PDF(Pubmed)
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.
摘要：
盐胁迫直接影响植物的生长。叶片生长的限制是盐胁迫最早可见的影响之一。然而,盐处理对叶片形状的调节机制尚未完全阐明。我们测量了形态特征和解剖结构。结合转录组分析，我们分析了差异表达基因（DEGs），并通过qRT-PCR验证了RNA-seq数据。最后,我们分析了叶片微观结构参数与expansin基因的相关性。我们证明了叶子的厚度，宽度,盐胁迫7天后，盐浓度升高，叶片长度显着增加。低盐主要促进叶片长度和宽度的增加，但是高盐浓度会加速叶片厚度。解剖结构结果表明，栅栏叶肉组织比海绵状叶肉组织对叶片厚度的贡献更大。这可能有助于叶片膨胀和厚度的增加。此外，通过RNA-seq鉴定了总共3,572个DEGs。值得注意的是,在92个鉴定的基因中，有6个DEGs集中在细胞壁合成或修饰上，与细胞壁松动蛋白有关。更重要的是,我们证明，上调的EXLA2基因与barbarum叶片栅栏组织的厚度之间存在很强的正相关。这些结果表明盐胁迫可能诱导了EXLA2基因的表达,通过促进栅栏组织细胞的纵向扩张，从而增加了L.barbarum叶片的厚度。这项研究为揭示L.barbarum响应盐胁迫而叶片增厚的潜在分子机制奠定了坚实的知识。
