Changes in the morphology traits, anatomical structure of the leaves and transcriptome in Lycium barbarum L. under salt stress

Abstract

Salt stress directly affects the growth of plants. The limitation of leaf grow is among the earliest visible effects of salt stress. However, the regulation mechanism of salt treatments on leaf shape has not been fully elucidated. We measured the morphological traits and anatomical structure. In combination with transcriptome analysis, we analyzed differentially expressed genes (DEGs) and verified the RNA-seq data by qRT-PCR. Finally, we analyzed correlation between leaf microstructure parameters and expansin genes. We show that the leaf thickness, the width, and the leaf length significantly increased at elevated salt concentrations after salt stress for 7 days. Low salt mainly promoted the increase in leaves length and width, but high salt concentration accelerated the leaf thickness. The anatomical structure results indicated that palisade mesophyll tissues contribute more to leaf thickness than spongy mesophyll tissues, which possibly contributed to the increase in leaf expansion and thickness. Moreover, a total of 3,572 DEGs were identified by RNA-seq. Notably, six of the DEGs among 92 identified genes concentrated on cell wall synthesis or modification were involved in cell wall loosening proteins. More importantly, we demonstrated that there was a strong positive correlation between the upregulated EXLA2 gene and the thickness of the palisade tissue in L. barbarum leaves. These results suggested that salt stress possibly induced the expression of EXLA2 gene, which in turn increased the thickness of L. barbarum leaves by promoting the longitudinal expansion of cells of the palisade tissue. This study lays a solid knowledge for revealing the underlying molecular mechanisms of leaf thickening in L. barbarum in response to salt stresses.

Chromosome Doubling Enhances Biomass and Carotenoid Content in Lycium chinense

“…This increase in chlorophyll content following polyploidization was also noted in Lilium [54]. Given its high sensitivity to environmental conditions, the microstructure of the leaf can potentially indicate a plant's adaptability to environmental conditions [55]. Compared to diploid plants, the tetraploid plants exhibited thicker leaf veins and palisade tissues, a higher ratio of palisade to spongy tissue, and increased water content.…”

PacBio Full-Length Transcriptome Sequencing Reveals the Mechanism of Salt Stress Response in Sonneratia apetala

“…Salt stress could limit leaf growth by inhibiting cell elongation and limiting cellulose synthesis. When plants are exposed to salt stress, their cell walls undergo a series of physiological changes, such as an increase in thickness and alterations in integrity [62]. These changes enhance the stability and elasticity of the cell wall, thereby improving a plant's ability to adapt to salt stress.…”

“…Moreover, polysaccharides in the cell wall, such as cellulose and pectin, can also serve as signaling molecules that participate in internal signal transduction and regulation in response to salt stress [63]. Shen et al [62,64] demonstrated that the periderm tissues of the two Glycyrrhiza species (Glycyrrhiza uralensis and Glycyrrhiza inflata) are thickened under salt stress to maintain normal plant metabolism. Yao et al [62] identified 92 DEGs related to cell wall synthesis or modification in Lycium barbarum under salt stress using Illumina high-throughput sequencing.…”

“…Shen et al [62,64] demonstrated that the periderm tissues of the two Glycyrrhiza species (Glycyrrhiza uralensis and Glycyrrhiza inflata) are thickened under salt stress to maintain normal plant metabolism. Yao et al [62] identified 92 DEGs related to cell wall synthesis or modification in Lycium barbarum under salt stress using Illumina high-throughput sequencing. Cellulose synthase (CESA) and callose synthase (Cals) are important enzymes in cell wall and callose synthesis, respectively [65].…”

Unleashing the Power of Fungi: Utilizing the Arbuscular Mycorrhizal Fungi Rhizophagus clarus to Mitigate Salinity Stress and Boost Cowpea Bean Productivity for Food Security

“…Anatomically, salinity stress induces alterations in leaf structure and cellular organization. Leaves exposed to high salt concentrations may exhibit reduced leaf thickness, chloroplast disorganization, and impaired photosynthetic capacity [11,12]. Moreover, salinity stress can disrupt vascular tissue integrity, impairing nutrient and water transport within the plant.…”