Wheat is an important cereal crop species consumed globally. The growing global population demands a rapid and sustainable growth of agricultural systems. The development of genetically efficient wheat varieties has solved the global demand for wheat to a greater extent. The use of chemical substances for pathogen control and chemical fertilizers for enhanced agronomic traits also proved advantageous but at the cost of environmental health. An efficient alternative environment-friendly strategy would be the use of beneficial microorganisms growing on plants, which have the potential of controlling plant pathogens as well as enhancing the host plant’s water and mineral availability and absorption along with conferring tolerance to different stresses. Therefore, a thorough understanding of plant-microbe interaction, identification of beneficial microbes and their roles, and finally harnessing their beneficial functions to enhance sustainable agriculture without altering the environmental quality is appealing. The wheat microbiome shows prominent variations with the developmental stage, tissue type, environmental conditions, genotype, and age of the plant. A diverse array of bacterial and fungal classes, genera, and species was found to be associated with stems, leaves, roots, seeds, spikes, and rhizospheres, etc., which play a beneficial role in wheat. Harnessing the beneficial aspect of these microbes is a promising method for enhancing the performance of wheat under different environmental stresses. This review focuses on the microbiomes associated with wheat, their spatio-temporal dynamics, and their involvement in mitigating biotic and abiotic stresses.
15 February 2020 in Journal of Experimental Botany
As a plant hormone, salicylic acid (SA) plays essential roles in plant defense against biotrophic and hemibiotrophic pathogens. Significant progress has been made in understanding the SA biosynthesis pathways and SA-mediated defense signaling networks in the past two decades. Plant defense responses involve rapid and massive transcriptional reprogramming upon the recognition of pathogens. Plant transcription factors and their co-regulators are critical players in establishing a transcription regulatory network and boosting plant immunity. A multitude of transcription factors and epigenetic regulators have been discovered, and their roles in SA-mediated defense responses have been reported. However, our understanding of plant transcriptional networks is still limited. As such, novel genomic tools and bioinformatic techniques will be necessary if we are to fully understand the mechanisms behind plant immunity. Here, we discuss current knowledge, provide an update on the SA biosynthesis pathway, and describe the transcriptional and epigenetic regulation of SA-mediated plant immune responses.
Salicylic acid (SA) plays pivotal role in plant defense against biotrophic and hemibiotrophic pathogens. Tremendous progress has been made in the field of SA biosynthesis and SA signaling pathways over the past three decades. Among the key immune players in SA signaling pathway, NONEXPRESSOR OF PATHOGENESIS‐RELATED GENES1 (NPR1) functions as a master regulator of SA‐mediated plant defense. The function of NPR1 as an SA receptor has been controversial; however, after years of arguments among several laboratories, NPR1 has finally been proven as one of the SA receptors. The function of NPR1 is strictly regulated via post‐translational modifications and transcriptional regulation that were recently found. More recent advances in NPR1 biology, including novel functions of NPR1 and the structure of SA receptor proteins, have brought this field forward immensely. Therefore, based on these recent discoveries, this review acts to provide a full picture of how NPR1 functions in plant immunity and how NPR1 gene and NPR1 protein are regulated at multiple levels. Finally, we also discuss potential challenges in future studies of SA signaling pathway.
Plants being sessile in nature, are exposed to unwarranted threats as a result of constantly changing environmental conditions. These adverse factors can have negative impacts on their growth, development, and yield. Hormones are key signaling molecules enabling cells to respond rapidly to different external and internal stimuli. In plants, melatonin (MT) plays a critical role in the integration of various environmental signals and activation of stress-response networks to develop defense mechanisms and plant resilience. Additionally, melatonin can tackle the stress-induced alteration of cellular redox equilibrium by regulating the expression of redox hemostasis-related genes and proteins. The purpose of this article is to compile and summarize the scientific research pertaining to MT's effects on plants' resilience to biotic and abiotic stresses. Here, we have summarized that MT exerts a synergistic effect with other phytohormones, for instance, ethylene, jasmonic acid, and salicylic acid, and activates plant defense-related genes against phytopathogens. Furthermore, MT interacts with secondary messengers like Ca2+, nitric oxide, and reactive oxygen species to regulate the redox network. This interaction triggers different transcription factors to alleviate stress-related responses in plants. Hence, the critical synergic role of MT with diverse plant hormones and secondary messengers demonstrates phytomelatonin's importance in influencing multiple mechanisms to contribute to plant resilience against harsh environmental factors.
Climate change, driven by human activities and natural processes, has led to critical alterations in varying patterns during cropping seasons and is a vital threat to global food security. The climate change impose several abiotic stresses on crop production systems. These abiotic stresses include extreme temperatures, drought, and salinity, which expose agricultural fields to more vulnerable conditions and lead to substantial crop yield and quality losses. Plant hormones, especially salicylic acid (SA), has crucial roles for plant resiliency under unfavorable environments. This review explores the genetics and molecular mechanisms underlying SA's role in mitigating abiotic stress-induced damage in plants. It also explores the SA biosynthesis pathways, and highlights the regulation of their products under several abiotic stresses. Various roles and possible modes of action of SA in mitigating abiotic stresses are discussed, along with unraveling the genetic mechanisms and genes involved in responses under stress conditions. Additionally, this review investigates molecular pathways and mechanisms through which SA exerts its protective effects, such as redox signaling, cross-talks with other plant hormones, and mitogen-activated protein kinase pathways. Moreover, the review discusses potentials of using genetic engineering approaches, such as CRISPR technology, for deciphering the roles of SA in enhancing plant resilience to climate change related abiotic stresses. This comprehensive analysis bridges the gap between genetics of SA role in response to climate change related stressors. Overall goal is to highlight SA's significance in safeguarding plants and by offering insights of SA hormone for sustainable agriculture under challenging environmental conditions.
Biotic and abiotic stresses negatively affect the yield and overall plant developmental process, thus causing substantial losses in global sweet potato production. To cope with stresses, sweet potato has evolved numerous strategies to tackle ever-changing surroundings and biological and environmental conditions. The invention of modern sequencing technology and the latest data processing and analysis instruments has paved the way to integrate biological information from different approaches and helps to understand plant system biology more precisely. The advancement in omics technologies has accumulated and provided a great source of information at all levels (genome, transcript, protein, and metabolite) under stressful conditions. These latest molecular tools facilitate us to understand better the plant’s responses to stress signaling and help to process/integrate the biological information encoded within the biological system of plants. This review briefly addresses utilizing the latest omics strategies for deciphering the adaptive mechanisms for sweet potatoes’ biotic and abiotic stress tolerance via functional genomics, transcriptomics, proteomics, and metabolomics. This information also provides a powerful reference to understand the complex, well-coordinated stress signaling genetic regulatory networks and better comprehend the plant phenotypic responses at the cellular/molecular level under various environmental stimuli, thus accelerating the design of stress-resilient sweet potato via the latest genetic engineering approaches.