Abstract:

Recent advances in genomic studies and the sequenced genome information have made it possible to utilize phenotypic mutants for characterizing relevant genes at the molecular level and reveal their functions. Various mutants and strains expressing phenotypic and physiological variations provide an indispensable source for functional analysis of genes. Because rice is easy to transform, T-DNA has been used successfully to generate insertional mutant lines. A large rice insertional mutant pool generated with Ac/Ds transposone system derived from maize was established in China National Rice Research Institute. A new delayed growth mutant, named T456, was screened from 45 000 independent Ds transfer lines of rice (Oryza sativa L.). It mainly performed delayed growth，dwarfism，dark green leaf color，as well as large angle of leaf to clum and short length of seminal root, but there were no differences in photosynthesis rate and respiration rate between T456 and wild-type rice cv Zhonghua 11. Genetic analysis showed that the plants with mutant phenotype and wild phenotype in T1 generation fitted to 1:3 and there were no segregation in T₂ generation with mutant phenotype，indicating that the mutant phenotype was controlled by a single recessive gene. Basta determination on the healthy rice leaves in T₁ and F₂ generations showed that the mutant phenotype was co-segregated with the T-DNA. PCR and Southern blotting analysis further confirmed that the mutant phenotype was caused by T-DNA insertion with single copy. This insertional T-DNA mutagenesis will be useful for isolating the tagged gene in rice by Tail-PCR method easily, and for elucidating the gene functions accordingly.

Key words: Rice, Developmental stage, Mutant, T-DNA insertion, Co-segregation, Southern blotting