The insecure problems of seed production have seriously hampered the healthy and sustainable development of two-line hybrid rice.The safety issues on seed production of two-line hybrid rice and current research situation were pointed out in this paper.The three main reasons for unsafety in seed production of twoline hybrid rice were unsuitable site selection,high critical sterility-inducing temperature and the drift of critical temperature.In this paper,strategies and measures were put forward based on many years of practice.It could minimize the risk in seed production of two-line hybrid rice by selecting dual-purpose genic male sterile line with lower critical sterility-inducing temperature and long lower temperature resistant time.Based on the climate data and climatic demands of the ＂three safe-periods＂ in seed production,a new idea for determining appropriate bases and periods for seed production was proposed by using computer technology,which solved the aimless selection of sites and periods for the seed production of two-line hybrid rice.Besides,we established a system of single plant selection and identification method and original seed propagation with cyclic cold water,which could reduce the generation number of original seed propagation in seed production and avoid the drift of critical sterility-inducing temperature.This paper improved the seed production safety in the three aspects of seed nature,seed source and seed production site.
水稻OsSGL(Oryza sativa stress tolerance and grain length)基因表达响应多种非生物逆境,参与调控水稻产量及耐旱性。该基因CDS全长768 bp,编码一个包含DUF1645(Domain of unknown function protein family 1645)结构域的功能蛋白。生物信息学分析预测显示该蛋白分子量为26.73 kD,理论等电点为9.35,为亲水性蛋白且没有跨膜区域,蛋白二级结构中α螺旋占15.69%,β转角占3.14%,延伸链占14.51%,无规则卷曲占66.67%。OsSGL基因CDS序列中稀有密码子的比例高达29.69%,且有多个串联稀有密码子。为进一步在生化水平研究OsSGL蛋白,本研究拟在原核表达系统中大量表达、纯化并鉴定His标签融合表达的Os-SGL蛋白。在不改变氨基酸序列的前提下,通过全基因合成技术,根据大肠杆菌密码子偏好性对OsSGL CDS序列进行优化、合成并连接到pET-32a表达载体中;然后将重组质粒pET-32a-OsSGL转化大肠杆菌,经体外表达条件优化大量合成融合His标签表达的OsSGL蛋白。结果显示,OsSGL基因在大肠杆菌中可实现诱导表达,融合蛋白分子质量约为45.7 kD。最优诱导表达温度、时间、IPTG浓度和摇床转速分别为16℃、16 h、0.5 mmol/L和120 r/min。利用His抗体进行Western blotting进一步检测到纯化的His-OsSGL融合蛋白。OsSGL蛋白体外表达体系的建立有利于在生化水平上深入解析OsSGL参与的信号调控通路。
