硫氧还蛋白基因对大麦发芽特性的影响

Effects of trxs Gene on Germination of Transgenic Barley Seeds

对转硫氧还蛋白基因(trxs)的大麦种子进行了生化指标测定及发芽特性研究。结果显示,转基因大麦籽粒中硫氧还蛋白h的活性是非转基因种子的3.3倍;水溶蛋白和醇溶蛋白中巯基含量的比率比非转基因种子都高;发芽时转基因籽粒中α淀粉酶和β淀粉酶活力比非转基因种子高;转基因种子的发芽势也明显高于对照。说明将trxs基因导入大麦能增强种子中硫氧还蛋白h的活性,改变与种子发芽相关的一些重要生化特性,并促进种子发芽。

Thioredoxin h （Trx h） is a small disulfide-containing redox protein. During seed germination Trx h amylase, protease and other enzyme activities can be enhanced and the hydrolysis of the endosperm storage substances such as starch and protein promoted by Trx h, It＇ s very likely to affect the malting barley quality by changing Trx h activity. Thioredoxin s （ trxs ） gene, isolated from Phalaris coerulescens, belongs to thioredoxin （ trx ） gene family. As far as catalysis reduction reaction of S-S is concerned, expression product of trxs gene has the same bio-function as Trx h. Trx h activity may be enhanced and carbon-nitrogen metabolic activity during seed germination promoted and diastatic power （DP） and extract material of malting barley increased by transferring trxs into barley. To achieve barley with higher Trx h activity, trxs gene had been transformed into barley immature embryos and transgenic plants had been obtained via tissue culture in previous study. In this study, biochemical analyses and physiological analyses were carried to find differences between transgenic and non-transgenic seeds. Results were as follows ： （1） Trx h activity in transgenic seeds was 3.3 times as great as that in non-transgenic seeds （Fig. 1）; （2） during germination both a-amylase and D-amylase activities of transgenic seeds were higher than those of CK （Table 1） ; （3） transgenic seeds had higher ratio of reduced sulfhydryl in water soluble protein and alcohol soluble protein （Fig.2）; （4） an enhancement of germinating vigor of the transgenic seeds was also founded （Fig,4） . These results proved that Trx h activity can be enhanced and some important characters related to germination such as amylase activity and reduced storage protein in seeds changed by transferring trxs into barley, which result in more powerful germinating vigor.