Variability in morpho-biochemical, photosynthetic pigmentation, enzymatic and quality attributes of potato for salinity stress tolerance

Impact of boron on Glycine max L. to mitigate salt stress by modulating the morpho-physiological and biochemical responses

BACKGROUND

Boron (B) is an essential micronutrient in higher plants, contributing to various physiological processes. However, its protective mechanism in mitigating salt stress remained less understood. This study investigates that exogenous boron (0, 1, 2 kg ha- 1) can help alleviate salt stress (0, 60, 120 mM NaCl) in two soybean cultivars AARI-2021 (V1) and Ajmeri (V2). It examines B role in reactive oxygen species (ROS), secondary metabolites, and antioxidant defense systems in mitigating salt stress.

RESULTS

Salt stress negatively impacted morph-physiological and biochemical attributes. Boron supplementation (2 kg ha- 1) reduced oxidative stress indicators, such as malondialdehyde (by 18% in V1 and by 21% in V2) and hydrogen peroxide (by 30% in V1 and by 38% in V2). Moreover, foliar application of boron (2 kg ha- 1) increased the catalase (CAT) (58% in V1 and 57% in V2), superoxide dismutase (SOD) (7% in V1 and 10% in V2), and peroxidase (POD) (42% in V1 and 32% in V2) activities under salt stress. Salt stress also led to an increase in Na+ and a decrease in K+ and Ca2+. However, boron supplementation enhanced K+ and Ca2+ in salt-stressed plants. Furthermore, boron application (2 kg ha- 1) increased the activity of secondary metabolites, total phenols content (TPC) (by 52% in V1 and by 59% in V2), total flavonoid content (TFC) (by 27% in V1 and by 21% in V2), and anthocyanins (ANTs) (by 33% in V1 and by 25% in V2) under salt stress.

CONCLUSION

This study suggests that B can reduce salinity-induced oxidative damage in soybean plants by modifying antioxidant defense and secondary metabolites and preserving ion homeostasis.

Elucidating the molecular basis of salt tolerance in potatoes through miRNA expression and phenotypic analysis

Potatoes are a critical staple crop worldwide, yet their yield is significantly constrained by salt stress. Understanding and enhancing salt tolerance in potatoes is crucial for ensuring food security. This study evaluated the salt tolerance of 17 diverse potato varieties using principal component analysis, membership function analysis, cluster analysis, and stepwise regression analysis. Comprehensive evaluation based on morphological, physiological, and biochemical indicators divided the varieties into three categories, identifying Z1264-1, Z700-1, Z943-1, Z1266-1, Z510-1, and Z1076-1 as having strong salt tolerance. Regression equations established stem thickness, root length, and catalase activity as rapid identification markers for salt tolerance in tetraploid potatoes. Transcriptome analysis of the highly tolerant variety Z1076-1 identified 68 differentially expressed miRNAs (DE miRNAs). qRT-PCR validation for eight randomly selected DE miRNAs confirmed consistent expression trends with transcriptome data. Predicted target genes of these miRNAs are involved in calcium channel signaling, osmotic regulation, plant hormone signaling, and reactive oxygen species clearance. Our findings provide valuable insights for the identification and screening of salt-tolerant potato germplasms. The findings also lay the foundation for studying molecular mechanisms of salt tolerance and advancing genetic breeding efforts to cultivate more resilient potato varieties.

Arbuscular mycorrhizal fungi communities and promoting the growth of alfalfa in saline ecosystems of northern China

Arbuscular mycorrhizal fungi (AMF) are universally distributed in soils, including saline soils, and can form mycorrhizal symbiosis with the vast majority of higher plants. This symbiosis can reduce soil salinity and influence plant growth and development by improving nutrient uptake, increasing plant antioxidant enzyme activity, and regulating hormone levels. In this study, rhizosphere soil from eight plants in the Songnen saline-alkaline grassland was used to isolate, characterize, and screen the indigenous advantageous AMF. The promoting effect of AMF on alfalfa (Medicago sativa L.) under salt treatment was also investigated. The findings showed that 40 species of AMF in six genera were identified by high-throughput sequencing. Glomus mosseae (G.m) and Glomus etunicatum (G.e) are the dominant species in saline ecosystems of northern China. Alfalfa inoculated with Glomus mosseae and Glomus etunicatum under different salt concentrations could be infested and form a symbiotic system. The mycorrhizal colonization rate and mycorrhizal dependence of G.m inoculation were significantly higher than those of G.e inoculation. With increasing salt concentration, inoculation increased alfalfa plant height, fresh weight, chlorophyll content, proline (Pro), soluble sugar (SS), soluble protein (SP), peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activity while decreasing the malondialdehyde (MDA) content and superoxide anion production rate. The results highlight that inoculation with G.m and G.e effectively alleviated salinity stress, with G.m inoculation having a significant influence on salt resistance in alfalfa. AMF might play a key role in alfalfa growth and survival under harsh salt conditions.

Overexpression of the potato VQ31 enhances salt tolerance in Arabidopsis

Plant-specific VQ proteins have crucial functions in the regulation of plant growth and development, as well as in plant abiotic stress responses. Their roles have been well established in the model plant Arabidopsis thaliana; however, the functions of the potato VQ proteins have not been adequately investigated. The VQ protein core region contains a short FxxhVQxhTG amino acid motif sequence. In this study, the VQ31 protein from potato was cloned and functionally characterized. The complete open reading frame (ORF) size of StVQ31 is 672 bp, encoding 223 amino acids. Subcellular localization analysis revealed that StVQ31 is located in the nucleus. Transgenic Arabidopsis plants overexpressing StVQ31 exhibited enhanced salt tolerance compared to wild-type (WT) plants, as evidenced by increased root length, germination rate, and chlorophyll content under salinity stress. The increased tolerance of transgenic plants was associated with increased osmotic potential (proline and soluble sugars), decreased MDA accumulation, decreased total protein content, and improved membrane integrity. These results implied that StVQ31 overexpression enhanced the osmotic potential of the plants to maintain normal cell growth. Compared to the WT, the transgenic plants exhibited a notable increase in antioxidant enzyme activities, reducing cell membrane damage. Furthermore, the real-time fluorescence quantitative PCR analysis demonstrated that StVQ31 regulated the expression of genes associated with the response to salt stress, including ERD, LEA4-5, At2g38905, and AtNCED3. These findings suggest that StVQ31 significantly impacts osmotic and antioxidant cellular homeostasis, thereby enhancing salt tolerance.