College of Agronomy and Biotechnology, Chongqing Rapeseed Engineering Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, China.
College of Agronomy and Biotechnology, Chongqing Rapeseed Engineering Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, China.
Gene. 2020 Jul 15;747:144674. doi: 10.1016/j.gene.2020.144674. Epub 2020 Apr 15.
Very long chain fatty acids (VLCFAs) that are structural components of cell membrane lipid, cuticular waxes and seed oil, play crucial roles in plant growth, development and stress response. Fatty acid elongases (FAEs) comprising KCS and ELO, are key enzymes for VLCFA biosynthesis in plants. Although reference genomes of Brassica napus and its parental speices both have been sequenced, whole-genome analysis of FAE gene family in these Brassica speices is not reported. Here, 58, 33 and 30 KCS genes were identified in B. napus, B. rapa and B. oleracea genomes, respectively, whereas 14, 6 and 8 members were obtained for ELO genes. These KCS genes were unevenly located in 37 chromosomes and 3 scaffolds of 3 Brassica species, while these ELO genes were mapped to 19 chromosomes. The KCS and ELO proteins were divided into 8 and 4 subclasses, respectively. Gene structure and protein motifs remained highly conserved in each KCS or ELO subclass. Most promoters of KCS and ELO genes harbored various plant growth-, phytohormone-, and stress response-related cis-acting elements. 20 SSR loci existed in the KCS and ELO genes/promoters. The whole-genome duplication and segmental duplication mainly contributed to expansion of KCS and ELO genes in these genomes. Transcriptome analysis showed that KCS and ELO genes in 3 Brassica species were expressed in various tissues/organs with different levels, whereas 1 BnELO gene and 6 BnKCS genes might be pathogen-responsive genes. The qRT-PCR assay showed that BnKCS22 and BnELO04 responded to various phytohormone treatments and abiotic stresses. This work lays the foundation for further function identification of KCS and ELO genes in B. napus and its progenitors.
长链脂肪酸（VLCFAs）是细胞膜脂质、角质层蜡和种子油的结构组成部分，在植物生长、发育和应激反应中起着至关重要的作用。脂肪酸延长酶（FAE）包括 KCS 和 ELO，是植物中 VLCFA 生物合成的关键酶。尽管油菜和其亲本种的参考基因组都已测序，但这些油菜种的 FAE 基因家族的全基因组分析尚未报道。在这里，在油菜、白菜和甘蓝基因组中分别鉴定了 58、33 和 30 个 KCS 基因，而 ELO 基因则分别获得了 14、6 和 8 个成员。这些 KCS 基因不均匀地位于 3 个油菜种的 37 条染色体和 3 个支架上，而这些 ELO 基因则定位在 19 条染色体上。KCS 和 ELO 蛋白分别分为 8 个和 4 个亚类，每个 KCS 或 ELO 亚类的基因结构和蛋白基序都高度保守。KCS 和 ELO 基因的启动子中存在各种与植物生长、植物激素和应激反应相关的顺式作用元件。KCS 和 ELO 基因/启动子中存在 20 个 SSR 位点。全基因组复制和片段复制主要导致这些基因组中 KCS 和 ELO 基因的扩张。转录组分析表明，3 种油菜种中的 KCS 和 ELO 基因在不同组织/器官中以不同水平表达，而 1 个 BnELO 基因和 6 个 BnKCS 基因可能是病原体响应基因。qRT-PCR 分析表明，BnKCS22 和 BnELO04 对各种植物激素处理和非生物胁迫有响应。这项工作为进一步鉴定油菜及其祖先中 KCS 和 ELO 基因的功能奠定了基础。
