Qiao Linyi, Zhang Li, Zhang Xiaojun, Zhang Lei, Li Xin, Chang Jianzhong, Zhan Haixian, Guo Huijuan, Zheng Jun, Chang Zhijian
Department of Biological Sciences, College of Life Science, Shanxi University, Taiyuan, 030006, China.
Shanxi Key Laboratory of Crop Genetics and Molecular Improvement, Institute of Crop Science, Shanxi Academy of Agricultural Sciences, Taiyuan, 030031, China.
J Mol Evol. 2017 Oct;85(3-4):107-119. doi: 10.1007/s00239-017-9810-z. Epub 2017 Oct 30.
The Aux/IAA (IAA) gene family, involved in the auxin signalling pathway, acts as an important regulator in plant growth and development. In this study, we explored the evolutionary trajectory of the IAA family in common wheat. The results showed ten pairs of paralogs among 34 TaIAA family members. Seven of the pairs might have undergone segmental duplication, and the other three pairs appear to have experienced tandem duplication. Except for TaIAA15-16, these duplication events occurred in the ancestral genomes before the divergence of Triticeae. After that point, two polyploidization events shaped the current TaIAA family consisting of three subgenomic copies. The structure or expression pattern of the TaIAA family begins to differentiate in the hexaploid genome, where TaIAAs in the D genome lost more genes (eight) and protein secondary structures (α1, α3 and β5) than did the other two genomes. Expression analysis showed that six members of the TaIAA family were not expressed, and members such as TaIAA8, 15, 16, 28 and 33 exhibited tissue-specific expression patterns. In addition, three of the ten pairs of paralogs (TaIAA5-12, TaIAA15-16 and TaIAA29-30) showed similar expression patterns, and another five paralog pairs displayed differential expression patterns. Phylogenetic analysis showed that paralog pairs with high rates of evolution (ω > ω ), particularly TaIAA15-16 and TaIAA29-30, experienced greater motif loss, with only zero to two interacting IAA proteins. In contrast, most paralogous genes with low ω, such as TaIAA5-12, had more complete motifs and higher degrees of interaction with other family members.
参与生长素信号通路的Aux/IAA（IAA）基因家族在植物生长发育中起着重要的调节作用。在本研究中，我们探究了普通小麦中IAA家族的进化轨迹。结果显示，在34个Ta IAA家族成员中有十对旁系同源基因。其中七对可能经历了片段重复，另外三对似乎经历了串联重复。除了Ta IAA15 - 16，这些重复事件发生在小麦族分化之前的祖先基因组中。在那之后，两次多倍体化事件形成了目前由三个亚基因组拷贝组成的Ta IAA家族。Ta IAA家族的结构或表达模式在六倍体基因组中开始分化，其中D基因组中的Ta IAA失去的基因（八个）和蛋白质二级结构（α1、α3和β5）比其他两个基因组更多。表达分析表明，Ta IAA家族的六个成员不表达，而Ta IAA8、15、16、28和33等成员表现出组织特异性表达模式。此外，十对旁系同源基因中的三对（Ta IAA5 - 12、Ta IAA15 - 16和Ta IAA29 - 30）表现出相似的表达模式，另外五对旁系同源基因则表现出差异表达模式。系统发育分析表明，进化速率较高（ω > ω ）的旁系同源基因对，特别是Ta IAA15 - 16和Ta IAA29 - 30，经历了更多的基序丢失，与IAA蛋白的相互作用仅有零至两个。相比之下，大多数ω值较低的旁系同源基因，如Ta IAA5 - 12，具有更完整的基序，与其他家族成员的相互作用程度更高。
