基于转录组分析的火炬松次生木质部萜类生物合成相关基因的鉴定、表达和系统发育分析

对火炬松次生木质部进行了转录组分析，以了解参与萜类生物合成的基因。共有372个单基因被鉴定为油树脂生产的关键基因，包括ATP结合（ABC）转运蛋白、细胞色素P450（CYP）蛋白家族和萜类主干生物合成酶的基因。选择参与萜类生物合成途径的六个关键基因进行多序列比对、保守基序预测、系统发育和表达谱分析。所有六个基因的蛋白质序列都表现出较高的序列保守性，在萜类生物合成途径中上游基因相对比下游基因保守性更高。这些序列的N-末端区域的保守性低于C-末端，因为N-末端在长度和组成上都非常不同。系统发育分析表明，大多数基因起源于物种分化后的基因复制，部分基因表现出不完全的谱系分类。此外，表达谱分析表明，所有六个基因在高油脂产量阶段都表现出高表达水平。

Transcriptomic analysis was conducted on the secondary xylem of Pinus taeda to identify genes involved in terpenoid biosynthesis. A total of 372 unigenes were identified as key genes associated with oleoresin production, including genes encoding ATP-binding cassette (ABC) transporters, cytochrome P450 (CYP) protein family members, and enzymes involved in terpenoid backbone biosynthesis. Six key genes participating in the terpenoid biosynthetic pathway were selected for multiple sequence alignment, conserved motif prediction, phylogenetic analysis, and expression profile analysis. The protein sequences of all six genes exhibited high overall sequence conservation, with upstream genes in the terpenoid biosynthetic pathway showing relatively higher conservation than downstream genes. The N-terminal regions of these sequences displayed lower conservation than their C-terminal counterparts, as the N-termini vary considerably in both length and amino acid composition. Phylogenetic analysis indicated that most of these genes originated from gene duplication events that occurred after species divergence, while some genes exhibited incomplete lineage sorting. Additionally, expression profile analysis revealed that all six genes showed high expression levels during the high oleoresin yield stages.