Pollen tube growth and penetration in female tissues are essential for the transfer of sperm to the embryo sac during plant pollination. Despite its importance during pollination, little is known about the mechanisms that mediate pollen tube growth in female tissues. In this study, we identified an Arabidopsis thaliana pollen/pollen tube-specific gene, SKU5-SIMILAR 13 (SKS13), which was critical for the growth of pollen tubes in the transmitting tract. The SKS13 protein was distributed throughout the cytoplasm and pollen tube walls at the apical region. In comparison with wild-type pollen tubes, those of the sks13 mutants burst more frequently when grown in vitro. Additionally, the growth of sks13 pollen tubes was retarded in the transmitting tract, thereby resulting in decreased male fertility. The accumulation of pectin and cellulose in the cell wall of sks13 pollen tubes was altered, and the content of jasmonic acid (JA) in sks13 pollen was reduced. The pollen tubes treated with an inhibitor of JA biosynthesis grew much more slowly and had an altered distribution of pectin, which is similar to the pollen tube phenotypes of the SKS13 mutation. Our results suggest that SKS13 is essential for pollen tube growth in the transmitting tract by mediating the biosynthesis of JA that modifies the components of pollen tube cell walls.

中文翻译：

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花粉特异性基因 SKU5-SIMILAR 13 增强拟南芥传播道中花粉管的生长

花粉管在雌性组织中的生长和渗透对于植物授粉过程中精子向胚囊的转移至关重要。尽管它在授粉过程中很重要，但对介导雌性组织中花粉管生长的机制知之甚少。在这项研究中，我们鉴定了拟南芥花粉/花粉管特异性基因 SKU5-SIMILAR 13 (SKS13)，该基因对花粉管在传播道中的生长至关重要。SKS13 蛋白分布于整个细胞质和顶端区域的花粉管壁。与野生型花粉管相比，sks13 突变体的花粉管在体外生长时更频繁地爆发。此外，sks13 花粉管在传播道中的生长迟缓，从而导致雄性生育力下降。sks13花粉管细胞壁中果胶和纤维素的积累发生改变，sks13花粉中茉莉酸(JA)的含量降低。用 JA 生物合成抑制剂处理的花粉管生长更慢，果胶分布发生变化，这与 SKS13 突变的花粉管表型相似。我们的研究结果表明，SKS13 通过介导 JA 的生物合成来改变花粉管细胞壁的成分，对传递道中的花粉管生长至关重要。