The miR156 and plant specific transcription factor SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) are known for their function regulating plant growth and development. In this study, we identified 20 GmSPLs which are targeted by gma-miR156b via plant small RNA target and degradome analysis. And we found high transcript levels of gma-miR156b and its targeted GmSPLs in the flower of soybean cytoplasmic male sterility (CMS) line and its maintainer. The gma-miR156b direct cleavage of GmSPL2b and GmSPL9b, and have opposite expression levels during early flower buds development. We observed a high expression level of GUS protein in the anthers of the line with pgma-MIR156b::GUS reporter. Over-expression of the gma-miR156b precursor in Arabidopsis inhibited floral organ development, including reduced anther size and the amount of pollen grains per anther etc. Like miR156-targeted SPL genes, non-targeted GmSPL8s were also down-regulated in early flower bud development of soybean CMS line compared with its maintainer line, which might act in concert with miR156-targeted SPL genes to participate in the floral organ development. Quantitative real time PCR (qRT-PCR) suggested that miR156/SPL modulates floral organ development by regulating the expression of LATERAL ORGAN BOUNDARIES DOMAIN22 (LBD22), LBD36, AGAMOUS-LIKE30 (AGL30) and AGL104. Our findings will facilitate understanding of the biological functions of miR156/SPL in floral organ development of soybean CMS.

中文翻译：

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大豆CMS系列的miR156b调节花器官发育

miR156和植物特异性转录因子SQUAMOSA PROPERTER BINDING蛋白类似物（SPL）以调节植物生长和发育的功能而闻名。在这项研究中，我们通过植物小RNA靶标和降解组分析确定了gma-miR156b靶向的20 GmSPL。我们在大豆细胞质雄性不育（CMS）品系及其维持物中发现了高水平的gma-miR156b及其靶向的GmSPL。该GMA-miR156b的直接裂解GmSPL2b和GmSPL9b，并且在早期花芽发育过程中具有相反的表达水平。我们用pgma-MIR156b :: GUS报告基因观察到该系花药中GUS蛋白的高表达水平。gma-miR156b前体在拟南芥中的过表达抑制花器官发育，包括减少花药大小和每株花药的花粉粒数量等。像miR156靶向的SPL基因一样，非靶向的GmSPL8也在早花中下调大豆CMS系与其保持系的芽发育可能与miR156靶向的SPL基因协同作用，参与花器官的发育。实时定量PCR（qRT-PCR）表明miR156 /SPL通过调节横向有机器官DOMAIN22（LBD22），LBD36，AGAMOUS-LIKE30（AGL30）和AGL104的表达来调节花器官的发育。我们的发现将有助于理解miR156 / SPL在大豆CMS花器官发育中的生物学功能。