Ahmad Muhammad, Imtiaz Muhammad, Shoib Nawaz Muhammad, Mubeen Fathia, Imran Asma
Microbial Ecology Lab, Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan.
Front Plant Sci. 2022 May 23;13:794782. doi: 10.3389/fpls.2022.794782. eCollection 2022.
Temperature is a significant parameter in agriculture since it controls seed germination and plant growth. Global warming has resulted in an irregular rise in temperature posing a serious threat to the agricultural production around the world. A slight increase in temperature acts as stress and exert an overall negative impact on different developmental stages including plant phenology, development, cellular activities, gene expression, anatomical features, the functional and structural orientation of leaves, twigs, roots, and shoots. These impacts ultimately decrease the biomass, affect reproductive process, decrease flowering and fruiting and significant yield losses. Plants have inherent mechanisms to cope with different stressors including heat which may vary depending upon the type of plant species, duration and degree of the heat stress. Plants initially adapt avoidance and then tolerance strategies to combat heat stress. The tolerance pathway involves ion transporter, osmoprotectants, antioxidants, heat shock protein which help the plants to survive under heat stress. To develop heat-tolerant plants using above-mentioned strategies requires a lot of time, expertise, and resources. On contrary, plant growth-promoting rhizobacteria (PGPRs) is a cost-effective, time-saving, and user-friendly approach to support and enhance agricultural production under a range of environmental conditions including stresses. PGPR produce and regulate various phytohormones, enzymes, and metabolites that help plant to maintain growth under heat stress. They form biofilm, decrease abscisic acid, stimulate root development, enhance heat shock proteins, deamination of ACC enzyme, and nutrient availability especially nitrogen and phosphorous. Despite extensive work done on plant heat stress tolerance in general, very few comprehensive reviews are available on the subject especially the role of microbes for plant heat tolerance. This article reviews the current studies on the retaliation, adaptation, and tolerance to heat stress at the cellular, organellar, and whole plant levels, explains different approaches, and sheds light on how microbes can help to induce heat stress tolerance in plants.
温度是农业中的一个重要参数，因为它控制着种子萌发和植物生长。全球变暖导致气温不规则上升，对世界各地的农业生产构成严重威胁。温度稍有升高就会成为一种胁迫，对包括植物物候、发育、细胞活动、基因表达、解剖特征、叶、枝、根和芽的功能及结构取向等不同发育阶段产生全面的负面影响。这些影响最终会降低生物量，影响生殖过程，减少开花和结果，并导致显著的产量损失。植物具有应对不同胁迫因素（包括高温）的内在机制，这些机制可能因植物种类、热胁迫的持续时间和程度而异。植物最初会采取避热策略，然后是耐热策略来对抗热胁迫。耐热途径涉及离子转运蛋白、渗透保护剂、抗氧化剂、热休克蛋白，这些有助于植物在热胁迫下存活。利用上述策略培育耐热植物需要大量时间、专业知识和资源。相反，植物根际促生细菌（PGPRs）是一种经济高效、节省时间且用户友好的方法，可在包括胁迫在内的一系列环境条件下支持和提高农业生产。PGPRs产生并调节各种植物激素、酶和代谢产物，帮助植物在热胁迫下维持生长。它们形成生物膜，降低脱落酸含量，刺激根系发育，增强热休克蛋白，催化ACC酶脱氨，并提高养分有效性，尤其是氮和磷。尽管总体上对植物耐热性进行了大量研究，但关于这个主题，特别是微生物对植物耐热性的作用，很少有全面的综述。本文综述了目前在细胞、细胞器和整株植物水平上对热胁迫的响应、适应和耐受的研究，解释了不同的方法，并阐明了微生物如何帮助诱导植物的热胁迫耐受性。
