Abstract：
The successful germination of pollen is essential for double fertilization in flowering plants. Mechanosensitive channels of small conductance (MscS-like, MSL) inhibit pollen germination and maintains cellular integrity of pollen during this process. Therefore, it is vital to carefully regulate the expression of MSL to promote successful pollen germination. Despite its importance, the molecular mechanisms governing MSL expression in plants remain poorly understood. Here, we had identified 15 MSL genes in the pear, among which PbrMSL5 was expressed in pollen development. Subcellular localization experiments revealed that PbrMSL5 was located in both plasma membrane and cytoplasm. Functional investigations, including complementation experiments using the atmsl8 mutant background, demonstrated the involvement of PbrMSL5 in preserving pollen cell integrity and inhibiting germination. Antisense oligonucleotide experiments further confirmed that PbrMSL5 suppressed pear pollen germination by reducing osmotic pressure and Cl- content. Yeast one-hybrid, electrophoretic mobility shift assays, and dual luciferase reporter assay elucidated that PbrMYC8 interacts directly with the N-box element, leading to the suppression of PbrMSL5 expression and promoted pollen germination. These results represented a significant advancement in unraveling the molecular mechanisms controlling plant MSL expression. This study showed valuable contribution to advancing our comprehension of the mechanism underlying pollen germination.
摘要：
花粉的成功发芽对于开花植物的双重受精至关重要。小电导的机械敏感通道(类MscS，MSL）在此过程中抑制花粉萌发并保持花粉的细胞完整性。因此,仔细调节MSL的表达对促进花粉成功萌发至关重要。尽管它很重要,控制植物中MSL表达的分子机制仍然知之甚少。这里,我们在梨中鉴定了15个MSL基因，其中PbrMSL5在花粉发育中表达。亚细胞定位实验表明，PbrMSL5位于质膜和细胞质中。功能调查，包括使用atmsl8突变体背景的互补实验，证明了PbrMSL5参与保持花粉细胞完整性和抑制萌发。反义寡核苷酸实验进一步证实，PbrMSL5通过降低渗透压和Cl-含量来抑制梨花粉萌发。酵母单杂种，电泳迁移率变化测定，双荧光素酶报告基因测定阐明了PbrMYC8与N盒元件直接相互作用，导致抑制PbrMSL5的表达并促进花粉萌发。这些结果代表了在揭示控制植物MSL表达的分子机制方面的重大进展。这项研究为促进我们对花粉萌发机制的理解做出了有价值的贡献。
