Liu Ze, Lin Sen, Shi Jianxin, Yu Jing, Zhu Lu, Yang Xiujuan, Zhang Dabing, Liang Wanqi
Joint International Research Laboratory of Metabolic & Developmental Sciences, State Key Laboratory of Hybrid Rice, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia, 5064, Australia.
Plant J. 2017 Jul;91(2):263-277. doi: 10.1111/tpj.13561. Epub 2017 Jun 1.
Angiosperm male reproductive organs (anthers and pollen grains) have complex and interesting morphological features, but mechanisms that underlie their patterning are poorly understood. Here we report the isolation and characterization of a male sterile mutant of No Pollen 1 (NP1) in rice (Oryza sativa). The np1-4 mutant exhibited smaller anthers with a smooth cuticle surface, abnormal Ubisch bodies, and aborted pollen grains covered with irregular exine. Wild-type exine has two continuous layers; but np1-4 exine showed a discontinuous structure with large granules of varying size. Chemical analysis revealed reduction in most of the cutin monomers in np1-4 anthers, and less cuticular wax. Map-based cloning suggested that NP1 encodes a putative glucose-methanol-choline oxidoreductase; and expression analyses found NP1 preferentially expressed in the tapetal layer from stage 8 to stage 10 of anther development. Additionally, the expression of several genes involved in biosynthesis and in the transport of lipid monomers of sporopollenin and cutin was decreased in np1-4 mutant anthers. Taken together, these observations suggest that NP1 is required for anther cuticle formation, and for patterning of Ubisch bodies and the exine. We propose that products of NP1 are likely important metabolites in the development of Ubisch bodies and pollen exine, necessary for polymerization, assembly, or both.
被子植物的雄性生殖器官（花药和花粉粒）具有复杂而有趣的形态特征，但其形态形成的机制却知之甚少。在此，我们报道了水稻（Oryza sativa）中一个无花粉1（NP1）雄性不育突变体的分离与鉴定。np1 - 4突变体的花药较小，角质层表面光滑，乌氏体异常，花粉粒败育，外壁不规则。野生型外壁有两层连续结构；但np1 - 4外壁呈现出不连续结构，有大小不一的大颗粒。化学分析表明，np1 - 4花药中大多数角质单体减少，角质层蜡质也减少。图位克隆表明，NP1编码一种假定的葡萄糖 - 甲醇 - 胆碱氧化还原酶；表达分析发现，NP1在花药发育的第8阶段到第10阶段在绒毡层中优先表达。此外，np1 - 4突变体花药中几个参与孢粉素和角质脂质单体生物合成及转运的基因表达下降。综上所述，这些观察结果表明，NP1是花药角质层形成、乌氏体和外壁形态形成所必需的。我们推测，NP1的产物可能是乌氏体和花粉外壁发育过程中的重要代谢产物，对于聚合、组装或两者都必不可少。
