Plant growth‐promoting rhizobacteria (PGPR) are diverse groups of plant‐associated microorganisms, which can reduce the severity or incidence of disease during antagonism among bacteria and soil‐borne pathogens, as well as by influencing a systemic resistance to elicit defense response in host plants. An amalgamation of various strains of PGPR has improved the efficacy by enhancing the systemic resistance opposed to various pathogens affecting the crop. Many PGPR used with seed treatment causes structural improvement of the cell wall and physiological/biochemical changes leading to the synthesis of proteins, peptides, and chemicals occupied in plant defense mechanisms. The major determinants of PGPR‐mediated induced systemic resistance (ISR) are lipopolysaccharides, lipopeptides, siderophores, pyocyanin, antibiotics 2,4‐diacetylphoroglucinol, the volatile 2,3‐butanediol, N‐alkylated benzylamine, and iron‐regulated compounds. Many PGPR inoculants have been commercialized and these inoculants consequently aid in the improvement of crop growth yield and provide effective reinforcement to the crop from disease, whereas other inoculants are used as biofertilizers for native as well as crops growing at diverse extreme habitat and exhibit multifunctional plant growth‐promoting attributes. A number of applications of PGPR formulation are needed to maintain the resistance levels in crop plants. Several microarray‐based studies have been done to identify the genes, which are associated with PGPR‐induced systemic resistance. Identification of these genes associated with ISR‐mediating disease suppression and biochemical changes in the crop plant is one of the essential steps in understanding the disease resistance mechanisms in crops. Therefore, in this review, we discuss the PGPR‐mediated innovative methods, focusing on the mode of action of compounds authorized that may be significant in the development contributing to enhance plant growth, disease resistance, and serve as an efficient bioinoculants for sustainable agriculture. The review also highlights current research progress in this field with a special emphasis on challenges, limitations, and their environmental and economic advantages.

中文翻译：

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PGPR 介导诱导植物对病原体的系统抗性和生理化学改变：当前观点

植物生长促进根际细菌 (PGPR) 是植物相关微生物的不同群体，它们可以在细菌和土传病原体的对抗过程中降低疾病的严重程度或发病率，以及通过影响宿主中引发防御反应的系统抗性。植物。多种 PGPR 菌株的合并通过增强系统抗性来对抗影响作物的各种病原体，从而提高了功效。许多用于种子处理的 PGPR 会导致细胞壁的结构改善和生理/生化变化，从而导致植物防御机制中蛋白质、肽和化学物质的合成。PGPR 介导的诱导系统抗性 (ISR) 的主要决定因素是脂多糖、脂肽、铁载体、绿脓素、抗生素 2,4-二乙酰丙三醇、挥发性 2,3-丁二醇、N-烷基化苄胺和铁调节化合物。许多 PGPR 接种剂已经商业化，因此这些接种剂有助于提高作物的生长产量并有效地加强作物免受疾病的侵害，而其他接种剂则被用作生长在不同极端栖息地的原生作物和作物的生物肥料，并展示多功能植物生长促进属性。需要大量应用 PGPR 制剂以维持作物植物的抗性水平。已经进行了几项基于微阵列的研究来鉴定与 PGPR 诱导的系统抗性相关的基因。鉴定这些与 ISR 介导的作物病害抑制和生化变化相关的基因是了解作物抗病机制的重要步骤之一。因此，在这篇综述中，我们讨论了 PGPR 介导的创新方法，重点关注可能在促进植物生长、抗病性和作为可持续农业的有效生物接种剂的开发中具有重要意义的化合物的作用模式。该评论还强调了该领域当前的研究进展，特别强调了挑战、局限性及其环境和经济优势。重点关注授权化合物的作用方式，这些化合物可能对促进植物生长、抗病性和作为可持续农业的有效生物接种剂的开发具有重要意义。该评论还强调了该领域当前的研究进展，特别强调了挑战、局限性及其环境和经济优势。重点关注授权化合物的作用方式，这些化合物可能对促进植物生长、抗病性和作为可持续农业的有效生物接种剂的开发具有重要意义。该评论还强调了该领域当前的研究进展，特别强调了挑战、局限性及其环境和经济优势。