Guan Jian, Li Jinyan, Yao Qingyu, Liu Zhiyong, Feng Hui, Zhang Yun
College of Horticulture, Shenyang Agricultural University, Shenyang, China.
Front Plant Sci. 2022 Dec 19;13:1083528. doi: 10.3389/fpls.2022.1083528. eCollection 2022.
Branching is an important agronomic trait determining plant architecture and yield; however, the molecular mechanisms underlying branching in the stalk vegetable, flowering Chinese cabbage, remain unclear. The present study identified two tandem genes responsible for primary rosette branching in flowering Chinese cabbage by GradedPool-Seq (GPS) combined with Kompetitive Allele Specific PCR (KASP) genotyping. A 900 kb candidate region was mapped in the 28.0-28.9 Mb interval of chromosome A07 through whole-genome sequencing of three graded-pool samples from the F population derived by crossing the branching and non-branching lines. KASP genotyping narrowed the candidate region to 24.6 kb. Two tandem genes, and , homologous to encoding GA2ox1 oxidase, were identified as the candidate genes. The sequence was identical between the branching and non-branching lines, but had a synonymous single nucleotide polymorphic (SNP) mutation in the first exon (290 bp, A to G). In addition, an ERE -regulatory element was absent in the promoter of , and an MYB -regulatory element in the promoter of in the branching line. Gibberellic acid (GA) treatment decreased the primary rosette branch number in the branching line, indicating the significant role of GA in regulating branching in flowering Chinese cabbage. These results provide valuable information for revealing the regulatory mechanisms of branching and contributing to the breeding programs of developing high-yielding species in flowering Chinese cabbage.
分枝是决定植物株型和产量的重要农艺性状；然而，茎用蔬菜菜薹分枝的分子机制仍不清楚。本研究通过梯度池测序（GPS）结合竞争性等位基因特异性PCR（KASP）基因分型，鉴定了两个负责菜薹一级分枝的串联基因。通过对分枝和不分枝品系杂交得到的F群体的三个梯度池样本进行全基因组测序，在A07染色体的28.0 - 28.9 Mb区间定位了一个900 kb的候选区域。KASP基因分型将候选区域缩小到24.6 kb。两个与编码GA2ox1氧化酶的基因同源的串联基因被鉴定为候选基因。分枝和不分枝品系之间的 序列相同，但 在第一个外显子（290 bp，A突变为G）中有一个同义单核苷酸多态性（SNP）突变。此外，分枝品系中 的启动子中缺少一个ERE调控元件， 启动子中缺少一个MYB调控元件。赤霉素（GA）处理减少了分枝品系的一级菜薹分枝数，表明GA在调控菜薹分枝中起重要作用。这些结果为揭示分枝调控机制和促进菜薹高产品种育种计划提供了有价值的信息。
