RESUMO
BACKGROUND: Miniature inverted repeat transposable element (MITE) is one type of transposable element (TE), which is largely found in eukaryotic genomes and involved in a wide variety of biological events. However, only few MITEs were proved to be currently active and their physiological function remains largely unknown. RESULTS: We found that the amplicon discrepancy of a gene locus LOC_Os01g0420 in different rice cultivar genomes was resulted from the existence of a member of Gaijin-like MITEs (mGing). This result indicated that mGing transposition was occurred at this gene locus. By using a modified transposon display (TD) analysis, the active transpositions of mGing were detected in rice Jiahua No. 1 genome under three conditions: in seedlings germinated from the seeds received a high dose γ-ray irradiation, in plantlets regenerated from anther-derived calli and from scutellum-derived calli, and were confirmed by PCR validation and sequencing. Sequence analysis revealed that single nucleotide polymorphisms (SNPs) or short additional DNA sequences at transposition sites post mGing transposition. It suggested that sequence modification was possibly taken place during mGing transposition. Furthermore, cell re-differentiation experiment showed that active transpositions of both mGing and mPing (another well studied MITE) were identified only in regenerated plantlets. CONCLUSIONS: It is for the first time that mGing active transposition was demonstrated under γ-ray irradiation or in cell re-differentiation process in rice. This newly identified active MITE will provide a foundation for further analysis of the roles of MITEs in biological process.
Assuntos
Diferenciação Celular/genética , Elementos de DNA Transponíveis/genética , Sequências Repetidas Invertidas/genética , Repetições Minissatélites/genética , Oryza/citologia , Oryza/genética , Sequência de Bases , Diferenciação Celular/efeitos da radiação , Sequência Conservada/genética , Técnicas de Cultura , Evolução Molecular , Raios gama , Germinação/genética , Germinação/efeitos da radiação , Íntrons/genética , Dados de Sequência Molecular , Oryza/crescimento & desenvolvimento , Oryza/efeitos da radiação , Plântula/citologia , Plântula/genética , Plântula/crescimento & desenvolvimento , Plântula/efeitos da radiaçãoRESUMO
Genotypic and environmental variation in Cd, Cr, As, Ni and Pb concentrations of grains, and the relationships between these heavy metals and Fe, Zn were investigated using 9 rice genotypes grown in 6 locations for two successive years. Significant genotypic variation was detected in the five heavy metal concentrations in grains, indicating the possibility to reduce the concentration of these heavy metals in grains through breeding approach. The environmental effect varied with metal, with Pb and Ni having greater variation than the other three metals. There was significant genotype-environment (location) interaction of the concentrations of all five heavy metals in grains, suggesting the importance of cultivar choice in producing rice with low heavy metal concentrations in grains for a given location. Correlation analysis showed that Cd and As, Cr and Ni, and As and Pb concentrations in rice grains were closely associated, and that Ni concentration in grains was negatively correlated with Zn concentration.
