高温胁迫下SmCCoAOMT正调控茄子果皮着色

咖啡碱-辅酶A-O-甲基转移酶（caffeoyl-CoA-O methyltransferase, CCoAOMT）是木质素合成途径的关键酶,但其在逆境胁迫中也发挥重要作用。根据茄子基因组数据设计引物克隆了CCoAOMT,命名为SmCCoAOMT,其最大阅读框为564 bp,编码187个氨基酸,相对分子质量为20.95 ku。生物信息学分析发现SmCCoAOMT与其他植物的CCoAOMT序列同源性高达90.67%,同时具有CCoAOMT的全部保守序列。对其在不同果皮颜色茄子品种及35 ℃高温下果实不同发育时期的表达进行了qRT-PCR分析,结果表明SmCCoAOMT在果皮颜色深的茄子品种中的相对表达量高于在果皮颜色浅的品种中的表达量,说明SmCCoAOMT的表达量与茄子果色呈正相关;与常温对照相比,在花后10和20 d时,高温胁迫下SmCCoAOMT的表达量都显著下降,尤其是在花后10 d时,表达量仅为对照的9.23%,说明SmCCoAOMT表达量显著下调可能是导致果皮颜色变浅的原因之一。结果推测SmCCoAOMT在高温胁迫下茄子果皮颜色变浅的过程中起正调控作用。

SmCCoAOMT Positively Regulates the Peel Coloring in Eggplant under High Temperature Stress

Caffeoyl-CoA-O methyltransferase (CCoAOMT) is a key enzyme in the lignin synthetic pathway and also plays an important role in abiotic stresses. According to the eggplant reference genome, SmCCoAOMT was cloned from eggplant. The maximum opening reading frame (ORF) of SmCCoAOMT was 564 bp, encoding 187 aa and its relative molecular weight was 20.95 ku. The bioinformation analysis indicated that SmCCoAOMT showed 90.67% sequence identity with CCoAOMTs of other plants and had all the conservative sequences in CCoAOMT. The expressions in eggplants with different peel colors and at different stages of fruit development were analyzed by qRT-PCR. The results showed that the expression of SmCCoAOMT was significantly higher in purplish red and blackish purple peels than in white and green peels, which was positively correlated with peel color. Comparing to control, on the 10 ^th and 20 ^th days after flowering (10DAF, 20DAF), the expressions of SmCCoAOMT were significantly down-regulated under high temperature (HT) stess, especially on 10DAF, the expression decreased to 9.23%. Which might lead to the light peel color. The results suggested that SmCCoAOMT positively regulated the peel coloring in eggplant under HT stress.