RNAi抑制过氧化物酶基因Rsprx1表达促进萝卜花青素的积累

RNA Interference of Peroxidase Gene Rsprx1 Increased Anthocyanidin Accumulation in Chinese Red Radish

过氧化物酶是一类广泛存在于生物中的氧化还原酶,被认为参与植物花青素的代谢.本实验利用RNAi技术,干扰萝卜过氧化物酶基因Rsprx1表达.结果表明,RNAi干扰载体的萝卜植株中过氧化物酶基因(Rsprx1)表达被抑制,过氧化物酶活性显著降低,过氧化物酶同工酶条带减少;而花青素含量在处理第9 d达到最大值;花青苷种类和含量有较大变化:天竺葵素-3-阿魏酰葡糖苷-5-丙二酰基葡糖苷、天竺葵素-3-ρ-香豆酰二葡糖苷-5-丙二酰基葡糖苷、天竺葵素-3-阿魏酰二葡糖苷-5-丙二酰基葡糖苷和天竺葵素-3-二ρ-香豆酰二葡糖苷-5-丙二酰基葡糖苷含量升高;天竺葵素-3-二葡糖苷-5-葡糖苷、天竺葵素-3-葡糖苷-5-葡糖苷和天竺葵素-3-酰化二葡糖苷-5-葡糖苷含量降低;花青素合成相关基因(Chs、Chi、Dfr、F3h和Ldox)及转录因子(Tt8)的mRNA表达水平在RNAi处理后早期有明显上调.这些结果均表明,萝卜过氧化物酶Rsprx1参与花青素的合成代谢.

Peroxidase （POD） is an oxidoreductase that participates the process of anthocyanidin metabolism. We knocked down the expression of peroxidase gene （Rsprxl） in Chinese red radish （Raphanus sativus L. ） by RNA interference （RNAi）. The peroxidase activity was significantly reduced in the RNAi group than that in the controls as shown by the weaker POD isoenzyme bands. The anthocyanin content increased and reached the maximum on day 9 in the Rsprxl knockdown group. The types of anthocyanin were also changed. The contents of pelargonidin 3-feruloyl glucoside-5-malonlyl glueoside, pelargonidin 3-ρ-coumaroyl diglucoside-5-malonoyl glucoside, pelargonidin3-feruloyl diglucoside-5-malonoyl glueoside and pelargonidin 3-ρ-coumaroyl p-coumaroyl diglucoside-5-malonoyl glucoside were increased, and the content of pelargonidin 3-diglucoside-5-glucoside, pelargonidin 3- glucoside-5-glucoside and pelargonidin 3-acyl diglucoside-5- glucoside were decreased as detected using high-performance liquid chromatography. The mRNA levels of anthocyanin synthesis genes such as chalcone synthase, chaleone isomerase, dihydroflavonol 4- reductase, flavanone 3-hydroxylase, leucoanthocyanidin dioxygenase and transcription factors （Tt8） were significantly increased at the earlystage during RNAi treatment. These results indicated that the peroxidase gene Rsprxl might be involved in anthocyanin synthetic metabolism.