矮牵牛BBX基因家族成员鉴定及对不同光质的表达响应

BBX gene family members in Petunia: comparative genome analysis and expression pattern under different light quality conditions

BBXs (B-box zinc finger genes)是植物中一类重要的编码转录因子的基因,它们在控制植物生长发育、响应环境胁迫中起着重要作用。本研究对两个矮牵牛野生种(Petunia inflata和P. axillaris)基因组中的BBXs基因家族成员进行了鉴定和分析;其中在P. axillaris基因组中共发现有29个成员,在P. inflata有32个成员。氨基酸序列比对和进化树分析表明,它们共分化形成了5个亚家族,其中含有2个B-box结构域的有3个亚家族,分别是G1、G2和G4;只有1个B-box结构域的有G3和G5。另外,在G1、G2和G3亚家族中的成员除了含有B-box结构域,在C端还有一个相对保守的CCT结构域。对不同光质条件下矮牵牛花瓣中的BBXs基因进行转录分析,发现共有9个成员出现了差异性表达;其中BBX18、BBX24和BBX25在红光条件下表达明显减弱,与矮牵牛花色积累的表型趋势一致,推测它们可能参与不同光质条件下花青苷的调控过程。

The B-box zinc finger genes(BBXs) encoding a type of zinc finger transcription factors in plants, which play important roles in controlling plant growth development and response to environmental stress. In this study, a total of 29 gene members were identified from the genome of Petunia axillaris and 32 members were from P. inflata. Alignment of their putative encoding amino acids and phylogenetic tree analysis showed that they can be divided into five subfamilies(G1-G5). G1, G2 and G4 members contained two B-box domains, and G3 and G5 members only contained one. In addition to the B-box domain, G1, G2 and G3 members all contained a conserved CCT domain in their C terminal. Transcriptome analysis of these BBXs under different light-quality conditions showed that nine of them were differentially expressed. Among them, BBX18, BBX24 and BBX25 were significantly decreased under the red light condition. Interestingly, their expression pattern was consistent with the flower petals’ pigmentation phenotype, which means that these genes could be involved in the regulation of anthocyanin synthesis in response to different light conditions.