Expression of CIPK15 Gene in Thai Rice Varieties under Submergence

Abstract

Some rice varieties be able to adapt for germination and growth under submergence since low oxygen condition during germination affect rice growth and productivity. CIPK15 gene is involved in rice germination adaptability under submergence. Therefore, the objective of this study was to evaluate the expression of CIPK15 gene in rice seedling under submergence and non-submergence for 14 days in 11 Thai rice varieties. The experimental design was 2 x 11 factorial in completely randomized design with 3 replications. The resulted found that the expression of CIPK15 gene was significant difference (P<0.05) among 11 rice varieties under submergence. The expression ratio of the CIPK15 gene between submergence and non-submergence classified rice into 2 groups, the first group was RD19 and the second group included Khao Pong Krai, Nam Roo, R258, Khao Dawk Mali105, Niaw Kiaw Ngoo, Pathum Thani1, RD10, RD14, San-pah-tawng1 and Suphan Buri1. Considering the expression of CIPK15 gene, the highest expression ratio of the CIPK15 gene between submergence and non-submergence was found in RD19. The nucleotide sequence analysis of the CIPK15 gene indicated that RD19 rice variety showed different nucleotide sequence compare to the other 10 rice varieties however, displayed similar sequence to the common wild rice (O. rufipogon). While the nucleotide sequence of CIPK15 were similar among the 10 rice varieties. The haplotype network analysis displayed that RD19 was included in the same haplotype with common wild rice (haplotype 1) while the 10 rice varieties were clustered in haplotype 2. Taken together, RD19, a deep-water rice variety, showed adaptability to submergence during germination indicated by displaying high level of relative intensity of CIPK15 gene expression between submergence and non-submergence. The results of this study can be used for developing molecular markers-assisted selection in the submergence tolerant rice breeding program.