拟南芥纤维素合酶基因时空表达模式与功能预测

纤维素是细胞壁的主要组成成分, 研究纤维素合成可以从源头上解决关于高效降解纤维素的问题。该研究通过综合拟南芥(Arabidopsis thaliana)纤维素合酶基因(AtCESA)家族的进化和芯片表达分析及根据拟南芥全生育期GUS染色结果分析纤维素合酶基因的时空表达模式, 发现拟南芥纤维素合酶基因AtCESA1, 3, 6以及AtCESA4, 7, 8分别参与细胞壁初生壁和次生壁的合成并存在明显的共表达现象。其中, AtCESA1, 3, 6在全生育期表达, AtCESA4, 7, 8主要在根、茎和叶脉等次生壁细胞中表达。AtCESA5和AtCESA6、AtCESA2和AtCESA9以及AtCESA1和AtCESA10等基因对均有基因重复作用。根据AtCESA家族基因表达模式和分子演化关系可以推测, AtCESA5对AtCESA6以及AtCESA9对AtCESA2可能分别存在功能冗余。此外, AtCESA9的表达具明显的组织特异性。上述研究结果为深入认识拟南芥纤维素合酶基因的功能奠定了基础。

Expression Profiling and Functional Prediction of Arabidopsis AtCESA Genes

Cellulose is a major structural component of the plant cell wall. Thus, understanding cellulose biosynthesis is important in plant biology and biomass production. In this study, we analyzed the phylogenetics of Arabidopsis cellulose synthesis genes (AtCESA) and their expression using the microarray data from NCBI. Furthermore, we analyzed the expression of 10 AtCESA promoter:GUS reporter genes in different vegetative and reproductive growth stages of Arabidopsis. Our results showed that AtCESA1, -3, and -6 or -6-like protein genes were probably required for primary cell-wall complexes, whereas AtCESA4, -7, and -8 protein genes were possibly involved in secondary cell-wall complexes. AtCESA1, -3, and -6 show high global expression in all tissues, whereas AtCESA4, -7, -8 are highly expressed in root, stem and leaf vein. We found 3 segmental duplication genes (AtCESA5/6, AtCESA2/9 and AtCESA1/10); AtCESA5 may be partially redundant with AtCESA6. In addition, AtCESA9 showed tissue-specific expression in meristems and flowers and may be partially redundant with AtCESA2. AtCESA genes may be important for primary and secondary cell-wall formation during different developmental stages in Arabidopsis and in different organs.