Like other abiotic stresses, salt stress has become a major factor that restricts the growth, distribution and yield of crops. Research has shown that increasing the nitrogen content in soil can improve the salt tolerance of plants and nitrate transporter (NRT) is the primary nitrogen transporter in plants. Suaeda salsa (L.) Pall is a strong halophyte that can grow normally at a salt concentration of 200 mM. The salt stress transcriptome database of S. salsa was found to contain four putative genes that were homologous to NRT, including SsNRT1.1A, SsNRT1.1B, SsNRT1.1C and SsNRT1.1D. The cDNA of SsNRT1.1s was predicted to contain open reading frames of 1791, 1782, 1755 and 1746 bp, respectively. Sequence alignment and structural analysis showed that the SsNRT1.1 amino acids were inducible by salt and have conserved MFS and PTR2 domains. Subcellular localization showed they are on the endoplasmic reticulum. Overexpression of SsNRT1.1 genes in transgenic Arabidopsis improves its salt tolerance and SsNRT1.1C was more effective than others. We constructed a salt-stressed yeast cDNA library and used yeast two-hybrid and BiFC technology to find out that SsHINT1 and SsNRT1.1C have a protein interaction relationship. Overexpression of SsHINT1 in transgenic Arabidopsis also improves salt tolerance and the expressions of Na⁺ and K⁺ were increased and reduced, respectively. But the K⁺/Liratio was up-regulated 11.1-fold compared with the wild type. Thus, these results provide evidence that SsNRT1.1C through protein interactions with SsHINT1 increases the K⁺/Na⁺ ratio to improve salt tolerance and this signaling may be controlled by the salt overly sensitive (SOS) pathway.

LEA_2 proteins are intrinsically disordered proteins implicated in plant abiotic stress tolerance; however, their functional characterization under salt and osmotic stress, particularly regarding stress-inducible peripheral redistribution, remains limited. SiLEA_2-6, an LEA_2 protein from the extreme-cold-tolerant species Saussurea involucrata, was identified from a cold-stress cDNA library, but its role in salt and osmotic tolerance remains unknown. In the present study, transgenic Arabidopsis thaliana Col-0 lines constitutively overexpressing SiLEA_2-6–eGFP were generated. Overexpression significantly enhanced salt and osmotic tolerance across germination, vegetative, and reproductive stages, as evidenced by improved germination rates, root elongation, survival, and physiological performance. Physiological analyses revealed improved membrane integrity (REL and MDA accumulation), enhanced osmotic adjustment, and preserved chlorophyll content. Subcellularly, SiLEA_2-6–eGFP displayed diffuse cytoplasmic distribution with intracellular punctate structures under non-stress conditions; within 60 min of salt or osmotic stress, it showed pronounced peripheral association, notably at guard cells and stomatal-adjacent regions. These findings demonstrate that SiLEA_2-6 enhances salt and osmotic tolerance in Arabidopsis, with stress-inducible peripheral enrichment consistent with a potential membrane-associated protective function. This study adds to the growing evidence that LEA_2 proteins confer tolerance not only to cold/freezing but also to salt and osmotic stress.

The nitrate signaling core regulator NLP7 is known to negatively regulate salt tolerance in Arabidopsis thaliana, but the function of the (SsNLP7A) gene in the halophyte Suaeda salsa remains unclear. To investigate whether SsNLP7A participates in salt stress responses, this study heterologously overexpressed the gene in tomato (Solanum lycopersicum) and systematically evaluated its function under salt stress through phenotypic, physiological, and transcriptomic analyses. The results indicate that SsNLP7A overexpression significantly promotes tomato root development and alleviates growth inhibition caused by salt stress. Under salt treatment, transgenic plants exhibited significantly higher chlorophyll content, accumulation of osmotic regulators (proline and soluble sugars), and antioxidant enzyme (POD, CAT, SOD) activity compared to wild-type plants. Transcriptome analysis further revealed that SsNLP7A enhances salt tolerance by regulating carbon metabolism, phytohormone signaling pathway, photosynthesis, and antioxidant pathways. Collectively, this study elucidates the positive regulatory role of SsNLP7A in salt stress response, providing new insights into its molecular mechanisms.

Low temperature is a major constraint limiting the productivity and distribution of crops, and aquaporins have emerged as important determinants of plant stress tolerance. Saussurea involucrata, an alpine plant adapted to extreme low-temperature environments, provides a valuable source of cold-tolerance genes, yet the contribution of its PIP1-type plasma membrane aquaporins to freezing and chilling tolerance in heterologous systems has not been established. Here, we isolated SiPIP1;5b, a PIP1-type plasma membrane intrinsic protein from S. involucrata, and constitutively overexpressed it in Arabidopsis thaliana and tomato (Solanum lycopersicum). Under freezing treatment (−4 °C, 4 h), SiPIP1;5b-overexpressing Arabidopsis lines showed markedly higher survival rates (72.0–81.5%) than the wild type (36.2%), together with lower relative electrolyte leakage and malondialdehyde (MDA) content and higher chlorophyll content. Under chilling stress (0 °C, 4 h), transgenic tomato plants likewise exhibited reduced electrolyte leakage and MDA accumulation, elevated activities of superoxide dismutase, catalase, and peroxidase, and increased proline content relative to wild-type plants. These results indicate that SiPIP1;5b enhances freezing and chilling tolerance and is associated with improved membrane stability, reduced accumulation of excessive reactive oxygen species, and enhanced antioxidant and osmoprotective responses. Our findings establish SiPIP1;5b as a promising candidate gene for improving low-temperature tolerance in crops.

Improving cotton yield without sacrificing fiber quality remains a major breeding challenge. In this study, a carpel-specific RNA interference construct targeting GhCKX3b was introduced into the elite upland cotton cultivar ‘Yuanmian 8’, which has high fiber quality but relatively low lint percentage. We evaluated the effects of this construct on cytokinin accumulation, yield-related traits, and fiber quality across T0, T1, and T2 generations. Carpel-specific suppression of GhCKX3b increased cytokinin content in T2 positive lines by 50.3% to 102.0% relative to wild-type. Transgenic lines consistently showed increased lint percentage, boll weight, and seeds per boll, while seed index decreased moderately. In the best-performing line, lint percentage increased from 36.4% to 45.8%, and boll weight from 6.30 g to 7.31 g. Multi-year field evaluations confirmed stable inheritance of these improvements across generations. Importantly, major fiber quality parameters—including length, strength, and micronaire—remained within high-quality cotton standards. These results indicate that carpel-specific GhCKX3b suppression effectively improves key yield components in a high-quality cotton background without compromising fiber quality. This study provides breeding-oriented evidence supporting the application of tissue-specific cytokinin regulation in cotton improvement.