The significant rise in soil salinity has had detrimental effects on global agricultural production, negatively impacting overall plant health and leading to a decline in productivity. As a protective response, plants have developed diverse regulatory mechanisms to counteract these adverse conditions. The mechanisms help mitigate damage caused by both osmotic and ionic stress resulting from high salinity. Given the severe threat this poses to global food security and the well-being of the world's population, scientists have dedicated decades of research to understanding how to manage salt stress. Numerous mechanisms have been identified and studied to enhance plant salt tolerance and alleviate the damage caused by salt stress. This review examines recent advancements in molecular regulatory mechanisms underlying plant salt, including salt uptake and transport, salt sensing and signalling, hormonal regulation, epigenetic modifications, genetic adaptation, and posttranslational modifications. Although current knowledge has advanced our understanding, critical gaps and controversies remain, such as the stability of epigenetic memory, the trade-off between stress tolerance and growth, hormonal crosstalk, and novel genes with uncharacterised roles in salt tolerance. To resolve these questions, further research employing techniques like GWAS, transcriptomics, transgenic and genome-editing technologies, as well as studies on energy allocation and hormonal regulation, is essential. A deeper exploration of these complex, synergistic mechanisms will pave the way for enhancing plant resilience and ensuring adaptation to increasingly challenging environmental conditions.

This study aimed to examine the effects of aluminum (Al) stress on the leaves of Shatian pomelo (Citrus maxima Shatian Yu) and its underlying response mechanisms. Leaf phenotype analysis, physiological response index determination, transcriptome analysis, and genome verification were employed to investigate the effects of Al toxicity in detail. Al toxicity stress inhibited leaf growth and development, reducing leaf area, girth, and both dry and fresh weights. Antioxidant enzyme activity and soluble protein content in leaves significantly increased with rising Al stress levels. Additionally, Al toxicity caused an accumulation of Al ions in leaves and a decline in boron, magnesium, calcium, manganese, and iron ion content. RNA sequencing identified 4868 differentially expressed genes (DEGs) under 0 mM (Control) and 4 mM (Al stress) conditions, with 1994 genes upregulated and 2874 downregulated, indicating a complex molecular regulatory response. These findings were further validated by real-time quantitative PCR (qPCR). The results provide critical insights into the molecular mechanisms of Shatian pomelo leaf response to Al toxicity and offer a theoretical basis and practical guidance for improving citrus productivity in acidic soils.

Main conclusion gamma-Aminobutyric acid alleviates acid-aluminum toxicity to roots associated with enhanced antioxidant metabolism as well as accumulation and transportation of citric and malic acids.AbstractAluminum (Al) toxicity has become the main limiting factor for crop growth and development in acidic soils and is further being aggravated worldwide due to continuous industrial pollution. The current study was designed to examine effects of GABA priming on alleviating acid-Al toxicity in terms of root growth, antioxidant defense, citrate and malate metabolisms, and extensive metabolites remodeling in roots under acidic conditions. Thirty-seven-day-old creeping bentgrass (Agrostis stolonifera) plants were used as test materials. Roots priming with or without 0.5 mM GABA for 3 days were cultivated in standard nutrient solution for 15 days as control or subjected to nutrient solution containing 5 mM AlCl36H2O for 15 days as acid-Al stress treatment. Roots were sampled for determinations of root characteristics, physiological and biochemical parameters, and metabolomics. GABA priming significantly alleviated acid-Al-induced root growth inhibition and oxidative damage, despite it promoted the accumulation of Al in roots. Analysis of metabolomics showed that GABA priming significantly increased accumulations of organic acids, amino acids, carbohydrates, and other metabolites in roots under acid-Al stress. In addition, GABA priming also significantly up-regulated key genes related to accumulation and transportation of malic and citric acids in roots under acid-Al stress. GABA-regulated metabolites participated in tricarboxylic acid cycle, GABA shunt, antioxidant defense system, and lipid metabolism, which played positive roles in reactive oxygen species scavenging, energy conversion, osmotic adjustment, and Al ion chelation in roots.

Cadmium (Cd) is a highly toxic heavy metal that causes serious damage to plant and human health. Phytolacca acinosa Roxb. has a large amount of aboveground biomass and a rapid growth rate, and it has been identified as a novel type of Cd hyperaccumulator that can be harnessed for phytoremediation. However, the molecular mechanisms underlying the response of P. acinosa to Cd2+ stress remain largely unclear. In this study, the phenotype, biochemical, and physiological traits of P. acinosa seeds and seedlings were analyzed under different concentrations of Cd2+ treatments. The results showed higher Cd2+ tolerance of P. acinosa compared to common plants. Meanwhile, the Cd2+ content in shoots reached 449 mg/kg under 10 mg/L Cd2+ treatment, which was obviously higher than the threshold for Cd hyperaccumulators. To investigate the molecular mechanism underlying the adaptability of P. acinosa to Cd stress, RNA-Seq was used to examine transcriptional responses of P. acinosa to Cd stress. Transcriptome analysis found that 61 genes encoding TFs, 48 cell wall-related genes, 35 secondary metabolism-related genes, 133 membrane proteins and ion transporters, and 96 defense system-related genes were differentially expressed under Cd2+ stress, indicating that a series of genes were involved in Cd2+ stress, forming a complex signaling regulatory mechanism. These results provide new scientific evidence for elucidating the regulatory mechanisms of P. acinosa response to Cd2+ stress and new clues for the molecular breeding of heavy metal phytoremediation.