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杨树R2R3-MYB基因家族包括194个成员,参与众多生长发育过程。我们前期的研究表明杨树PdMYB90/167是一对同源基因,在拟南芥中能够调控茎秆次生细胞壁的形成、花器官发育和开花时间。本文从功能上鉴定了PdMYB90/167的另一个同源基因PdMYB161,生化和遗传证据表明该基因在杨树茎秆木质部大量表达,编码蛋白定位于细胞核,在拟南芥中过表达导致转基因植株早衰并倒伏,茎秆细胞壁变薄,纤维素、半纤维素和木质素含量降低,对应基因的表达量也发生显著变化。这些结果意味着PdMYB161基因可能参与杨树茎秆次生木质部的形成和植株衰老。结合以前的研究结果,我们认为PdMYB161和PdMYB90/167基因在进化过程中可能产生功能异化,这些结果也为植物同源基因功能进化提供了新证据。
The poplar R2R3-MYB gene family includes 194 members involved in numerous growth and development processes. Our previous studies showed that the poplar PdMYB90 / 167 is a pair of homologous genes that regulate the formation of secondary cell wall, flower organ development and flowering time in Arabidopsis thaliana. In this study, PdMYB90 / 167, another homologous gene of PdMYB90 / 167, was identified. Biochemical and genetic evidence showed that this gene was abundantly expressed in the xylem of poplar stalk. The encoded protein was located in the nucleus and overexpression in Arabidopsis resulted in premature decline in transgenic plants And lodging, the stem cell wall thinning, cellulose, hemicellulose and lignin content decreased, the corresponding gene expression also changed significantly. These results suggest that PdMYB161 may be involved in the formation of secondary xylem and plant senescence of poplar stalk. Combined with the previous results, we believe that PdMYB161 and PdMYB90 / 167 genes may cause functional dissimilation in the evolutionary process. These results also provide new evidence for the functional evolution of plant homologous genes.