Transcriptomics analysis of field-droughted pear (Pyrus spp.) reveals potential drought stress genes and metabolic pathways

Multiomics Analyses Reveal MsC3H29 Positively Regulates Flavonoid Biosynthesis to Improve Drought Resistance of Autotetraploid Cultivated Alfalfa (Medicago sativa L.)

Alfalfa (Medicago sativa subsp. sativa), the "queen of forage," is the most important perennial legume, with high productivity and an excellent nutritional profile. Medicago sativa subsp. falcata is a subspecies of the alfalfa complex and exhibits better drought tolerance. However, drought stress significantly hampers their development and yield. The molecular mechanisms underlying the aboveground and underground tissues of sativa and falcata responding to drought stress remain obscure. Here, we performed a comprehensive comparative analysis of the physiological and transcriptomic responses of sativa and falcata under drought stress. The results showed that photosynthesis was inhibited, and antioxidant enzymes were activated under drought stress. MsC3H29, a CCCH-type zinc finger protein, was identified as a hub gene through weighted gene coexpression network analysis (WGCNA) and was significantly induced by drought in underground tissue. The MsC3H29 protein was localized in the nucleus. Overexpression (OE) of MsC3H29 can increase the primary root length and fresh weight of transgenic alfalfa hairy roots, while RNA interference (RNAi) decreases them under drought stress. The 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA) staining revealed that MsC3H29 promoted drought tolerance of alfalfa hairy roots through decreasing ROS accumulation. The targeted metabolome analysis showed that the overexpression of MsC3H29 resulted in higher levels of accumulation for flavonoid monomers, including vicenin, daidzein, apigenin, isorhamnetin, quercetin, and tricin, in transgenic alfalfa hairy roots before and after drought stress, while RNAi led to a reduction. Our study provided a key candidate gene for molecular breeding to improve drought resistance in alfalfa.

Orchard Management and Incorporation of Biochemical and Molecular Strategies for Improving Drought Tolerance in Fruit Tree Crops

Water scarcity is one of the greatest concerns for agronomy worldwide. In recent years, many water resources have been depleted due to multiple factors, especially mismanagement. Water resource shortages lead to cropland expansion, which likely influences climate change and affects global agriculture, especially horticultural crops. Fruit yield is the final aim in commercial orchards; however, drought can slow tree growth and/or decrease fruit yield and quality. It is therefore necessary to find approaches to solve this problem. The main objective of this review is to discuss the most recent horticultural, biochemical, and molecular strategies adopted to improve the response of temperate fruit crops to water stress. We also address the viability of cultivating fruit trees in dry areas and provide precise protection methods for planting fruit trees in arid lands. We review the main factors involved in planting fruit trees in dry areas, including plant material selection, regulated deficit irrigation (DI) strategies, rainwater harvesting (RWH), and anti-water stress materials. We also provide a detailed analysis of the molecular strategies developed to combat drought, such as Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) through gene overexpression or gene silencing. Finally, we look at the molecular mechanisms associated with the contribution of the microbiome to improving plant responses to drought.

Comparative Transcriptome Analysis of Tolerant and Sensitive Genotypes of Common Bean (Phaseolus vulgaris L.) in Response to Terminal Drought Stress

We conducted a genome-wide transcriptomic analysis of three drought tolerant and sensitive genotypes of common bean to examine their transcriptional responses to terminal drought stress. We then conducted pairwise comparisons between the root and leaf transcriptomes from the resulting tissue based on combined transcriptomic data from the tolerant and sensitive genotypes. Our transcriptomic data revealed that 491 (6.4%) DEGs (differentially expressed genes) were upregulated in tolerant genotypes, whereas they were downregulated in sensitive genotypes; likewise, 396 (5.1%) DEGs upregulated in sensitive genotypes were downregulated in tolerant genotypes. Several transcription factors, heat shock proteins, and chaperones were identified in the study. Several DEGs in drought DB (data Base) overlapped between genotypes. The GO (gene ontology) terms for biological processes showed upregulation of DEGs in tolerant genotypes for sulfate and drug transmembrane transport when compared to sensitive genotypes. A GO term for cellular components enriched with upregulated DEGs for the apoplast in tolerant genotypes. These results substantiated the temporal pattern of root growth (elongation and initiation of root growth), and ABA-mediated drought response in tolerant genotypes. KEGG (kyoto encyclopedia of genes and genomes) analysis revealed an upregulation of MAPK (mitogen activated protein kinase) signaling pathways and plant hormone signaling pathways in tolerant genotypes. As a result of this study, it will be possible to uncover the molecular mechanisms of drought tolerance in response to terminal drought stress in the field. Further, genome-wide transcriptomic analysis of both tolerant and sensitive genotypes will assist us in identifying potential genes that may contribute to improving drought tolerance in the common bean.