Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India.
ICAR-Indian Agricultural Research Institute, New Delhi, India.
Plant Sci. 2021 Oct;311:111009. doi: 10.1016/j.plantsci.2021.111009. Epub 2021 Jul 27.
Weeds, pests, and pathogens are among the pre-harvest constraints in rice farming across rice-growing countries. For weed management, manual weeding and herbicides are widely practiced. Among the herbicides, glyphosate [N-(phosphonomethyl) glycine] is a broad-spectrum systemic chemical extensively used in agriculture. Being a competitive structural analog to phosphoenolpyruvate, it selectively inhibits the conserved 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) enzyme required for the biosynthesis of aromatic amino acids and essential metabolites in eukaryotes and prokaryotes. In the present study, we investigated the antifungal and defense elicitor activity of glyphosate against Magnaporthe oryzae on transgenic-rice overexpressing a glyphosate-resistance OsEPSPS gene (T173I + P177S; TIPS OsmEPSPS) for blast disease management. The glyphosate foliar spray on OsmEPSPS transgenic rice lines showed both prophylactic and curative suppression of blast disease comparable to a blasticide, tricyclazole. The glyphosate displayed direct antifungal activity on Magnaporthe oryzae as well as enhanced the levels of antioxidant enzymes and photosynthetic pigments in rice. However, the genes associated with phytohormones-mediated defense (OsPAD4, OsNPR1.3, and OsFMO) and innate immunity pathway (OsCEBiP and OsCERK1) were found repressed upon glyphosate spray. Altogether, the current study is the first report highlighting the overexpression of a crop-specific TIPS mutation in conjugation with glyphosate application showing potential for blast disease management in rice cultivation.
杂草、害虫和病原体是水稻种植国家在收获前面临的主要限制因素。在杂草管理方面，人们广泛采用人工除草和使用除草剂。在这些除草剂中，草甘膦（N-（膦酸甲基）甘氨酸）是一种广泛应用于农业的广谱性、内吸传导型化学除草剂。作为磷酸烯醇丙酮酸的竞争性结构类似物，它选择性地抑制真核生物和原核生物中芳香族氨基酸和必需代谢物生物合成所需的保守 5-烯醇丙酮酰莽草酸-3-磷酸合酶（EPSPS）酶。在本研究中，我们研究了草甘膦对转 OsEPSPS 基因（T173I + P177S；TIPS OsmEPSPS）抗稻瘟病的水稻过表达植株的抗真菌和防御诱导活性。叶面喷施草甘膦对 OsmEPSPS 转基因水稻系表现出对稻瘟病的预防和治疗抑制作用，与杀菌剂三环唑相当。草甘膦对稻瘟病菌具有直接的抗真菌活性，并提高了水稻中抗氧化酶和光合色素的水平。然而，与植物激素介导的防御（OsPAD4、OsNPR1.3 和 OsFMO）和先天免疫途径（OsCEBiP 和 OsCERK1）相关的基因在草甘膦喷施后被发现受到抑制。总之，本研究首次报道了作物特异性 TIPS 突变与草甘膦应用相结合，在水稻种植中具有稻瘟病管理的潜力。
