Variation of DNA methylation in genome of different cotton varieties under salt stress

Functional Genomics

poster

Zhang, Mi; Cai, Xixi; Fu, Rong; Huang, Jie ; Xie, Xiaoling; Wang, Baohua

Fu, Rong

Wang, Baohua

Agricultural production is often influenced by non-biological stresses, wherein salt stress is just one of the major non-biological stresses of agricultural production. As the most important source of textile fiber, cotton not only has strong salt tolerance, which makes it one of the superior crops adapting to saline-alkali soil, but also has high economic benefits. In this research, methylation-sensitive amplification polymorphism (MSAP) method based on high performance capillary electrophoresis (HPCE) was used to analyze DNA methylation level in four cotton varieties, including two salt-tolerant varieties CCRI 35 and CCRI 07, and two salt-sensitive varieties CCRI 12 and Xinyan 96-48, so as to discuss the molecular mechanism of salt tolerance in cotton. The results showed that all kinds of variation of DNA methylation happened in the four cotton varieties under salt stress, including hypermethylation, hypomethylation and other patterns; hypermethylation happened at a significantly higher rate than that of hypomethylation in the two salt-tolerant cotton varieties, CCRI 35 and CCRI 07. However, in CCRI 12 hypomethylation happened at a significantly higher rate than that of hypermethylation, whereas no significant difference was detected between different variation types in Xinyan 96-48. DNA methylation level significantly increased under salt stress in salt-tolerant varieties CCRI 35 and CCRI 07, whereas there was no significant difference in salt-sensitive varieties CCRI 12 and Xinyan 96-48. Our results suggested that salt-tolerant cotton might have the potential mechanism of increasing methylation level when responding to salt stress, which might partly explain salt stress tolerance in cotton. Preliminary cloning and analysis of methylated DNA sequences showed that hypermethylation happened in some MYB transcription factor related genes, which was further validated by qRT-PCR.