School of Agriculture and Food Science, Zhejiang A & F University, Lin'an, Hangzhou, Zhejiang 311300, China.
BMC Plant Biol. 2012 Jun 13;12:85. doi: 10.1186/1471-2229-12-85.
In plants, sucrose synthase (Sus) is widely considered as a key enzyme involved in sucrose metabolism. Several paralogous genes encoding different isozymes of Sus have been identified and characterized in multiple plant genomes, while limited information of Sus genes is available to date for cotton.
Here, we report the molecular cloning, structural organization, phylogenetic evolution and expression profiles of seven Sus genes (GaSus1 to 7) identified from diploid fiber cotton (Gossypium arboreum). Comparisons between cDNA and genomic sequences revealed that the cotton GaSus genes were interrupted by multiple introns. Comparative screening of introns in homologous genes demonstrated that the number and position of Sus introns are highly conserved among Sus genes in cotton and other more distantly related plant species. Phylogenetic analysis showed that GaSus1, GaSus2, GaSus3, GaSus4 and GaSus5 could be clustered together into a dicot Sus group, while GaSus6 and GaSus7 were separated evenly into other two groups, with members from both dicot and monocot species. Expression profiles analyses of the seven Sus genes indicated that except GaSus2, of which the transcripts was undetectable in all tissues examined, and GaSus7, which was only expressed in stem and petal, the other five paralogues were differentially expressed in a wide ranges of tissues, and showed development-dependent expression profiles in cotton fiber cells.
This is a comprehensive study of the Sus gene family in cotton plant. The results presented in this work provide new insights into the evolutionary conservation and sub-functional divergence of the cotton Sus gene family in response to cotton fiber growth and development.
在植物中，蔗糖合酶（Sus）被广泛认为是参与蔗糖代谢的关键酶。在多个植物基因组中已经鉴定和表征了几个编码不同同工型的 Sus 基因的同源基因，但迄今为止，棉花的 Sus 基因信息有限。
在这里，我们报告了从二倍体纤维棉（Gossypium arboreum）中鉴定出的七个 Sus 基因（GaSus1 至 7）的分子克隆、结构组织、系统进化和表达谱。cDNA 和基因组序列之间的比较表明，棉花 GaSus 基因被多个内含子打断。同源基因中内含子的比较筛选表明，Sus 基因在棉花和其他更远缘的植物物种中的内含子数量和位置高度保守。系统进化分析表明，GaSus1、GaSus2、GaSus3、GaSus4 和 GaSus5 可以聚集成一个双子叶 Sus 组，而 GaSus6 和 GaSus7 则均匀地分为另外两个组，其中包括双子叶和单子叶物种的成员。七个 Sus 基因的表达谱分析表明，除了 GaSus2 之外，其在所有检测的组织中均未检测到转录物，而 GaSus7 仅在茎和花瓣中表达，其他五个同源基因在广泛的组织中均有差异表达，并在棉花纤维细胞中表现出发育依赖性的表达谱。
这是对棉花植物 Sus 基因家族的全面研究。本研究结果为棉花 Sus 基因家族在应对棉花纤维生长和发育过程中的进化保守和亚功能分化提供了新的见解。
