Transgenic rice hybrids that carry the Rf-1 gene at multiple loci show improved fertility at low temperature

• Published in: Plant, cell and environment Vol. 28; no. 4; pp. 425 - 431
• Main Authors: Komori, T, Imaseki, H
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.04.2005; Blackwell; Wiley Subscription Services, Inc
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; booting stage; Classical and quantitative genetics. Population genetics. Molecular genetics; cold stress; cold tolerance; cytoplasmic male sterility; Fundamental and applied biological sciences. Psychology; Generalities. Genetics. Plant material; genetic markers; genetic variation; Genetics and breeding of economic plants; hybrid; hybrids; loci; Molecular genetics; molecular sequence data; nucleotide sequences; Oryza sativa; plant fertility; pollen; pollen fertility; Rf‐1; rice; transgenic plants; Monocotyledones; Seeds; Cold; Genomics; Tolerance; cold tolerance; rice; pollen fertility; Oryza sativa; hybrid; Gene; booting stage; Gramineae; Angiospermae; Spermatophyta; Genetic engineering; Pollen; Rf-1; Low temperature; Cytoplasmic male sterility
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/j.1365-3040.2004.01277.x

By using a genomic fragment that carries the rice (Oryza sativa L.) fertility restorer gene, Rf-1, rice restorer lines harbouring multiple Rf-1 genes on different chromosomes were developed by genetic engineering and crossing. Hybrid lines that were obtained by crossing the restorer lines having two and three Rf-1 genes with a cytoplasmic male sterile (CMS) line had nearly 75 and 87.5% pollen fertility rates under a normal condition, respectively, whereas a conventional hybrid line showed a 50% pollen fertility rate. Furthermore, the seed set percentage under low temperature conditions was much higher in the hybrid lines with multiple Rf-1 genes than the conventional hybrid line. These results indicate that multiplication of the Rf-1 gene conferred cold tolerance at the booting stage to hybrid rice through increasing the potentially fertile pollen grains. This strategy to improve fertility at low temperature of hybrids could be applied to any grain crops that are developed based on CMS and its gametophytic restorer gene, let alone rice.