Biocontrol activity of Bacillus velezensis against Ralstonia solanacearum race 1 biovar 3 in tomato: insights from defence induction, and functional analysis

IF 3.6 3区农林科学 Q2 PLANT SCIENCES

Physiological and Molecular Plant Pathology Pub Date : 2026-05-01 Epub Date: 2026-02-11 DOI:10.1016/j.pmpp.2026.103138

Sheneka Rajendran , Ricardo Oliva , Shajith Basha Jaffer , Thiribhuvanamala Gurudevan , Karthikeyan Subburamu , Kumar K. Krishnasamy , Ramasamy Srinivasan , Shanthi Mookiah , Angappan Kathithachalam , Karthikeyan Muthusamy

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引用次数: 0

Abstract

Bacterial wilt, caused by Ralstonia solanacearum, is one of the most destructive diseases of tomato, with biovar 3 race 1 isolates predominant in India. The present study investigated rhizosphere bacterial isolates (ToRB-1 to ToRB-45) for their antagonistic potential against a virulent R. solanacearum isolate Rs-TN-02. Among these, the cell-free supernatants of isolates ToRB-7, ToRB-23, and ToRB-26 exhibited greater inhibition in agar diffusion assays. Molecular characterization using 16S rRNA and DNA gyrase genes identified these isolates as Bacillus velezensis. Chemical profiling using gas chromatography–mass spectrometry revealed the presence of several secondary metabolites, and selected compounds were subjected to in silico docking analysis with virulence-related proteins of R. solanacearum. Scanning electron microscopy of co-cultured broth indicated the predominance of B. velezensis cells and observable morphological alterations in Rs-TN-02. Under in vitro conditions, the isolates demonstrated multiple plant growth-promoting traits, including IAA, ammonia, HCN, and siderophore production, as well as phosphorus and zinc solubilization. In a glasshouse experiment, their combined application enhanced seed germination (97.33%), shoot length (37.9 cm) and root length (15.6 cm), and reduced bacterial wilt incidence by 88.13% compared with the untreated control. Treated plants showed enhanced defence enzyme activities and total phenol content. RT-qPCR analysis of selected defence-related genes indicated a positive transcriptional response with a 3.6-fold increase in NPR-1 expression. Overall, the study highlights the antagonistic, plant growth-promoting, and disease-suppressive attributes of B. velezensis isolates under controlled experimental conditions, supporting their potential inclusion in integrated and sustainable management strategies for tomato bacterial wilt, pending further field-level validation.

查看原文本刊更多论文

velezensis芽孢杆菌对番茄番茄枯萎病1种生物变种3的生物防治活性：来自防御诱导和功能分析的见解

番茄青枯病是番茄最具破坏性的病害之一，在印度以生物品种3小种1分离株为主。本研究研究了根际细菌分离株（ToRB-1 ~ ToRB-45）对毒力极强的茄青霉分离株Rs-TN-02的拮抗潜力。其中，分离物ToRB-7、ToRB-23和ToRB-26的无细胞上清液在琼脂扩散试验中表现出更大的抑制作用。利用16S rRNA和DNA旋切酶基因进行分子鉴定，鉴定这些分离株为芽孢杆菌。利用气相色谱-质谱分析发现了几种次生代谢物的存在，并将选定的化合物与番茄红霉毒力相关蛋白进行了硅对接分析。共培养肉汤的扫描电镜结果显示，白螺旋体细胞占优势，Rs-TN-02细胞形态发生明显变化。在体外条件下，分离物表现出多种植物生长促进性状，包括IAA、氨、HCN和铁载体的生产，以及磷和锌的溶解。在温室试验中，与未处理对照相比，两种药剂联合施用可提高种子发芽率（97.33%），提高茎长（37.9 cm）和根长（15.6 cm），降低青枯病发生率（88.13%）。处理后的植株防御酶活性和总酚含量均有所提高。对选择的防御相关基因进行RT-qPCR分析显示，转录反应呈阳性，NPR-1表达增加3.6倍。总的来说，该研究强调了在受控的实验条件下，velezensis分离物的拮抗、促进植物生长和抑制疾病的特性，支持了它们在番茄青枯病的综合和可持续管理策略中的潜力，有待于进一步的田间验证。

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来源期刊

Physiological and Molecular Plant Pathology 生物-植物科学

CiteScore

4.30

自引率

7.40%

发文量

130

审稿时长

38 days

期刊介绍： Physiological and Molecular Plant Pathology provides an International forum for original research papers, reviews, and commentaries on all aspects of the molecular biology, biochemistry, physiology, histology and cytology, genetics and evolution of plant-microbe interactions. Papers on all kinds of infective pathogen, including viruses, prokaryotes, fungi, and nematodes, as well as mutualistic organisms such as Rhizobium and mycorrhyzal fungi, are acceptable as long as they have a bearing on the interaction between pathogen and plant.