[Determination of amylose content in transgenic progenies containing an antisense waxy gene and identifying of pure lines in indica rice].

Abstract

Through genetic transformation mediated by Agrobacterium tumefaciens, an antisense waxy gene was introduced into Longtefu B line, a male sterile maintainer line in indica (Oryza sativa L.). Thirty transgenic plants showed integration of antisense waxy gene into the genome as determined by PCR assay, and twenty eight were confirmed by Southern blotting. T1 seeds from twenty one transgenic plants showed a marked decrease of amylose content, ranging from 3%-13% less than control, and seeds from some transgenic lines exhibited typical waxy phenotype. Six transgenic lines were selected to examine the amylose content in different generations. In the T4 generation, two homozygous lines, Long 3-1-1-1 and Long 5-8-2-1, were selected, with amylose content of 15.9% and 8.4% respectively. The amylose content in these lines is in consistent with the decrease of the accumulation of Wx protein as determined by SDS-PAGE electrophoresis. Cross and subsequent backcross of Long 3-1-1-1 and Long 5-8-2-1 with the Longtefu mare sterile line were performed to determine the changes of amylose content in F1 and B1F1 seeds. The results showed an average amlyose content of 21.4% in F1 seeds with Long 3-1-1-1 as a parent, while only 13.6% with Long 5-8-2-1 as a parent. In addition, the average amylose contents in B1F1 seeds were 17.1% and 9.3% respectively. Our results indicated that during the fertility transfer in the male sterile line, stable transgenic lines with medium or low contents of amylose had direct effects on amylose content in F1 seeds.