温度调控花粉壁发育的机理

植物花粉外壁是植物独有的结构，不仅在保护花粉正常发育，对植物育性起关键作用，也是物种分类的重要依据之一。来自于绒毡层的孢粉素前体在减数分裂后产生的四分体中积累，随着四分体胼胝质壁的降解，孢粉素持续积累形成具有植物物种特异性的花粉壁模式结构。在模式植物拟南芥中, 已报道十多个参与孢粉素合成、胼胝质壁以及与初生外壁形成相关的基因。我们的前期研究发现这些基因的部分雄性不育突变体在低温下能够形成有功能的花粉。本项目将在分子和遗传水平上系统地研究：1）孢粉素前体如何在小孢子表面沉积形成独特的模式；2）筛选与花粉壁模式以及孢粉素合成相关的温敏突变体，研究其育性与温度的关系；3）通过回复子基因功能研究，从基因和细胞水平上理解温敏育性转换的分子基础，揭示调控这些过程的共性规律。本项目研究成果有助于花粉壁模式形成这一经典植物学问题的系统解析。

The unique structure of pollen wall not only protects the pollen from various environmental stresses, but also provides evidences for the dynamics of plant phylogeny. After meiosis, the sporopollenin precursors derived from tapetum initially accumulates in tetrads. Late, following the callose wall degradation, sporopollenin gradually forms into a species-specific pollen wall pattern. In model plant Arabidopsis, several genes involved in sporopollenin synthesis, callose wall and primexine formation have been reported. We found that the fertility of some male sterile lines of these genes can be rescued under low temperature. In this project, we will systematically study how these genes act in concert to regulate the pollen wall pattern formation and how low temperature overcomes pollen wall pattern defective for pollen function. The project will investigate: 1) how the sporopollenin precursors deposit onto the microspore surface to form the unique pattern; 2) screening thermo-sensitive mutants related to pollen wall pattern and sporopollen synthesis to study the relationship between fertility and temperature; 3) understanding the molecular basis of thermo-sensitive fertility conversion by studying of supressor genes, revealing the general mechanism of environment regulation . The results of this project should provide insights into the formation of pollen wall pattern on molecular and genetic level.