转反义trxs基因小麦籽粒中ABA和GAs含量与穗发芽的关系

Relationship between ABA and GAs Contents and Pre-harvest Sprouting in Grains of Transgenic Anti-trxs Gene Wheat

为了揭示反义硫氧还蛋白基因（anti-trxs）在抗穗发芽小麦中的作用机制,探讨转基因小麦籽粒中内源激素ABA和GAs含量变化与穗发芽的关系。以转反义trxs基因两个纯合株系及其未转基因对照小麦品种豫麦18为材料,采用荧光定量RT-PCR、整穗发芽试验和酶联免疫吸附的方法,对小麦灌浆过程中反义trxs基因表达、穗发芽特性及内源激素脱落酸（ABA）和赤霉素（GAs）含量进行了测定。结果表明,在种子形成过程中,反义trxs基因能够正常表达,2个转基因株系中内源trxh基因表达量都明显低于对照;转基因株系籽粒中ABA和ABA/GAs含量显著高于对照,平均分别比对照升高了18.39%和23.47%,而GAs含量在花后15~30天较对照有所降低,平均比对照降低了9.14%;花后20、25、30天,转基因株系的穗粒发芽率显著或极显著低于对照,平均分别比对照下降了49.65%、28.2%、27.23%;相关分析表明,穗发芽率与ABA和ABA/GAs含量均呈显著或极显著负相关,与GAs含量呈正相关。由此推断,反义trxs基因导入抑制了小麦内源同源基因的表达,改变了小麦体内ABA和GAs的平衡,使ABA合成量增加,是导致转基因小麦穗发芽率降低的原因之一。

To investigate the function mechanism of antisens-thioredoxin s （anti-trxs） gene in transgenic wheat,the endogenous trxh gene expression pattern,the contents of endogenous ABA and GAs,pre-harvest sprouting characteristic and their relationship in transgenic line 01TY18-99-8,01TY18-100-2 and non-transgenic cultivar ‘ Yumai 18 ’ were studied by real-time RT-PCR,enzyme linked immunoserbent assay （ELISA） and intact spike sprouting assay.The result indicated that foreign anti-trxs gene could express.During seed filling process,the express amounts of trxh gene in two transgenic line seeds were lower distinctly than non-transgenic seeds.Compared with non-transgenic plant,the ABA and ABA/GAs contents in transgenic lines increased significantly （P 0.01） by 18.39% and 23.47% respectively at 10 — 30 days after anthesis ,while the GAs content decreased averagely by 9.14% at 15 — 30 days after anthesis.The sprouting ratio of seeds on spikes decreased significantly （P 0.01） by 49.65%,28.2%,27.23%,respectively at the periods of 20,25 and 30 day after anthesis.Based on further correlative analysis,the sprouting ratio of spikes were negatively correlated with the contents of ABA and ABA/GAs,and the correlation between the sprouting ratio of spikes and the contents of ABA and ABA/GAs reached a significantly level （P 0.05） or greatly significantly level （P 0.01）.The sprouting ratio of spikes were positively correlated with the GAs contents,but the correlation between the sprouting ratio of spikes and the GAs contents didn ’ t reached a significantly level except for at 30 day after anthesis.Thus it can be concluded that foreign trxs gene expression in transgenic lines maybe regulate the balances of ABA and GAs contents,made ABA level increased and leaded finally to the sprouting ratio of spikes lower.