Hou Xiao-Jin, Li Si-Bei, Liu Sheng-Rui, Hu Chun-Gen, Zhang Jin-Zhi
Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, China.
PLoS One. 2014 Nov 6;9(11):e112375. doi: 10.1371/journal.pone.0112375. eCollection 2014.
MYB family genes are widely distributed in plants and comprise one of the largest transcription factors involved in various developmental processes and defense responses of plants. To date, few MYB genes and little expression profiling have been reported for citrus. Here, we describe and classify 177 members of the sweet orange MYB gene (CsMYB) family in terms of their genomic gene structures and similarity to their putative Arabidopsis orthologs. According to these analyses, these CsMYBs were categorized into four groups (4R-MYB, 3R-MYB, 2R-MYB and 1R-MYB). Gene structure analysis revealed that 1R-MYB genes possess relatively more introns as compared with 2R-MYB genes. Investigation of their chromosomal localizations revealed that these CsMYBs are distributed across nine chromosomes. Sweet orange includes a relatively small number of MYB genes compared with the 198 members in Arabidopsis, presumably due to a paralog reduction related to repetitive sequence insertion into promoter and non-coding transcribed region of the genes. Comparative studies of CsMYBs and Arabidopsis showed that CsMYBs had fewer gene duplication events. Expression analysis revealed that the MYB gene family has a wide expression profile in sweet orange development and plays important roles in development and stress responses. In addition, 337 new putative microsatellites with flanking sequences sufficient for primer design were also identified from the 177 CsMYBs. These results provide a useful reference for the selection of candidate MYB genes for cloning and further functional analysis forcitrus.
MYB家族基因广泛分布于植物中，是参与植物各种发育过程和防御反应的最大转录因子家族之一。迄今为止，关于柑橘的MYB基因报道较少，表达谱分析也很少。在此，我们根据甜橙MYB基因（CsMYB）家族成员的基因组基因结构及其与拟南芥直系同源基因的相似性，对177个成员进行了描述和分类。根据这些分析，这些CsMYB被分为四组（4R-MYB、3R-MYB、2R-MYB和1R-MYB）。基因结构分析表明，与2R-MYB基因相比，1R-MYB基因含有相对较多的内含子。对其染色体定位的研究表明，这些CsMYB分布在9条染色体上。与拟南芥的198个成员相比，甜橙中的MYB基因数量相对较少，这可能是由于与基因启动子和非编码转录区域中重复序列插入相关的旁系同源基因减少所致。CsMYB与拟南芥的比较研究表明，CsMYB的基因重复事件较少。表达分析表明，MYB基因家族在甜橙发育过程中具有广泛的表达谱，在发育和应激反应中发挥重要作用。此外，还从177个CsMYB中鉴定出337个新的假定微卫星，其侧翼序列足以用于引物设计。这些结果为柑橘克隆候选MYB基因的选择和进一步的功能分析提供了有用的参考。
