[Show abstract][Hide abstract] ABSTRACT: Hybrid rice plays an important role in China's aim to improve rice production as it accounts for some 50% of rice planting
area but produces about 60% of the total rice grain. However, the existing three-line system used in hybrid rice production
has its limitations. The two-line system, which makes use of photoperiod-sensitive genic male-sterile (PGMS) and thermo-sensitive
genic male-sterile (TGMS) lines to generate the male-sterile parental line, was developed to overcome some of these limitations.
The sterility of the male-sterile line of two-line hybrid rice, however, fluctuates when the temperature-sensitive phase of
fertility encounters abnormal low temperatures during hybrid seed production, which induces selfing and decreases the purity
of hybrid. We describe here the strategy of utilizing a herbicide resistance gene in two-line hybrid rice to eliminate this
fluctuation in the sterility of the P/TGMS lines during hybrid seed production and reports the development of the herbicide
resistance restorer line Bar68-1 and its herbicide-resistant early season hybrid rice Xiang125s/Bar68-1. When the restorer
line and its derived hybrid are herbicide resistant, the selfed seeds can be removed easily from the hybrid by herbicide spraying.
A herbicide resistance gene bar was transferred into a restorer line by particle bombardment. The resulting transgenic restorer line Bar68-1 and its hybrid
Xiang125s/Bar68-1 inherited stable herbicide resistance. The purity of Xiang125s/Bar68-1 was increased by spraying the seed
bed with herbicide, which resulted in a significant increase in yield, grain quality, and disease resistance in comparison
to the controls in a regional trial.
No preview · Article · Sep 2007 · Molecular Breeding
[Show abstract][Hide abstract] ABSTRACT: A plant expression vector harboring four antifungal genes was delivered into the embryogenic calli of '9311', an indica restorer line of Super Hybrid Rice, via modified biolistic particle bombardment. Southern blot analysis indicated that in the regenerated hygromycin-resistant plants, all the four antifungal genes, including RCH10, RAC22, beta-Glu and B-RIP, were integrated into the genome of '9311', co-transmitted altogether with the marker gene hpt in a Mendelian pattern. Some transgenic R1 and R2 progenies, with all transgenes displaying a normal expression level in the Northern blot analysis, showed high resistance to Magnaporthe grisea when tested in the typical blast nurseries located in Yanxi and Sanya respectively. Furthermore, transgenic F1 plants, resulting from a cross of R2 homozygous lines with high resistance to rice blast with the non-transgenic male sterile line Peiai 64S, showed not only high resistance to M. grisea but also enhanced resistance to rice false smut (a disease caused by Ustilaginoidea virens) and rice kernel smut (another disease caused by Tilletia barclayana).
No preview · Article · Mar 2007 · Science in China Series C Life Sciences