沙棘LBD基因家族鉴定及其在花芽发育过程中的表达分析

LBD gene family in Hippophae rhamnoides: identification and expression pattern during flower bud development

摘要:

外侧器官边界域(lateral organ boundaries domain,LBD)转录因子广泛存在于高等植物中，并在植物生长发育和逆境胁迫等过程中发挥了非常重要的作用。沙棘(Hippophae rhamnoides L.)作为一种抗旱、耐寒、耐盐碱的灌木，具有一定的生态价值和经济价值。为了分析LBD基因家族在中国沙棘雌雄花芽发育过程中的作用，本研究利用生物信息学方法从沙棘全基因组数据中鉴定出了11个LBD基因。LBD基因家族不均匀分散在5条染色体上，编码159−302个氨基酸，分子质量为18 249.91−33 202.01 Da。亚细胞定位预测表明蛋白质分布于细胞核或叶绿体中；LBD序列较为保守，具有高度相似的基序、基因结构和蛋白质三维结构；将沙棘与拟南芥(Arabidopsis thaliana)、大麦(Hordeum vulgare)的LBD基因进行系统发育分析发现，HrLBD基因家族均可细分为Class Ⅰ和Class Ⅱ两大亚家族；转录组及反转录实时荧光定量聚合酶链式反应(reverse transcription-polymerase chain reaction,RT-qPCR)结果显示，HrLBD基因在沙棘雄性花芽发育过程中表达量更高，并随着花芽发育过程表达量逐渐升高，推测HrLBD基因在特定时期影响沙棘雄性花芽发育。本研究为阐明HrLBD基因在沙棘雌雄花芽生长发育中的作用和性别分化机制奠定了理论基础。

关键词:沙棘;外侧器官边界域(LBD)基因家族;花芽发育;基因表达;反转录实时荧光定量聚合酶链式反应

Abstract:

Lateral organ boundaries (LOB) domain (LBD) genes encode a family of transcription factors ubiquitous in higher plants, playing crucial roles in the growth, development, and stress responses. Hippophae rhamnoides, known for its drought, cold, and saline-alkali tolerance, offers significant economic benefits and ecological values. Utilizing the whole genome data and bioinformatics approaches, this study identified and analyzed the LBD gene family in H. rhamnoides. Additionally, we examined the expression pattern of HrLBD genes by integrating the transcriptome data from male and female flower buds in development. Eleven LBD genes were identified in H. rhamnoides, and these genes were distributed on five chromosomes. The HrLBD proteins showed the lengths ranging from 159 aa to 302 aa, the molecular weights between 18 249.91 Da and 33 202.01 Da, and the subcellular localization in the nucleus or chloroplasts. LBD protein domains and gene structures were highly conserved, featuring similar motifs. The phylogenetic analysis of HrLBD genes and the LBD genes in Arabidopsis thaliana and Hordeum vulgare revealed that HrLBD genes falled into two major categories: Class I and Class II. The transcriptome data and RT-qPCR showed that HrLBD genes were highly expressed in male flower buds, with up-regulated expression levels throughout bud development, indicating a role in the specific stage of male flower bud development. This study lays a theoretical foundation for exploring the roles of HrLBD genes in the growth, development, and sex differentiation of H. rhamnoides flower buds.

Key words:Hippophae rhamnoides;lateral organ boundaries (LOB) domain (LBD) gene family;flower bud development;gene expression;reverse transcription-polymerase chain reaction