Genome-Wide Identification of Peanut KCS Genes Reveals That AhKCS1 and AhKCS28 Are Involved in Regulating VLCFA Contents in Seeds
Genome-Wide Identification of Peanut KCS Genes Reveals That AhKCS1 and AhKCS28 Are Involved in Regulating VLCFA Contents in Seeds
复制标题
花生 KCS 基因的全基因组鉴定揭示 AhKCS1 和 AhKCS28 参与调节种子中的 VLCFA 含量
DOI：
10.3389/fpls.2020.00406
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发表时间：
2020-05-07
影响因子：
5.6
通讯作者：
Liao, Boshou
中科院分区：
文献类型：
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作者：
Huai, Dongxin;Xue, Xiaomeng;Liao, Boshou
花生（Arachis hypogaea L.）是世界上重要的油料作物。与其他常见的食用植物油相比，花生油含有更高含量的饱和脂肪酸（SFA），其中约20-40%是极长链脂肪酸（VLCFA）。为了了解这种油谱的基础，我们询问了花生β-酮脂酰辅酶A合酶（KCS）的基因，该酶是VLCFA生物合成中的关键酶。在组装的花生基因组中共鉴定出30个AhKCS基因。基于转录组数据，克隆了9个在发育种子中具有高表达水平的AhKCS基因，并在酵母中表达。所有这些AhKCSs可以产生VLCFA，但导致不同的配置文件，表明AhKCSs催化脂肪酸延伸具有不同的底物特异性。在具有不同VLCFA含量的六个花生种质系的发育种子中对这九个AhKCS基因的表达水平进行了分析。在这些基因中，AhKCS 1或AhKCS 28的表达水平比任何其它AhKCS的表达水平高4-10倍。而只有AhKCS 1和AhKCS 28的表达量与VLCFA含量呈显著正相关，表明AhKCS 1和AhKCS 28参与了花生种子VLCFA含量的调控。进一步的亚细胞定位分析表明AhKCS 1和AhKCS 28定位于内质网。在拟南芥中过量表达AhKCS 1或AhKCS 28可增加VLCFAs的含量，特别是极长链饱和脂肪酸（VLCSFAs）的含量。综上所述，AhKCS 1和AhKCS 28可能是花生种子中VLCFA生物合成调控的关键基因，可用于改善花生的保健营养品质。
The peanut (Arachis hypogaea L.) is an important oilseed crop worldwide. Compared to other common edible vegetable oils, peanut oil contains a higher content of saturated fatty acids (SFAs), approximately 20-40% of which are very long chain fatty acids (VLCFAs). To understand the basis for this oil profile, we interrogated genes for peanut beta-ketoacyl-CoA synthase (KCS), which is known to be a key enzyme in VLCFA biosynthesis. A total of 30 AhKCS genes were identified in the assembled genome of the peanut. Based on transcriptome data, nine AhKCS genes with high expression levels in developing seeds were cloned and expressed in yeast. All these AhKCSs could produce VLCFAs but result in different profiles, indicating that the AhKCSs catalyzed fatty acid elongation with different substrate specificities. Expression level analysis of these nine AhKCS genes was performed in developing seeds from six peanut germplasm lines with different VLCFA contents. Among these genes, the expression levels of AhKCS1 or AhKCS28 were, 4-10-fold higher than that of any other AhKCS. However, only the expression levels of AhKCS1 and AhKCS28 were significantly and positively correlated with the VLCFA content, suggesting that AhKCS1 and AhKCS28 were involved in the regulation of VLCFA content in the peanut seed. Further subcellular localization analysis indicated that AhKCS1 and AhKCS28 were located at the endoplasmic reticulum (ER). Overexpression of AhKCS1 or AhKCS28 in Arabidopsis increased the contents of VLCFAs in the seed, especially for very long chain saturated fatty acids (VLCSFAs). Taken together, this study suggests that AhKCS1 and AhKCS28 could be key genes in regulating VLCFA biosynthesis in the seed, which could be applied to improve the health-promoting and nutritional qualities of the peanut.