Mishu Nusrat Jahan, Hasan Md Robiul, Islam Shah Mohammad Naimul, Nayeema Jannatun, Hossain Md Motaher
Department of Plant Pathology, Gazipur Agricultural University, Gazipur, Bangladesh.
Institute of Biotechnology and Genetic Engineering (IBGE), Gazipur Agricultural University, Gazipur, Bangladesh.
PLoS One. 2025 Jul 30;20(7):e0329368. doi: 10.1371/journal.pone.0329368. eCollection 2025.
Southern blight, caused by Sclerotium rolfsii, poses a significant economic threat to tomato cultivation. This study involved the isolation, characterization, and evaluation of three selected Trichoderma isolates (Tri2, Tri3, and Tri6), applied individually and in combination, for their potential to promote plant growth and suppress southern blight under both in vitro and in vivo conditions. These isolates exhibited multiple plant growth-promoting traits, including cellulase, protease, amylase, lipase, catalase, and phosphate-solubilizing activities. Furthermore, they performed as efficient antagonists, inhibiting the mycelial growth by up to 88.8% and the oxalic acid production of S. rolfsii by up to 81.9%. The Trichoderma isolates significantly enhanced tomato seed germination and seedling vigor (p < 0.05). In seed tray and pot, experiments, consortium treatments (dual and triple application) demonstrated significantly greater plant height (≤168.8%), biomass (≤507.3%), leaf number (≤150%), leaf diameter (≤86.2%), chlorophyll content (≤322%), stem diameter (≤129.1%), gas exchange parameters, and root colonization than control and single treatments (p < 0.05). Additionally, these consortium treatments exhibited significantly higher efficacy in reducing damping-off (≤92%) and southern blight severity (≤80%) caused by S. rolfsii, compared to untreated plants (p < 0.05). Biochemical analyses revealed that Trichoderma-treated plants challenged with S. rolfsii showed reduced oxidative stress, evidenced by lower hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) levels. The treatments also increased osmoprotectant levels such as soluble sugars, proline, phenolics, and flavonoids, along with the activities of defense-related enzymes, including peroxidase (PO), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL), compared to S. rolfsii-infected controls (p < 0.05). Under field conditions, treating S. rolfsii-inoculated plants with Trichoderma isolates, whether singly, in pairs, or as a trio, significantly increased plant height, yield, and fruit Brix content (p < 0.05). The consortium application (Tri2 + Tri3 and Tri2 + Tri3 + Tri6) led to the highest increases in plant height (≤94%), fruit number (≤114%), yield (≤19.59 t/ha), and Brix (≤4.88). These findings suggest that the additive interactions among Trichoderma isolates enhance tomato growth and suppress S. rolfsii, offering an eco-friendly and effective strategy for managing southern blight.
由齐整小核菌引起的白绢病对番茄种植构成了重大经济威胁。本研究涉及对三种选定的木霉菌株（Tri2、Tri3和Tri6）进行分离、特性鉴定和评估，单独或组合应用这些菌株，以研究它们在体外和体内条件下促进植物生长和抑制白绢病的潜力。这些菌株表现出多种促进植物生长的特性，包括纤维素酶、蛋白酶、淀粉酶、脂肪酶、过氧化氢酶和溶磷活性。此外，它们还是高效的拮抗剂，可抑制齐整小核菌的菌丝生长达88.8%，并抑制其草酸产生达81.9%。木霉菌株显著提高了番茄种子的发芽率和幼苗活力（p < 0.05）。在育苗盘和花盆试验中，组合处理（双重和三重应用）显示，与对照和单一处理相比，株高（≤168.8%）、生物量（≤507.3%）、叶片数量（≤150%）、叶片直径（≤86.2%）、叶绿素含量（≤322%）、茎直径（≤129.1%）、气体交换参数和根部定殖均显著更高（p < 0.05）。此外，与未处理的植株相比，这些组合处理在降低由齐整小核菌引起的猝倒病（≤92%）和白绢病严重程度（≤80%）方面表现出显著更高的效果（p < 0.05）。生化分析表明，用木霉菌处理并受到齐整小核菌挑战的植株显示出氧化应激降低，这表现为过氧化氢（H₂O₂）和丙二醛（MDA）水平较低。与受齐整小核菌感染的对照相比，这些处理还提高了渗透保护剂的水平，如可溶性糖、脯氨酸、酚类和黄酮类，以及防御相关酶的活性，包括过氧化物酶（PO）、多酚氧化酶（PPO）和苯丙氨酸解氨酶（PAL）（p < 0.05）。在田间条件下，用木霉菌株单独、成对或作为三联体处理接种了齐整小核菌的植株，显著提高了株高、产量和果实糖度（p < 0.05）。组合应用（Tri2 + Tri3和Tri2 + Tri3 + Tri6）导致株高（≤94%）、果实数量（≤114%）、产量（≤19.59吨/公顷）和糖度（≤4.88）的增加幅度最大。这些发现表明，木霉菌株之间的加性相互作用增强了番茄的生长并抑制了齐整小核菌，为管理白绢病提供了一种生态友好且有效的策略。
