Pollen grains are covered by exine that protects the pollen from stress and facilitates pollination. Here we isolated a male sterile mutant s13283 in rice exhibiting aborted pollen with abnormal exine and defective aperture. The mutant gene encodes a novel plasma membrane‐localized legume‐lectin receptor kinase that we named OsLecRK‐S.7. OsLecRK‐S.7 was expressed at different levels in all tested tissues and throughout anther development. In vitro kinase assay showed OsLecRK‐S.7 capable of autophosporylation. Mutation in s13283 (E560K) and mutation of the conserved ATP binding site (K418E) both knocked out the kinase activity. Mass spectrometry showed Thr₃₇₆, Ser₃₇₈, Thr₃₈₆, Thr₄₀₃, and Thr₆₅₇ to be the autophosphorylation sites. Mutation of individual autophosphorylation site affected the in vitro kinase activity to different degrees, but did not abolish the gene function in fertility complementation. oslecrk‐s.7 mutant plant overexpressing OsLecRK‐S.7 recovered male fertility but showed severe growth retardation with reduced number of tillers, and these phenotypes were abolished by E560K or K418E mutation. The results indicated that OsLecRK‐S.7 was a key regulator of pollen development.

中文翻译：

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凝集素受体激酶OsLecRK-S.7是花粉发育和雄性育性所必需的。

花粉被谷物覆盖着，可以保护花粉免受压力并促进授粉。在这里，我们在水稻中分离出一个雄性不育突变体s13283，该突变体表现出流产的花粉，外在异常和孔径缺陷。该突变基因编码一种新型的质膜定位的豆科植物凝集素受体激酶，我们将其命名为OsLecRK-S.7。OsLecRK-S.7在所有测试组织和整个花药发育过程中均以不同水平表达。体外激酶测定显示OsLecRK-S.7具有自磷酸化能力。突变s13283（E560K）与保守的ATP结合位点（K418E）都被淘汰的激酶活性的突变。质谱显示Thr ₃₇₆，Ser ₃₇₈，Thr₃₈₆，Thr ₄₀₃和Thr ₆₅₇是自磷酸化位点。单个自身磷酸化位点的突变在不同程度上影响了体外激酶的活性，但并未消除生育力互补中的基因功能。oslecrk-S.7突变植物过量表达OsLecRK-S.7回收男性的生育能力，但显示出严重的生长迟缓具有降低分蘖数，并且这些表型是由E560K或K418E突变废除。结果表明，OsLecRK-S.7是花粉发育的关键调节剂。