Key message

In this manuscript, we show that Oryza sativa indica Argonaute protein AGO18 is required for male gametophyte development likely to through a small RNA-mediated mechanism.

Abstract

Monocots have evolved unique gene silencing pathways due to the presence of unique members of Dicer-like and Argonaute (AGO) family members. Among the monocot AGO homologs, AGO18 occupies a unique position. Previous reports have implicated this protein in viral resistance as well as in gametogenesis, likely through its competition with AGO1 clade members for micro(mi)RNAs and other small (s)RNAs. Although expression of rice AGO18 in specific stages of male gametogenesis has been documented, its major functions in plant development remain poorly understood. Here, we show that Oryza sativa indica AGO18 is involved in male gametophyte development. Knockdown (KD) of AGO18 in transgenic rice lines resulted in stunted plants that are male sterile, whereas their carpels were functional. Transcriptome analysis revealed downregulation of several pollen development-associated genes in KD lines. sRNA sequencing in vegetative and reproductive tissues of KD lines indicated reduction of miRNAs and phased secondary sRNAs implicated in male gametophyte development. Our results indicate a distinct role for rice AGO18 in male fertility.

中文翻译：

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水稻Argonaute 18的功能丧失会导致雄性不育并导致分阶段的小RNA减少。

关键信息

在此手稿中，我们表明，可能通过小RNA介导的机制，雄配子体发育需要水稻y稻Argonaute蛋白AGO18。

抽象

由于存在Dicer样和Argonaute（AGO）家族成员的独特成员，单子叶植物已进化出独特的基因沉默途径。在单子叶植物AGO同源物中，AGO18占据独特的位置。先前的报道可能通过与AGO1进化枝成员竞争micro（mi）RNA和其他小（s）RNA的方式使这种蛋白质与病毒抗性以及配子发生有关。尽管已经报道了水稻AGO18在雄性配子发生的特定阶段的表达，但其在植物发育中的主要功能仍知之甚少。在这里，我们显示印度稻AGO18参与雄配子体发育。转基因水稻品系中的AGO18敲低（KD）导致了雄性不育的发育不良植物，而它们的心皮却起作用。转录组分析揭示了KD系中几个与花粉发育相关的基因的下调。在KD系的营养和生殖组织中进行sRNA测序表明，与雄配子体发育有关的miRNA和分阶段的次级sRNA减少。我们的结果表明水稻AGO18在雄性育性中具有独特的作用。