水稻幼苗期低温胁迫的生理响应及转录组分析.

[Objective] The present paper aimed to study the physiological changes and gene dynamic changes of rice under low temperature stress, which was helpful to analyze the physiological basis and molecular mechanism of rice response to low temperature stress, and laid a theoretical foundation for screening suitable rice variety with cold tolerance and studying how to improve the cold-tolerance inheritance of rice. [Method] Taking three rice varieties with different cold-tolerance levels, P427 ( strong cold-tolerance), Nipponbare (cold-tolerance), 9311 (cold-sensitivity) as testing materials, and using method of phenotype combined with physiochemical index, the paper studied the effect of 3 -4 °C low temperature stress on phenotype, chlorophyll content and electric conductivity, and used RNA-Seq to analyze enrichment pathways and the dynamic change of gene response to low temperature stress. [Result] The rice variety with strong cold-tolerance P427 showed strong adaptability to low temperature. It maintained higher chlorophyll content under low-temperature stress, and its chlorophyll content before low temperature treatment, on the third day of low temperature treatment, on the third day of recovery growth was 29. 64, 29. 30 and 27. 96 µgig, respectively. Its electric conductivity on the first day, third day, fifth day of low-temperature was 10. 39%, 13. 08% and 17. 04%, and its membrane system had the lightest damage. A large number of genes were differentially expressed in both cold tolerant and cold sensitive varieties under low temperature induction, and the number of differentially expressed genes ( DEGs) continued to increase with the extension of low temperature treatment time,but the number of specific DEGs in P427 decreased from 2408 to 1717. In addition, only 576 specific genes of P427 were differentially expressed from 1 days to 3 days under low temperature treatment. GO and KEGG enrichment analysis showed that the specific DEGs of P427 after low temperature treatment were mainly enriched in metabolic pathways such as biosynthesis of secondary metabolites, plant hormone signal transduction and phenylpropane biosynthesis. [ Conclusion] There may be differences in cold-tolerance response genes and regulatory mechanisms among cultivars with different cold tolerance. There was a set of cold-tolerance response genes in P427 cultivar with strong cold tolerance, which was different from that in Nipponbare and 9311. Plant hormone signal transduction and phenylalanine metabolism were significantly affected by low temperature stress in seedling rice. P427 may respond to cold tolerance of seedling rice through metabolic pathways such as biosynthesis of secondary metabolites, plant hormone signal transduction and phenylpropane biosynthesis pathway. [ABSTRACT FROM AUTHOR]