The astonishing increase in temperature presents an alarming threat to crop production worldwide. As evident by huge yield decline in various crops, the escalating drastic impacts of heat stress (HS) are putting global food production as well as nutritional security at high risk. HS is a major abiotic stress that influences plant morphology, physiology, reproduction, and productivity worldwide. The physiological and molecular responses to HS are dynamic research areas, and molecular techniques are being adopted for producing heat tolerant crop plants. In this article, we reviewed recent findings, impacts, adoption, and tolerance at the cellular, organellar, and whole plant level and reported several approaches that are used to improve HS tolerance in crop plants. Omics approaches unravel various mechanisms underlying thermotolerance, which is imperative to understand the processes of molecular responses toward HS. Our review about physiological and molecular mechanisms may enlighten ways to develop thermo-tolerant cultivars and to produce crop plants that are agriculturally important in adverse climatic conditions. 128 2 of 34 and osmotic adjustment and re-establish the redox balance of cell and homeostasis by modify the antioxidant system [10,11]. A plant in defense from HS causes modifications at the molecular level in the expression of genes [12]. In HS conditions, change in biochemical and physiological activities by gene expression alter gradually, resulting in the development of thermotolerance [13]. In order to successfully produce HS-tolerant crop varieties in the light of global climate change, there is need of knowledge and investigations about HS-tolerance mechanisms at physiological, biochemical, and molecular levels.At present, investigations into selection strategy and breeding for thermotolerant cultivars and understanding of heat tolerance mechanisms are more required today than ever before. Molecular and genetic mechanisms for avoiding HS-induced harmful changes play a crucial role in plant survival under such circumstances. In the present scenario of global warming, the major challenge for plant scientists is to develop new crop varieties tolerant to HS [14]. In the coming years, agricultural production will have to deal with growing crops under sub-optimal conditions accompanied by increased food demand, creating a gap between the current yield achievements and yield potential [15]. Developing genetically modified plants through target genes manipulation, QTLs, and omics techniques are widely studied molecular approaches in recent years. Our study about sensitivity, adaptations, mechanisms, and approaches may uncover ways to develop thermo-tolerant cultivars and to produce crop plants that are agriculturally important in adverse climatic conditions. Plant Sensitivity to Heat StressPlant sensitivity to HS varies with duration, plant type, and the degree of temperature. Plant growth and development are greatly influenced by the series of morphological, physiological, and biochemical changes resul...

No abstract

Summary Seed yield, determined mainly by seed numbers and seed weight, is the primary target of soybean breeding. Identifying the genes underlying yield‐related traits is of great significance. Through joint linkage mapping and a genome‐wide association study for 100‐seed weight, we cloned GmGA3ox1, a gene encoding gibberellin 3β‐hydroxylase, which is the key enzyme in the gibberellin synthesis pathway. Genome resequencing identified a beneficial GmGA3ox1 haplotype contributing to high seed weight, which was further confirmed by soybean transformants. CRISPR/Cas9‐generated gmga3ox1 mutants showed lower seed weight, but promoted seed yield by increasing seed numbers. The gmga3ox1 mutants reduced gibberellin biosynthesis while enhancing photosynthesis. Knockout of GmGA3ox1 resulted in the upregulation of numerous photosynthesis‐related genes, particularly the GmRCA family encoding ribulose‐1,5‐bispho‐sphate carboxylase‐oxygenase (Rubisco) activases. The basic leucine zipper transcription factors GmbZIP97 and GmbZIP159, which were both upregulated in the gmga3ox1 mutants and induced by the gibberellin synthesis inhibitor uniconazole, could bind to the promoter of GmRCAβ and activate its expression. Analysis of genomic sequences with over 2700 soybean accessions suggested that GmGA3ox1 is being gradually utilized in modern breeding. Our results elucidated the important role of GmGA3ox1 in soybean yield. These findings reveal important clues for future high‐yield breeding in soybean and other crops.

No abstract

No abstract