Cotton which produces natural fiber materials for the textile industry is one of the most important crops in the world. Class II KNOX proteins are often considered as transcription factors in regulating plant secondar...Cotton which produces natural fiber materials for the textile industry is one of the most important crops in the world. Class II KNOX proteins are often considered as transcription factors in regulating plant secondary cell wall(SCW) formation. However,the molecular mechanism of the KNOX transcription factor-regulated SCW synthesis in plants(especially in cotton) remains unclear in details so far. In this study, we show a cotton class II KNOX protein(Gh KNL1) as a transcription repressor functioning in fiber development. The Gh KNL1-silenced transgeniccotton produced longer fibers with thicker SCWs,whereas Gh KNL1 dominant repression transgenic lines displayed the opposite fiber phenotype, compared with controls. Further experiments revealed that Gh KNL1 could directly bind to promoters of Gh Ces A4-2/4-4/8-2 and Gh MYB46 for modulating cellulose synthesis during fiber SCW development in cotton. On the other hand, Gh KNL1 could also suppress expressions of Gh EXPA2 D/4 A-1/4 D-1/13 A through binding to their promoters for regulating fiber elongation of cotton. Taken together, these data revealed Gh KNL1 functions in fiber elongation and SCW formation by directly repressing expressions of its target genes related to cell elongation and cellulose synthesis. Thus, our data provide an effective clue for potentially improving fiber quality by genetic manipulation of Gh KNL1 in cotton breeding.展开更多
基金supported by National Natural Science Foundation of China(Grant No.31871667,31471542)the project from the Ministry of Agriculture of China for transgenic research(Grant No.2016ZX08009-003)。
文摘Cotton which produces natural fiber materials for the textile industry is one of the most important crops in the world. Class II KNOX proteins are often considered as transcription factors in regulating plant secondary cell wall(SCW) formation. However,the molecular mechanism of the KNOX transcription factor-regulated SCW synthesis in plants(especially in cotton) remains unclear in details so far. In this study, we show a cotton class II KNOX protein(Gh KNL1) as a transcription repressor functioning in fiber development. The Gh KNL1-silenced transgeniccotton produced longer fibers with thicker SCWs,whereas Gh KNL1 dominant repression transgenic lines displayed the opposite fiber phenotype, compared with controls. Further experiments revealed that Gh KNL1 could directly bind to promoters of Gh Ces A4-2/4-4/8-2 and Gh MYB46 for modulating cellulose synthesis during fiber SCW development in cotton. On the other hand, Gh KNL1 could also suppress expressions of Gh EXPA2 D/4 A-1/4 D-1/13 A through binding to their promoters for regulating fiber elongation of cotton. Taken together, these data revealed Gh KNL1 functions in fiber elongation and SCW formation by directly repressing expressions of its target genes related to cell elongation and cellulose synthesis. Thus, our data provide an effective clue for potentially improving fiber quality by genetic manipulation of Gh KNL1 in cotton breeding.
