Abstract:

【Objective】 Previous studies focused on the analysis of RVA profile in rice at the level of the subspecies or varieties (Oryza sativa L.) in which there were differences in genetic background. In this study, antisense waxy homozygous transgenic lines were used to analyze the differences in RVA characteristic values among the lines with different amylase contents in an effort to eliminate the influence of different genetic backgrounds and to more clearly understand the relationship between the amylose content and RVA characteristic value. 【Method】 Anther culture pure lines containing antisense waxy gene were generated by Agrobacterium tumefaciens mediated co-transformation and followed by anther culture in transgenic rice variety. The amylose content and RVA profile were determined in the anther culture lines, and the effects of the amylose content on RVA characteristic value were analyzed under the same genetic background conditions through the RVA profile graphic comparison and the significant determination of RVA eigen value. 【Result】 Seventy-seven pure lines of anther culture that contained only antisense waxy gene but no hygromycin resistance marker were obtained from the transgenic plant offspring of Wu Yunjing No.7 rice variety (O. sativa L. subsp. japonica cv.). Through the dertermination of the amylose content to the T1H1 and T1H2, it was showed that 19 lines had the levels of amylose content similar to the control (16.0%), and that 50 lines were 1%–5% lower than that of control in the amylose content, and some of 30 lines had the amylose content within 11.0%﹣13.9%, and that 8 lines had the amount of amylase content reduced to 3.1%–4.0%. The results of the analysis of the rice starch RVA profile in the pure lines with different amylose contents indicated that there were two kinds of RVA profile: the lines with 3.1%﹣4.0% of amylose content were distinctly different from other lines and conventional glutinous rice. The results of comparison of the lines with same RVA profile to the lines with different amylose content, also showed that the lines with lower amylose content had a distinguished RVA profile with the curve of increasing gradually in finally, but no exceeding the first apex. In significance tests for the characteristic values of RVA profile in the lines with different amylose content, there were five characteristic values of RVA remarkably different among the lines with 3.1%–4.0% of amylose content compared with two other groups, and that there were three characteristic values remarkably different among the lines wiht 11.0%﹣13.5% of amylose content compared with control group. An optimized mathematical model, which characterized the relationships between the amylose content and RVA eigenvalue, was established in this study. From this model, it clearly indicated that the parameters PeT and SBV were more related to the amylose content. 【Conclusion】 Introduction of antisense waxy gene could lead to a reduced amylose content in rice. Anther culture could result in producing pure lines more quickly. The amylose content differences not only affected the characteristic value of RVA but caused different RVA profile as well.

Key words: antisense waxy gene, transgee, amylose, RVA profile, rice