Pollen-specific gene SKU5-SIMILAR 13 enhances growth of pollen tubes in the transmitting tract in Arabidopsis

SKU5-SIMILAR 13enhances pollen tube growth in the transmitting tract by mediating the biosynthesis of jasmonic acid and modifying the pollen tube cell walls in Arabidopsis thaliana. 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.

Automated summary

The gene SKU5-SIMILAR 13 plays a critical role in pollen tube growth in the transmitting tract of Arabidopsis thaliana by mediating the biosynthesis of jasmonic acid and modifying cell wall components. Mutations in the SKS13 gene lead to altered cell wall components and retarded growth of pollen tubes, affecting male fertility during the pollen transfer process. Our results suggest that SKS13 is essential for pollen tube growth in the transmitting tract through the regulation of jasmonic acid biosynthesis.