratia sp., and Trichoderma sp. was assessed against this destructive pathogen. Combinations of 10% VCT and the biocontrol agent isolates displayed potent inhibition of R. solani growth in vitro, prompting in planta testing. Under greenhouse conditions, integrated applications of 5 or 10% VCT with Serratia marcescens, Trichoderma harzianum, or effective microorganisms (EM1) afforded up to 95% protection against pre- and post-emergence damping-off induced by R. solani in common bean cv. Giza 6. Similarly, under field conditions, combining VCT with EM1 (VCT + EM1) or Trichoderma harzianum (VCT + Trichoderma harzianum) substantially suppressed disease severity by 65.6% and 64.34%, respectively, relative to untreated plants. These treatments also elicited defense enzyme activity and distinctly improved growth parameters including 136.68% and 132.49% increases in pod weight per plant over control plants. GC-MS profiling of Trichoderma harzianum, Serratia marcescens, and vermicompost tea (VCT) extracts revealed unique compounds dominated by cyclic pregnane, fatty acid methyl esters, linoleic acid derivatives, and free fatty acids like oleic, palmitic, and stearic acids with confirmed biocontrol and plant growth-promoting activities. The results verify VCT-mediated delivery of synergistic microbial consortia as a sustainable platform for integrated management of debilitating soil-borne diseases, enhancing productivity and incomes for smallholder bean farmers through regeneration of soil health. Further large-scale validation can pave the adoption of this climate-resilient approach for securing food and nutrition security.
普通菜豆（Phaseolus vulgaris L.）是非洲小农户的重要主食和收入来源。然而，真菌病害如由立枯丝核菌引起的根腐病极大地威胁着产量。本研究旨在评估一种利用蚯蚓粪茶（VCT）和拮抗微生物的综合方法，以有效和可持续地管理普通菜豆中的立枯丝核菌根腐病。首先从三个埃及省收集的感染普通菜豆植物中分离出 14 株真菌菌株，其中立枯丝核菌是最具毒力的分离株，占 50%。随后，评估了蚯蚓粪茶（VCT）、沙雷氏菌和哈茨木霉对这种破坏性病原体的拮抗潜力。10%VCT 与生物防治剂分离株的组合在体外对立枯丝核菌的生长表现出强烈的抑制作用，从而促使在植物体内进行测试。在温室条件下，5%或 10%VCT 与粘质沙雷氏菌、哈茨木霉或有效微生物（EM1）的综合应用在普通菜豆 cv.Giza 6 中提供了高达 95%的防治立枯丝核菌引起的出苗前和出苗后猝倒的保护作用。同样，在田间条件下，VCT 与 EM1（VCT+EM1）或哈茨木霉（VCT+哈茨木霉）的组合分别将病害严重度抑制了 65.6%和 64.34%，与未处理的植物相比。这些处理还诱导了防御酶活性，并明显改善了生长参数，包括每株植物的豆荚重量增加了 136.68%和 132.49%。哈茨木霉、沙雷氏菌和蚯蚓粪茶（VCT）提取物的 GC-MS 分析显示，独特的化合物主要由环孕烷、脂肪酸甲酯、亚油酸衍生物和游离脂肪酸组成，如油酸、棕榈酸和硬脂酸，具有确认的生物防治和植物生长促进活性。结果证实，VCT 介导的协同微生物联合体的传递是一种可持续的平台，用于综合管理衰弱的土传病害，通过恢复土壤健康来提高小农户的生产力和收入。进一步的大规模验证可以为采用这种具有气候恢复力的方法来确保粮食和营养安全铺平道路。
