Belt Katharina, Foley Rhonda C, O'Sullivan Cathryn A, Roper Margaret M, Singh Karam B, Thatcher Louise F
Commonwealth Scientific and Industrial Research Organisation (CSIRO) Agriculture and Food, Floreat, WA, Australia.
Commonwealth Scientific and Industrial Research Organisation (CSIRO) Agriculture and Food, St Lucia, QLD, Australia.
Front Mol Biosci. 2021 Sep 3;8:708530. doi: 10.3389/fmolb.2021.708530. eCollection 2021.
are soil-borne Actinobacteria known to produce a wide range of enzymes, phytohormones, and metabolites including antifungal compounds, making these microbes fitting for use as biocontrol agents in agriculture. In this study, a plant reporter gene construct comprising the biotic stress-responsive glutathione S-transferase promoter GSTF7 linked to a luciferase output (GSTF7:luc) was used to screen a collection of Actinobacteria candidates for manipulation of plant biotic stress responses and their potential as biocontrol agents. We identified a isolate (KB001) as a strong candidate and demonstrated successful protection against two necrotrophic fungal pathogens, and , but not against a bacterial pathogen (). Treatment of Arabidopsis plants with either KB001 microbial culture or its secreted compounds induced a range of stress and defense response-related genes like pathogenesis-related (PR) and hormone signaling pathways. Global transcriptomic analysis showed that both treatments shared highly induced expression of reactive oxygen species and auxin signaling pathways at 6 and 24 h posttreatment, while some other responses were treatment specific. This study demonstrates that GSTF7 is a suitable marker for the rapid and preliminary screening of beneficial bacteria and selection of candidates with potential for application as biocontrols in agriculture, including the KB001 that was characterized here, and could provide protection against necrotrophic fungal pathogens.
土壤中的放线菌已知能产生多种酶、植物激素和代谢物，包括抗真菌化合物，这使得这些微生物适合用作农业生物防治剂。在本研究中，一个植物报告基因构建体，其包含与荧光素酶输出连接的生物胁迫响应性谷胱甘肽S-转移酶启动子GSTF7（GSTF7:luc），被用于筛选一系列放线菌候选物，以操纵植物的生物胁迫反应及其作为生物防治剂的潜力。我们鉴定出一个分离株（KB001）作为有力候选物，并证明其能成功抵御两种坏死性真菌病原体，即 和 ，但不能抵御一种细菌病原体（ ）。用KB001微生物培养物或其分泌的化合物处理拟南芥植株，会诱导一系列与胁迫和防御反应相关的基因，如病程相关（PR）和激素信号通路。全局转录组分析表明，两种处理在处理后6小时和24小时均高度诱导活性氧和生长素信号通路的表达，而其他一些反应则具有处理特异性。本研究表明，GSTF7是快速初步筛选有益细菌以及选择有潜力作为农业生物防治剂应用的候选物的合适标记，包括此处表征的KB001，其可以抵御坏死性真菌病原体。
