类黄酮合成关键基因MeF3H在木薯块根采后腐烂中的功能分析OACSTPCD

In order to understand the function of MeF3H in postharvest physiological deterioration(PPD)of cassava tuberous roots,'South China No.9'variety('SC 9')was used as the material.The expression of MeF3Hin leaves,petioles,stems,fragility embryogenic callus(FEC),flowers,axillary buds,fibrous roots,tuberous roots and PPD process were analyzed,and the subcellular localization of MeF3H were determined.Virus induced gene silencing(VIGS)technology was used to silencing MeF3H,and the effects on flavonoid content and PPD were analyzed.The results showed that MeF3H was highly expressed in axillary buds and fibrous roots,and MeF3H was localized in the cytoplasm,the expression of MeF3H and content of flavonoid in tuberous roots were increased with PPD process.The results of qRT-PCR analysis indicated that the silence efficiency of MeF3H was 39％to 67％.Compared with control,the flavonoid content in the leaves and tuberous roots of silenced plants were significantly decreased(P＜0.05),and there is a significant positive correlation between MeF3H expression and flavonoid content(P＜0.05).The degree of PPD was significantly deepened in silenced cassava plants,with a root degeneration rate was over 50％at 3 d after harvest,while the deterioration rate in control plant was 36.67％.In conclusion,there is a significantly positive correlation between MeF3H expression and flavonoid content,PPD tolerance of turberus roots(P＜0.05).Silencing MeF3H gene significantly accelerates PPD occurrence in cassava tuberous roots.