Pollen-Expressed Leucine-Rich Repeat Extensins Are Essential for Pollen Germination and Growth
Pollen-Expressed Leucine-Rich Repeat Extensins Are Essential for Pollen Germination and Growth
复制标题
花粉表达的富含亮氨酸的重复延伸蛋白对于花粉萌发和生长至关重要
DOI：
10.1104/pp.17.01241
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发表时间：
2018-03-01
期刊：
影响因子：
7.4
通讯作者：
Guo, Yi
中科院分区：
文献类型：
--
作者：
Wang, Xiaoxiao;Wang, Kaiyue;Guo, Yi
在花粉管生长过程中，管壁提供抵抗膨压的机械强度以保护两个精细胞。细胞壁蛋白在这一过程中可能发挥重要作用。富含亮氨酸重复序列延伸蛋白（LRX）的花粉管细胞壁蛋白具有一个富含亮氨酸重复序列结构域和一个延伸蛋白结构域。在这项研究中，四个花粉表达的LRX，LRX 8，LRX 9，LRX 10，和LRX 11（LRX 8 -11），在拟南芥（拟南芥）的功能进行了表征。LRX 8 -11在成熟花粉粒和花粉管中的表达模式一致。在4个单突变体，6个双突变体，4个三重突变体，和一个四重突变体的表型分析，三重和四重突变体植物表现出显着减少结实率和降低雄性传递效率伴随着受损的花粉萌发和花粉管生长。发现GFP融合的LRX 8、LRX 10和LRX 11定位于花粉管细胞壁。花粉管细胞壁多糖的免疫组织化学分析表明，在LRX 9 LRX 10 LRX 11和LRX 8 LRX 9 LRX 11突变体的花粉管近顶壁中的鼠李糖半乳糖醛酸聚糖I的量增加，并且与野生型植物相比，在LRX 8 LRX 9 LRX 11中岩藻糖基化木葡聚糖的含量减少。此外，在lrx 8 lrx 9 lrx 11突变体中，花粉管顶端壁中的胼胝质含量增加。综上所述，我们认为LRX 8 -11在维持花粉管细胞壁完整性方面具有协同作用，因此，它们在花粉萌发和花粉管生长中起着关键作用。
During pollen tube growth, the walls of the tube provide the mechanical strength resisting turgor pressure to protect two sperm cells. Cell wall proteins may play an important role in this process. Pollen tube cell wall proteins known as leucine-rich repeat extensins (LRXs) harbor a leucine-rich repeat domain and an extensin domain. In this study, the functions of four pollen-expressed LRXs, LRX8, LRX9, LRX10, and LRX11 (LRX8-11), were characterized in Arabidopsis (Arabidopsis thaliana). LRX8-11 displayed a consistent expression pattern in mature pollen grains and pollen tubes. In a phenotypic analysis of four single mutants, six double mutants, four triple mutants, and a quadruple mutant, the triple and quadruple mutant plants displayed markedly reduced seed set and decreased male transmission efficiency accompanied by compromised pollen germination and pollen tube growth. GFP-fused LRX8, LRX10, and LRX11 were found to be localized to pollen tube cell walls. An immunohistochemical analysis of pollen tube cell wall polysaccharides showed an increase in the amount of rhamnogalacturonan I in the subapical walls of pollen tubes of the lrx9 lrx10 lrx11 and lrx8 lrx9 lrx11 mutants and a decrease in the content of fucosylated xyloglucans in lrx8 lrx9 lrx11 compared with wild-type plants. Moreover, the callose content in the apical walls of pollen tubes increased in the lrx8 lrx9 lrx11 mutant. In conclusion, we propose that LRX8-11 function synergistically to maintain pollen tube cell wall integrity; thus, they play critical roles in pollen germination and pollen tube growth.