Rice (Oryza sativa) is one of the most important crops grown worldwide, and saline–alkali stress seriously affects the yield and quality of rice. It is imperative to elucidate the molecular mechanisms underlying rice response to saline–alkali stress. In this study, we conducted an integrated analysis of the transcriptome and metabolome to elucidate the effects of long-term saline–alkali stress on rice. High saline–alkali stress (pH > 9.5) induced significant changes in gene expression and metabolites, including 9347 differentially expressed genes (DEGs) and 693 differentially accumulated metabolites (DAMs). Among the DAMs, lipids and amino acids accumulation were greatly enhanced. The pathways of the ABC transporter, amino acid biosynthesis and metabolism, glyoxylate and dicarboxylate metabolism, glutathione metabolism, TCA cycle, and linoleic acid metabolism, etc., were significantly enriched with DEGs and DAMs. These results suggest that the metabolites and pathways play important roles in rice’s response to high saline–alkali stress. Our study deepens the understanding of mechanisms response to saline–alkali stress and provides references for molecular design breeding of saline–alkali resistant rice.

Saline and alkaline stresses limit plant growth and reduce crop yield. Soil salinization and alkalization seriously threaten the sustainable development of agriculture and the virtuous cycle of ecology. Biofertilizers made from plant growth−promoting rhizobacteria (PGPR) not only enhance plant growth and stress tolerance, but also are environmentally friendly and cost-effective. There have been many studies on the mechanisms underlying PGPRs enhancing plant salt resistance. However, there is limited knowledge about the interaction between PGPR and plants under alkaline–sodic stress. To clarify the mechanisms underlying PGPR’s improvement of plants’ tolerance to alkaline–sodic stress, we screened PGPR from the rhizosphere microorganisms of local plants growing in alkaline–sodic land and selected an efficient strain, Bacillus altitudinis AD13−4, as the research object. Our results indicate that the strain AD13−4 can produce various growth-promoting substances to regulate plant endogenous hormone levels, cell division and differentiation, photosynthesis, antioxidant capacity, etc. Transcriptome analysis revealed that the strain AD13−4 significantly affected metabolism and secondary metabolism, signal transduction, photosynthesis, redox processes, and plant–pathogen interactions. Under alkaline–sodic conditions, inoculation of the strain AD13−4 significantly improved plant biomass and the contents of metabolites (e.g., soluble proteins and sugars) as well as secondary metabolites (e.g., phenols, flavonoids, and terpenoids). The 16S rRNA gene sequencing results indicated that the strain AD13−4 significantly affected the abundance and composition of the rhizospheric microbiota and improved soil activities and physiochemical properties. Our study provides theoretical support for the optimization of saline–alkali-tolerant PGPR and valuable information for elucidating the mechanism of plant alkaline–sodic tolerance.

Saline-alkali stress seriously affects the yield and quality of crops, threatening food security and ecological security. Improving saline-alkali land and increasing effective cultivated land are conducive to sustainable agricultural development. Trehalose, a nonreducing disaccharide, is closely related to plant growth and development and stress response. Trehalose 6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP) are key enzymes catalyzing trehalose biosynthesis. To elucidate the effects of long-term saline-alkali stress on trehalose synthesis and metabolism, we conducted an integrated transcriptome and metabolome analysis. As a result, 13 TPS and 11 TPP genes were identified in quinoa (Chenopodium quinoa Willd.) and were named CqTPS1-13 and CqTPP1-11 according to the order of their Gene IDs. Through phylogenetic analysis, the CqTPS family is divided into two classes, and the CqTPP family is divided into three classes. Analyses of physicochemical properties, gene structures, conservative domains and motifs in the proteins, and cis-regulatory elements, as well as evolutionary relationships, indicate that the TPS and TPP family characteristics are highly conserved in quinoa. Transcriptome and metabolome analyses of the sucrose and starch metabolism pathway in leaves undergoing saline-alkali stress indicate that CqTPP and Class II CqTPS genes are involved in the stress response. Moreover, the accumulation of some metabolites and the expression of many regulatory genes in the trehalose biosynthesis pathway changed significantly, suggesting the metabolic process is important for the saline-alkali stress response in quinoa.

The escalating frequency and severity of drought events pose significant threats to agricultural productivity and food security. Drought stress not only restricts crop growth and yields but also destabilizes agricultural ecosystems. Over evolutionary timescales, plants have developed intricate adaptive strategies, encompassing drought escape (accelerated phenology), avoidance (water-conserving morphology) and tolerance (cellular protection), which involve complex biological mechanisms spanning molecular signaling, metabolic reprogramming and organ morphological remodeling. To mitigate drought risks, breeding drought-tolerant and water-efficient crops is imperative. Currently, drought resistance breeding is undergoing a paradigm shift, transitioning from traditional phenotypic selection toward genomics-assisted selection, molecular design and artificial intelligence (AI)-driven predictive modeling. This review provides a comprehensive analysis of drought stress response mechanisms in crops, integrating three key dimensions: physiological/biochemical adaptations, hormonal signaling networks and morphological/structural modifications. Furthermore, it critically evaluates recent advances in genetic improvement approaches for drought resistance, such as marker-assisted selection, transgenic technology and gene editing. It also explores the integration of multi-omics data and AI to enhance precision molecular breeding and overcome the inherent trade-off between drought resistance and yield potential. By synthesizing advancements in molecular breeding and smart agriculture, this work provides a roadmap for developing climate-resilient crops optimized through synergistic trait engineering and intelligent environmental sensing.

Soil saline–alkalization inhibits plant growth and development and seriously affects crop yields. Over their long-term evolution, plants have formed complex stress response systems to maintain species continuity. R2R3-MYB transcription factors are one of the largest transcription factor families in plants, widely involved in plant growth and development, metabolism, and stress response. Quinoa (Chenopodium quinoa Willd.), as a crop with high nutritional value, is tolerant to various biotic and abiotic stress. In this study, we identified 65 R2R3-MYB genes in quinoa, which are divided into 26 subfamilies. In addition, we analyzed the evolutionary relationships, protein physicochemical properties, conserved domains and motifs, gene structure, and cis-regulatory elements of CqR2R3-MYB family members. To investigate the roles of CqR2R3-MYB transcription factors in abiotic stress response, we performed transcriptome analysis to figure out the expression file of CqR2R3-MYB genes under saline–alkali stress. The results indicate that the expression of the six CqMYB2R genes was altered significantly in quinoa leaves that had undergone saline–alkali stress. Subcellular localization and transcriptional activation activity analysis revealed that CqMYB2R09, CqMYB2R16, CqMYB2R25, and CqMYB2R62, whose Arabidopsis homologues are involved in salt stress response, are localized in the nucleus and exhibit transcriptional activation activity. Our study provides basic information and effective clues for further functional investigation of CqR2R3-MYB transcription factors in quinoa.