小麦微核心种质γ射线辐射敏感性分析

Radiation Sensitivity Analysis of Wheat Mini Core Collections Based on γ-rays Irradiation

以259个小麦微核心种质为材料进行剂量为0、100、150、250 Gy的60Coγ射线辐照处理,探讨小麦微核心种质的γ射线辐射敏感性分布,以及DNA损伤修复基因TaKu70和TaKu80对辐照的应答模式。结果表明,小麦微核心种质的苗高损伤率与γ射线辐照剂量间存在着3种函数关系:对数、线性、幂函数。以苗高损伤率为50%时的辐照剂量HD50作为主要的辐射敏感性分型指标,分别统计不同函数关系的微核心种质落入不同剂量区间的基因型个数,并依此将259份微核心种质分为敏感型(10)、较敏感型(96)、较钝感型(101)、钝感型(52)。对数函数关系中以敏感型和较敏感型为主,随着γ射线辐照剂量的增加TaKu70和TaKu80基因的相对表达量与对照相比总体升高,但变化不明显;线性函数关系中以较敏感型和较钝感型为主,TaKu70和TaKu80基因的相对表达量与对照相比总体升高,随剂量的增加而逐渐递增;幂函数关系中以较钝感型和钝感型为主,TaKu70和TaKu80基因的相对表达量与对照相比总体升高,但随剂量的增加呈现先增加后降低的趋势,一般相对表达量的峰值出现在150 Gy。

To study the distribution of radiation sensitivity and expression patterns of TaKu70 and TaKu80 genes that are core factors in DNA repair process,259 wheat mini core collection genotypes were irradiated by γ-rays with 0,100,150 and 250 Gy doses. Through germination test,the damage rate of seedling height showed 3 types of function relationships with the doses of γ-rays irradiation： logarithmic,linear and power function. Using HD50 as the measurement of radiation sensitivity,the 259 mini core collection genotypes could be divided into four categories： sensitive（ contained 10 genotypes）,medium sensitive（ contained 96 genotypes）,medium insensitive（ contained101 genotypes）,and insensitive（ contained 52 genotypes）. There were more sensitive and medium sensitive genotypes in the logarithmic function relationship. And the expression levels of TaKu70 and TaKu80 genes were up-regulated by increasing of γ-rays doses compared with 0 Gy,but not affected significantly. There were more medium sensitive and medium insensitive genotypes in the linear function relationship. And the expression levels of TaKu70 and TaKu80 genes were gradually up-regulated by increasing of γ-rays doses compared with 0 Gy. There were more me-dium insensitive and insensitive genotypes in the power function relationship. And the expression levels of TaKu70 and TaKu80 were up-regulated compared with 0 Gy,but up-regulated firstly and then down-regulated with the increasing of γ-rays doses,and the general expression peaked at 150 Gy.