硫素营养水平对大豆籽粒OAS-TL表达的影响

Effect of expression OAS-TL on soybean seeds under sulfur regulation

大豆氧乙酰丝氨酸(硫醇)裂解酶(OAS-TL)催化半胱氨酸合成,是硫素代谢的关键酶。试验以东农46(高油型)和黑农35(高蛋白型)为材料,检测鼓粒期后大豆籽粒OAS-TL在3个不同硫水平(0、0.02、0.08g·kg-1土)下的生理特性,鉴定克隆了该酶基因并分析了其调控表达情况。结果表明,①OAS-TL活性随生育进程推进持续下降,2个品种籽粒OAS-TL活性表现为S20高于S0和S80处理;鼓粒前期施硫效果大于后期;②通过同源克隆获得一个编码OAS-TL基因的cDNA序列,全长1059bp,ORF长855bp,编码34.2ku的蛋白质;③半定量RT-PCR显示OAS-TL稳定态mRNA在籽粒发育早期表达较强,且处理间差异明显,发育后期表达水平逐渐降低。不同硫素处理间OAS-TL的表达有差异,S20上调表达高于S0和S80。

The objective of this study was to study and characterize O-acetyI-L-serine（thiol）-Iyase （OAS-TL） which is a key enzyme in the pathway of sulfur metabolism that catalyzes the last step in the production of cysteine. Two cultivars, Dongnong46 （high-oil）, Heinong35 （high-protein） were tested in this research by means of pots experiments with three sulfur application levels（0, 0.02, 0.08 g·kg^-1 soil） to study the effects of sulfur on the seeds of soybeans at the stage of drum particle. And than, cloned and characterized the expression OAS-TL. The results showed that： ① The activity OAS-TL were higher at the early stage of seeds development and than declined along with the seeds maturity process. The treatment of S20 showed higher activity than those of So and S80; The effect of each sulfur treatment showed more different at the early stage than the late stage;② A full-length cDNA clone encoding OAS-TL was obtained by homology cloning. The nucleotide sequenced covers 1 059 bp and nucleotides analysis of the cDNA revealed a single region of ORF of 855 bp encoding a 34.2 ku protein; ③RT-PCR analysis revealed that the OAS-TL mRNA was abundant and showed significant difference under each treatment at the early stage of seed development and than declined along with the seeds maturity process. The OAS-TL mRNA were different at each of the treatment, totally, the mRNA level of the treatment of S20 was more higher than those of S0 and S80.