甘薯近缘野生种三浅裂野牵牛KNOX基因家族鉴定及其在块根发育中的表达分析OA北大核心CSTPCD

To reveal the role of KNOX(ItrKNOX)gene family in the storage root(SR)development of Ipomoea trifida,a close relative of sweetpotato,this study identified the members of ItrKNOX family in I.trifida cv.Y22 at the genome level and analyzed their expressions at different SR development stages by transcriptome sequencing.A total of 12 ItrKNOX genes(ItrKNOXs)distributed on 10 chromosomes were identified.Phylogenetic analysis showed that these ItrKNOXs could be clustered into three categories:Class Ⅰ,Class Ⅱand Class M.The types and numbers of KNOX genes were conserved in the genomes of four diploid species from the Ipomoea genus,including I.trifida,I.triloba,I.nil and I.purpurea.Among them,I.trifida and I.triloba were closely related.Several cis-acting elements within the promoter regions of ItrKNOXs were found to be associated with plant development,hormones,light and stress.Transcriptome analysis showed that the expression patterns of ItrKNOXs were diversified during the SR development of Y22.The Class M gene ItrKNOX12 was almost unexpressed,while ItrKNOX02,ItrKNOX03,ItrKNOX09 and ItrKNOX10 were highly expressed during root development.The significant up-regulation of ItrKNOX01,ItrKNOX02,ItrKNOX03,ItrKNOX05,ItrKNOX09 and ItrKNOX11,as well as the significant down-regulation of ItrKNOX08,were observed from adventitious root(AR)to SR stages.Notably,the expression of ItrKNOX06 was significantly up-regulated only after the SR exceeded 2 mm in diameter.Meanwhile,the expression levels of ItrKNOX07 in AR and mature SR were significantly lower than those in developing SRs.This study provides a reference for further research on the function and regulatory mechanism of KNOX genes in sweetpotato and its related wild species I.trifida.