Li Wei, Xu Hanyun, Liu Ying, Song Lili, Guo Changhong, Shu Yongjun
Key Laboratory of Molecular Cytogenetic and Genetic Breeding of Heilongjiang Province, College of Life Science and Technology, Harbin Normal University, Harbin 150025, China.
Genes (Basel). 2016 Apr 4;7(4):13. doi: 10.3390/genes7040013.
Mitogen-activated protein kinase kinase kinase (MAPKKK) is a component of the MAPK cascade pathway that plays an important role in plant growth, development, and response to abiotic stress, the functions of which have been well characterized in several plant species, such as Arabidopsis, rice, and maize. In this study, we performed genome-wide and systemic bioinformatics analysis of MAPKKK family genes in Medicago truncatula. In total, there were 73 MAPKKK family members identified by search of homologs, and they were classified into three subfamilies, MEKK, ZIK, and RAF. Based on the genomic duplication function, 72 MtMAPKKK genes were located throughout all chromosomes, but they cluster in different chromosomes. Using microarray data and high-throughput sequencing-data, we assessed their expression profiles in growth and development processes; these results provided evidence for exploring their important functions in developmental regulation, especially in the nodulation process. Furthermore, we investigated their expression in abiotic stresses by RNA-seq, which confirmed their critical roles in signal transduction and regulation processes under stress. In summary, our genome-wide, systemic characterization and expressional analysis of MtMAPKKK genes will provide insights that will be useful for characterizing the molecular functions of these genes in M. truncatula.
丝裂原活化蛋白激酶激酶激酶（MAPKKK）是MAPK级联途径的一个组成部分，在植物生长、发育以及对非生物胁迫的响应中发挥重要作用，其功能在拟南芥、水稻和玉米等多种植物中已得到充分表征。在本研究中，我们对蒺藜苜蓿中的MAPKKK家族基因进行了全基因组和系统的生物信息学分析。通过搜索同源物，共鉴定出73个MAPKKK家族成员，它们被分为MEKK、ZIK和RAF三个亚家族。基于基因组复制功能，72个蒺藜苜蓿MAPKKK基因分布在所有染色体上，但它们在不同染色体上聚类。利用微阵列数据和高通量测序数据，我们评估了它们在生长和发育过程中的表达谱；这些结果为探索它们在发育调控，特别是在结瘤过程中的重要功能提供了证据。此外，我们通过RNA测序研究了它们在非生物胁迫下的表达，这证实了它们在胁迫下信号转导和调控过程中的关键作用。总之，我们对蒺藜苜蓿MAPKKK基因的全基因组、系统表征和表达分析将为阐明这些基因在蒺藜苜蓿中的分子功能提供有用的见解。
