State Key Laboratory of Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China.
AgResearch Limited, Grassland Research Centre, Palmerston North 4442, New Zealand.
Sci Rep. 2018 Apr 19;8(1):6287. doi: 10.1038/s41598-018-24477-x.
Cleistogenes songorica, a grass species that exhibits two spatially different type of inflorescence, chastogamy (CH), flowers localized at the top, and cleistogamy (CL) flowers embedded in leaf sheath. This study aimed at dissecting reasons underlying these distinct floral development patterns at morphological and microRNA level. Phenotyping for CH and CL was conducted and four small RNA libraries were constructed from the CH and CL flowers for high-throughput sequencing to identify the differentiated miRNAs. As results, spikelet, stigma, anther, lemma and lodicule length of CH flowers were found larger than that of CL, and so was seed setting. Also, 17 flower-related differential expression miRNAs were identified which were associated with floral organ development and morphogenesis, and the flower development. Further results showed that miR159a.1-CL3996.Contig2 pair was related to anther development, miR156a-5p-CL1954.Contig2 was linked to response to high light intensity, miR408-3p/miR408d-Unigene429 was related to pollination and Unigene429 positively regulated flower development. To our knowledge, this is the first study on differential miRNA accumulation between CH and CL flowers and our study serves as a foundation to the future elucidation of regulatory mechanisms of miRNAs in the divergent development of CL and CH flowers in a single plant.
糙苏，一种具有两种不同空间位置花序类型的草本植物，分别是穗状的雌雄同熟花（CH）和生于叶鞘内的闭花受精花（CL）。本研究旨在从形态和 microRNA 水平上解析导致这些不同花发育模式的原因。对 CH 和 CL 的表型进行了分析，并从 CH 和 CL 花中构建了四个小 RNA 文库，进行高通量测序以鉴定差异表达的 miRNAs。结果表明，CH 花的小穗、柱头、花药、外稃和内稃长度大于 CL 花，结实率也更高。还鉴定出了 17 个与花器官发育和形态发生以及花发育相关的差异表达 miRNA，进一步的结果显示，miR159a.1-CL3996.Contig2 对与花药发育有关，miR156a-5p-CL1954.Contig2 与高光强度响应有关，miR408-3p/miR408d-Unigene429 与授粉有关，而 Unigene429 正向调控花的发育。据我们所知，这是首次对 CH 和 CL 花之间差异 miRNA 积累的研究，我们的研究为未来阐明单株植物中 CL 和 CH 花不同发育的 miRNA 调控机制奠定了基础。
