山核桃(Carya cathayensis)与油棕(Elaeis guineensis)成油基因的比较

A Comparison in Oil Synthesis-related Genes between Carya cathayensis and Elaeis guineensis

山核桃是木本油料树种中含油率极高的经济树种。为了识别山核桃成油的关键基因,本研究将山核桃种子生长发育期胚转录组数据与油棕中果皮发育期转录组数据进行了比对分析。结果发现山核桃与油棕比对上的脂类代谢及碳水化合物代谢基因比例很高,其中有15个脂类代谢基因在油棕中有表达,而在山核桃中表达量极低;有35个脂类代谢基因在山核桃中相对表达量较高,在油棕中相对表达量较低,但只有14个基因与种子成油有关。有13个碳水化合物代谢相关基因在油棕中表达,而在山核桃中表达量低或并不是各时间点都能检测到;有26个基因在山核桃中表达,而在油棕中表达量低或未检测到,且所有这些基因均与脂肪酸合成的碳源供应有关。山核桃胚中识别的这些基因有3个基因的表达与含油率变化趋势一致,且在山核桃和油棕中的表达模式相似,但只有基因OBO(编码Oil-body oleosin,油体油菜素)表达量很高;油棕中高表达的基因山核桃中有8个,但它们的表达量均不如基因OBO。研究说明不同油料物种的成油相关基因表达有异同,基因OBO对山核桃高油脂的积累具有特殊的作用。

Hickory(Carya cathayensis)is a non-timber tree species with high oil contents in seeds.A comparison between transcriptome data of a developing embryo in hickory and those of developing mesocarp in oil palm(Elaeis guineensis)was made to mine oil synthesis-related genes in hickory.The result shows that the percentage of the genes that were associated with lipid metabolism and carbohydrate metabolism and comparable between hickory and oil palm was pretty high.Fifteen lipid metabolism-associated genes were expressed in oil palm but their expression was very low in hickory;and thirty-five lipid metabolism-associated genes were expressed at a relatively high level in hickory but low in oil palm,out of which only fourteen genes were related to oil synthesis in seeds.Thirteen carbohydrate metabolism-associated genes were expressed in oil palm but they were expressed low or were not detectable in hickory at some temporal points;and twenty-six genes were expressed in hickory but they were expressed low or were not detectable in oil palm,all of which were associated with carbon supply in the synthesis of fatty acids.Among all the genes identified in the embryo of hickory,three genes,which had an expression mode similar to that of oil palm,were expressed in correspondence with changes in oil contents of a seed,but only gene OBO(Encoding oil-body oleosin)was highly expressed;and expression of eight genes identified in hickory that were expressed high in oil palm was not as high as that of OBO.These results reveal that oil-synthesis genes in various oil crops were expressed differently and OBO might play a special role in the oil accumulation in hickory.