Glycoside hydrolase family1 β-glucosidases play a variety of roles in plants, but their in planta functions are largely unknown in rice (Oryza sativa). In this study, the biological function of Os12BGlu38, a rice β-glucosidase, expressed in bicellular to mature pollen, was examined. Genotype analysis of progeny of the self-fertilized heterozygous Os12BGlu38 T-DNA mutant, os12bglu38-1, found no homozygotes and a 1:1 ratio of wild type to heterozygotes. Reciprocal cross analysis demonstrated that Os12BGlu38 deficiency cannot be inherited through the male gamete. In cytological analysis, the mature mutant pollen appeared shrunken and empty. Histochemical staining and TEM showed that mutant pollen lacked intine cell wall, which was rescued by introduction of wild-type Os12BGlu38 genomic DNA. Metabolite profiling analysis revealed that cutin monomers and waxes, the components of the pollen exine layer, were increased in anthers carrying pollen of os12bglu38-1 compared with wild type and complemented lines. Os12BGlu38 fused with green fluorescent protein was localized to the plasma membrane in rice and tobacco. Recombinant Os12BGlu38 exhibited β-glucosidase activity on the universal substrate p-nitrophenyl β-d-glucoside and some oligosaccharides and glycosides. These findings provide evidence that function of a plasma membrane-associated β-glucosidase is necessary for proper intine development.

中文翻译：

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水稻 β-葡萄糖苷酶 Os12BGlu38 是细胞壁合成和花粉育性所必需的

糖苷水解酶家族 1 β-葡萄糖苷酶在植物中发挥多种作用，但它们在植物中的功能在水稻 (Oryza sativa) 中很大程度上是未知的。在本研究中，检测了在成熟花粉双细胞中表达的水稻 β-葡萄糖苷酶 Os12BGlu38 的生物学功能。对自交杂合Os12BGlu38 T-DNA 突变体os12bglu38-1 的后代进行基因型分析，未发现纯合子，野生型与杂合子的比例为1:1。相互交叉分析表明，Os12BGlu38 缺陷不能通过雄性配子遗传。在细胞学分析中，成熟的突变花粉出现萎缩和空洞。组织化学染色和 TEM 显示突变花粉缺乏内膜细胞壁，通过引入野生型 Os12BGlu38 基因组 DNA 得以挽救。代谢物分析表明，与野生型和互补品系相比，携带 os12bglu38-1 花粉的花药中的角质单体和蜡（花粉外壁层的成分）增加了。与绿色荧光蛋白融合的Os12BGlu38定位于水稻和烟草的质膜。重组Os12BGlu38对通用底物对硝基苯基β-d-葡萄糖苷和一些寡糖和糖苷表现出β-葡萄糖苷酶活性。这些发现提供了证据，证明质膜相关 β-葡萄糖苷酶的功能对于正常的内脏发育是必需的。与绿色荧光蛋白融合的Os12BGlu38定位于水稻和烟草的质膜。重组Os12BGlu38对通用底物对硝基苯基β-d-葡萄糖苷和一些寡糖和糖苷表现出β-葡萄糖苷酶活性。这些发现提供了证据，证明质膜相关 β-葡萄糖苷酶的功能对于正常的内脏发育是必需的。与绿色荧光蛋白融合的Os12BGlu38定位于水稻和烟草的质膜。重组Os12BGlu38对通用底物对硝基苯基β-d-葡萄糖苷和一些寡糖和糖苷表现出β-葡萄糖苷酶活性。这些发现提供了证据，证明质膜相关 β-葡萄糖苷酶的功能对于正常的内脏发育是必需的。