Sorghum SbGhd7 is a major regulator of floral transition and directly represses genes crucial for flowering activation

Sorghum is multipurpose crop worldwide serving as food, feed, and feedstock for biofuels, whose floral transition and vegetative growth heavily depend on photoperiod. Although multiple sorghum maturity loci (Ma1-Ma6) have been associated with photoperiod sensitivity in previous QTL studies, the underlying molecular mechanisms remain poorly understood. By functional characterizing sorghum SbGhd7 (Ma6) and integrating RNA-seq analysis of Ghd7 overexpression sorghum, ChIP-seq analysis of SbGhd7 binding sites in protoplasts and molecular studies, we discovered that SbEhd1 and SbFT10 are the direct targets of SbGhd7. SbGhd7 is a transcriptional repressor and inhibits florigen-induced floral transition by repressing SbEhd1 and SbFT10 expression. Overall design: Comparative gene expression profiling analysis of RNA-seq data for leaf tissues from 4-week-old empty vector control and SbGhd7 overexpression (SbGhd7 OE) sorghum plants.

高粱（Sorghum）是全球多用途作物，可作为粮食、饲料及生物燃料原料，其成花转变与营养生长高度依赖光周期。尽管此前的数量性状基因座（quantitative trait locus, QTL）研究已鉴定出多个高粱成熟位点（Ma1-Ma6）与光周期敏感性相关，但其潜在分子机制仍未得到充分阐释。本研究通过对高粱SbGhd7（Ma6）进行功能表征，整合Ghd7过表达高粱的转录组测序（RNA-seq）分析、原生质体中SbGhd7结合位点的染色质免疫共沉淀测序（ChIP-seq）分析及分子生物学实验，发现SbEhd1与SbFT10是SbGhd7的直接靶基因。SbGhd7属于转录抑制因子，可通过抑制SbEhd1与SbFT10的表达，阻碍成花素诱导的成花转变。整体实验设计：对4周龄空载体对照与SbGhd7过表达（SbGhd7 OE）高粱植株的叶片组织进行RNA-seq测序，开展比较基因表达谱分析。