2个石榴品种果皮花色苷合成相关基因表达分析

Expression Profiles of Anthocyanin Biosynthetic Genes in Two Cultivars of Punica granatum L.

以2个不同红色石榴品种‘红宝石’和‘墨石榴’为试验材料,采用荧光定量PCR方法,分析花色苷合成相关基因CHS、CHI、F3H、DFR、ANS、UFGT等6个基因在果实发育过程中的转录表达特性,同时分析基因表达量与果皮花色苷积累的关系。结果表明:(1)在整个果实发育期内‘墨石榴’花色苷含量明显高于‘红宝石’;随着果实的发育,‘红宝石’果皮中总花色苷含量不断增加,而‘墨石榴’中总花色苷含量初期很高,随后迅速下降,后期维持在较低水平。(2)‘红宝石’中CHS、CHI、F3H、DFR、UFGT等5个基因均在果实发育的早期和晚期出现2个表达高峰,而ANS基因的表达量在整个果实发育期内不断升高;在‘墨石榴’中CHS、CHI、F3H、DFR、ANS等5个基因的表达高峰均出现在早期,随着果实的发育表达量均呈下降变化趋势,但UFGT基因在中期时表达量最高。(3)‘红宝石’石榴的ANS基因表达量与总花色苷含量呈显著正相关,‘墨石榴’中CHS和ANS基因的表达水平与总花色苷含量显著相关。研究认为,花色苷合成相关基因的初期和末期表达差异是2个石榴品种着色差异的主要原因,ANS在‘红宝石’着色中起关键作用,CHS和ANS可能在‘墨石榴’花色苷积累中起重要作用。

Two red pomegranate cultivars‘Hongbaoshi＇and‘Moshiliu＇were sampled as plant materials.The transcriptional characterizations of CHS,CHI,F3H,DFR,ANS,and UFGTinvolved in anthocyanin biosynthesis were monitored by qRT-PCR during fruit development.The relationships between contents of total anthocyanins in fruit peels and transcription abundance of these genes were also analyzed.Results showed that：（1）during fruit development,the content of total anthocyanins in ‘Moshiliu＇was much higher than that in‘Hongbaoshi＇pomegranate.The content of total anthocyanins in‘Hongbaoshi＇increased gradually with fruit development,while in ‘Moshiliu＇,the content of total anthocyanins was high at early stages and then decreased at later periods.（2）In‘Hongbaoshi＇pomegranate,transcripts of CHS,CHI,F3H,DFR,and UFGT were most abundant at early and late stages in fruit development.The transcription level of ANSin ‘Hongbaoshi＇increased gradually and reached the highest amounts at the late phases.In ‘Moshiliu＇cultivar,the transcription levels of all detected genes except UFGT remained high at early stages,and then showed a declining trend afterwards.The expression level of UFGT gene in‘Moshiliu＇reached peak at middle stage.（3）The correlation analysis results showed that a significant positive correlation between ANS abundance and anthocyanins content in ‘Hongbaoshi＇cultivar,while‘Moshiliu＇cultivar,there was strong positive correlation between CHSand ANSlevels and anthocyanins content.It might be concluded that the different red coloration between two pomegranate cultivars was due to the differential expression of the anthocyanin biosynthetic genes at initial and final phases.ANSgene played a key role in‘Hongbaoshi＇coloration,CHSand ANSplayed important roles in anthocyanin accumulation of‘Moshiliu＇pomegranate.