油菜素内酯合成和信号转导基因在马铃薯块茎贮藏期间的表达变化及对萌芽的影响

摘要

为探明油菜素内酯BR在块茎萌芽中的作用,建立更有效的种薯催芽调控体系,选择了休眠期不同的3个品种,利用qRT-PCR分析与BR合成、信号转导、调控有关的9个基因在贮藏期间及抑芽处理下的表达模式;同时检测BR类似物24-表油菜素内酯(24-eBL)及其与赤霉素GA3对块茎萌芽的影响.结果表明,涉及BR合成的4个基因表达量均随贮藏时间延长升高,短休眠品种升高的时间点早于中、长休眠品种;信号转导及调控基因中BRI1和CYCD3的变化与合成基因相似,BSK和TCH4的表达量则在中、长休眠期品种中保持恒定.抑芽处理在贮藏前期能刺激这些基因的表达升高,但之后都迅速下降并保持低水平.转录因子BZR1在各品种中以及抑芽处理下均没有明显变化.24-eBL利于块茎解除休眠,但不促进芽的伸长生长,与GA3互配效果更佳,单株块茎增重37.92%~98.41%.结论表明,BR合成和信号转导是块茎从休眠向萌芽转变的必经生理过程,它与GA3互配用于催芽更利于种薯萌芽的整齐、健壮并促进块茎形成.%To explore the role of brassinosteroid (BR) in tuber sprouting and establish effective sprouting regulation system for seed potato, three varieties and sprouting-inhibitor treatments were used to analyze expression characteristics of nine genes related to BR synthesis, signal transduction and regulation during storage. Effects of BR analogue 24-epibrassinolide (24-eBL) and gib-berellin (GA3) on tuber sprouting were also studied. The transcript levels of four genes involved in BR synthesis increased with prolonging storage time, and the time points at which the expression levels began to increase in variety with short dormancy pe-riod were earlier than those in varieties with middle or long dormancy period. The expression patterns of BRI1 and CYCD3 were similar to those of synthetic genes while BSK and TCH4 remained constant in varieties with middle or long dormancy period. Sprouting-inhibitors stimulated transcripts of those genes to elevate in the earlier stage of storage, then rapidly decline and stay low levels. There was no significant expression change of transcription factor BZR1 in varieties and sprouting-inhibitor treatments during storage. BR analogue 24-eBL was favorable to tuber dormancy release but shoot growth. The tuber weight per plant treated with 24-eBL and GA3 mixture increased by 37.92% to 98.41% compared with CK. The conclusion, BR synthesis and its signal transduction are essential physiological processes from dormancy to sprouting in potato tuber. Mixture of 24-eBL and GA3 can facilitate uniformity of seed potato sprouting, stronger growth and better tuberization.