High efficiency transformation and regeneration of four popular restorer lines of Indicarice in southwest China

High efficiency transformation and regeneration of Indicarice is a vital foundation for molecular breeding and function analysis of Indica-specific genes.In this paper,embryogenic callus from four popular Indicarestorer lines in southwest China,Lehui 188,Wanhui 88,Q2and Shuhui 527,were used to explore callus induction,transformation and regeneration by using different combinations of plant hormones in culture media.It was shown that the callus of four lines were best initiated on Nutrient Broth(NB)medium containing 3.0mg/L of 2,4-D with high induction frequency from 75.4%to 93.3%.The differentiation efficiency of Wanhui 88 and Lehui 188 was significantly improved by the combination of 3.0 g/L sorbitol, 5.0mg/L KT,1.0mg/L NAA,3.0mg/L 6-BA and 3.0mg/L 2,4-D,while the differentiation efficiency of Q2was effectively promoted by the combination of 10mg/L KT and 0.4mg/L NAA.The N6and N6D medium combination with the additions of 10mg/L KT and 0.4mg/L NAA was the optimal differentiation medium for Shuhui 527.The plantlet regeneration frequency could reach 38.5%-65.9%,and the observed transformation frequency ranged from 70%to 90%.Together,the highly efficient transformation and regeneration system was established from mature embryo-derived callus of Lehui 188,Wanhui 88,Q2and Shuhui 527.According to the transformation system tested,Arabidopsis heat shock protein gene HSP101was introduced into Wanhui 88and positive transgenic plants were obtained which had improved heat resistance compared to wide type.