Background

Rice blast caused by Magnaporthe oryzae is one of the most destructive diseases of rice. An increasing number of microRNAs (miRNAs) have been reported to fine-tune rice immunity against M. oryzae and coordinate with growth and development.

Results

Here, we showed that rice microRNA159a (Osa-miR159a) played a positive role in rice resistance to M. oryzae. The expression of Osa-miR159a was suppressed in a susceptible accession at 12, 24, and 48 h post-inoculation (hpi); it was upregulated in a resistant accession of M. oryzae at 24 hpi. The transgenic rice lines overexpressing Osa-miR159a were highly resistant to M. oryzae. In contrast, the transgenic lines expressing a short tandem target mimic (STTM) to block Osa-miR159a showed enhanced susceptibility. Knockout mutations of the target genes of Osa-miR159a, including OsGAMYB, OsGAMYBL, and OsZF, led to resistance to M. oryzae. Alteration of the expression of Osa-miR159a impacted yield traits including pollen and grain development.

Conclusions

Our results indicated that Osa-miR159a positively regulated rice immunity against M. oryzae by downregulating its target genes. Proper expression of Osa-miR159a was critical for coordinating rice blast resistance with grain development.

中文翻译：

---

Osa-miR159a 在水稻抗稻瘟病免疫和发育中的微调作用

 背景

由稻瘟病菌引起的稻瘟病是水稻最具破坏性的病害之一。据报道，越来越多的 microRNA (miRNA) 可以微调水稻对米霉的免疫力并协调生长和发育。

 结果

在这里，我们证明水稻 microRNA159a ( Osa-miR159a ) 在水稻对米霉的抗性中发挥着积极作用。接种后 12、24 和 48 小时 (hpi) 的易感种质中Osa-miR159a的表达受到抑制；它在米霉抗性种质中在 24 hpi 时上调。过表达Osa-miR159a的转基因水稻品系对米霉具有高度抗性。相比之下，表达短串联靶模拟物（STTM）以阻断Osa-miR159a 的转基因系表现出增强的敏感性。 Osa-miR159a靶基因（包括OsGAMYB 、 OsGAMYBL和OsZF ）的敲除突变导致对米霉的抗性。 Osa-miR159a表达的改变影响产量性状，包括花粉和籽粒发育。

 结论

我们的结果表明， Osa-miR159a通过下调其靶基因来正向调节水稻对米霉的免疫力。 Osa-miR159a的正确表达对于协调稻瘟病抗性与籽粒发育至关重要。