miR3954 is a trigger of phasiRNAs that affects flowering time in citrus

Corresponding author: Qiang Xu (徐强)

In plant, a few 22-nt miRNAs direct cleavages of their targets and trigger the biogenesis (生物合成) of phased small interfering RNAs (phasiRNAs; 阶段性小干扰RNA) in plant. In this study, we characterized a miRNA triggering phasiRNAs generation, miR3954, and explored its downstream target genes and potential function. Our results demonstrated that miR3954 showed specific expression in the flowers of citrus species, and it targeted a NAC transcription factor (Cs7 g22460) and two non-coding RNA transcripts (lncRNAs, Cs1 g09600 and Cs1 g09635). The production of phasiRNAs was detected from transcripts targeted by miR3954, and was further verified in both sequencing data and transient expression experiments. PhasiRNAs derived from the two lncRNAs targeted not only miR3954-targeted NAC gene but also additional NAC homologous genes. No homologous genes of these two lncRNAs were found in plants other than citrus species, implying that this miR3954-lncRNAs-phasiRNAs-NAC pathway is likely citrus-specific. Transgenic analysis indicated that the miR3954-overexpressing lines showed decreased transcripts of lncRNA, elevated (升高的) abundance of phasiRNAs and reduced expression of NAC genes. Interestingly, the overexpression of miR3954 leads to early flowering in citrus plants. In summary, our results illustrated a model of the regulatory network of miR3954-lncRNA-phasiRNAs-NAC, which may be functionally involved in flowering in citrus.

通讯：徐强 (http://linx.hzau.edu.cn/szxx/zzjs/gsx/jiaoshou/201403/t20140305_37532.htm)

个人简介：1998-2002年，华中农业大学，园艺学士；2002-2007年，华中农业大学，园艺博士；2009-2010年，美国康奈尔大学合作研究。

研究方向：柑橘果实品质调控机理研究；耐黄龙病基因发掘与耐病机理解析；基于基因组学的分子工具开发及辅助育种。

（p.s. 徐强老师2013以第一作者身份在Nature Genetics上发表甜橙基因组，2017年又以第一通讯身份在Nature Genetics上发表柑橘基因组）

doi: 10.1111/tpj.13650

（P.S. 欢迎访问个人博客：https://plantfrontiers.wordpress.com）