Advances in Wheat Physiology in Response to Drought and the Role of Plant Growth Promoting Rhizobacteria to Trigger Drought Tolerance

Abstract

In the coming century, climate change and the increasing human population are likely leading agriculture to face multiple challenges. Agricultural production has to increase while preserving natural resources and protecting the environment. Drought is one of the major abiotic problems, which limits the growth and productivity of crops and impacts 1–3% of all land.To cope with unfavorable water-deficit conditions, plants use through sophisticated and complex mechanisms that help to perceive the stress signal and enable optimal crop yield are required. Among crop production, wheat is estimated to feed about one-fifth of humanity, but faces more and more drought stress periods, partially due to climate change. Plant growth promoting rhizobacteria are a promising and interesting way to develop productive and sustainable agriculture despite environmental stress. The current review focuses on drought stress effects on wheat and how plant growth-promoting rhizobacteria trigger drought stress tolerance of wheat by highlighting several mechanisms. These bacteria can lead to better growth and higher yield through the production of phytohormones, osmolytes, antioxidants, volatile compounds, exopolysaccharides and 1-aminocyclopropane-1-carboxylate deaminase. Based on the available literature, we provide a comprehensive review of mechanisms involved in drought resilience and how bacteria may alleviate this constraint

The Contrivance of Plant Growth Promoting Microbes to Mitigate Climate Change Impact in Agriculture

“…Excessive ROS accumulation in plant cells leads to numerous changes and damages, which in turn affect the condition of the plant, its yield and survival [83]. This could affect DNA, chlorophyll, enzymes and other proteins, which may lead to detrimental effects, and finally even cell death [20,[84][85][86]. To mitigate damage under this stress, plants have created complex antioxidative defense systems, in which involved are antioxidative enzymes and other non-enzymatic antioxidant mechanisms [6].…”

“…Klebsiella sp. IG 3 Wheat (Triticum aestivum L.) [20] Enhanced length and number of roots ACC deaminase and IAA production by bacteria. P. aeruginosa GGRJ21 Mung bean (Vigna radiata L.) [109] ACC deaminase production by bacteria.…”

“…The water requirements of plants depend on their stage of development. However some of them are particularly susceptible to water shortage, such as the grain-filling period or flowering [ 20 , 25 ]. Soil water shortage usually inhibits proper growth and development.…”

“…These situations endanger the plant by lowering enzymatic activity and decreasing water flux from xylem to the cells. This may inhibit mitosis, preventing the plant from growing [ 20 ]. Severe dehydration induces photorespiration as a result of both low CO 2 concentration and the unavailability of a sufficient amount of water.…”

“…Climate change is affecting the health of crops around the world [ 19 , 20 ]. This phenomenon is expected to worsen in the future, and there is a clear need to address this situation.…”