Abstract

Hydrogen sulfide (H₂S) is known to have positive physiological functions in plant growth, but limited data are available on its influence on cell walls. Here, we demonstrate a novel mechanism by which H₂S regulates the biosynthesis and deposition of cell wall cellulose in alfalfa (Medicago sativa). Treatment with NaHS was found to increase the length of epidermal cells in the hypocotyl, and transcriptome analysis indicated that it caused the differential expression of numerous of cell wall-related genes. These differentially expressed genes were directly associated with the biosynthesis of cellulose and hemicellulose, and with the degradation of pectin. Analysis of cell wall composition showed that NaHS treatment increased the contents of cellulose and hemicellulose, but decreased the pectin content. Atomic force microscopy revealed that treatment with NaHS decreased the diameter of cellulose fibrils, altered the arrangement of the fibrillar bundles, and increased the spacing between the bundles. The dynamics of cellulose synthase complexes (CSCs) were closely related to cellulose synthesis, and NaHS increased the rate of mobility of the particles. Overall, our results suggest that the H₂S signal enhances the plasticity of the cell wall by regulating the deposition of cellulose fibrils and by decreasing the pectin content. The resulting increases in cellulose and hemicellulose contents lead to cell wall expansion and cell elongation.

中文翻译：

---

硫化氢通过增加苜蓿中的纤维素含量和改变纤维素原纤维的排列来促进下胚轴伸长。

摘要

已知硫化氢（H ₂ S）在植物生长中具有积极的生理功能，但有关其对细胞壁的影响的数据有限。在这里，我们展示了一种新的机制，通过该机制，H ₂ S调节苜蓿（紫花苜蓿）中细胞壁纤维素的生物合成和沉积）。已发现用NaHS处理可增加下胚轴中表皮细胞的长度，转录组分析表明它可导致许多细胞壁相关基因的差异表达。这些差异表达的基因与纤维素和半纤维素的生物合成以及果胶的降解直接相关。细胞壁组成分析表明，NaHS处理可增加纤维素和半纤维素的含量，但降低果胶的含量。原子力显微镜显示，用NaHS处理可降低纤维素原纤维的直径，改变原纤维束的排列，并增加束之间的间距。纤维素合酶复合物（CSC）的动力学与纤维素合成密切相关，NaHS增加了颗粒的迁移率。总体而言，我们的结果表明₂ S信号通过调节纤维素原纤维的沉积并降低果胶含量来增强细胞壁的可塑性。纤维素和半纤维素含量的增加导致细胞壁膨胀和细胞伸长。