Cloning and Expression Analysis of NtSAMT1 Gene from Narcissus tazetta var. chinensis

Abstract:

In order to understand molecular mechanism of floral scent formation of Narcissus tazetta var. chinensis, based on a fragment cDNA from different florescence suppression subtractive hybridization (SSH), the salicylic acid carboxyl methyltransferase gene was cloned from N. tazetta var. chinensis by RACE and RTPCR, named NtSAMT1 (GenBank No. JX273470). The full length of NtSAMT1 cDNA was 1323 bp with an 1131 bp ORF, which encoded a protein of 376 amino acids with a conservative domain of methyltransf_7 superfamily. NtSAMT1 is similar to SAMT of Clarkia breweri (1m6eX) in three-dimensional structure. The NtSAMT1 is predicted an unstable protein. Phylogenetic analysis showed that SAMT in Narcissus tazetta var. chinensis had close relationship to that in Oryza sativa Japonia (BAD12867). Prokaryotic expression showed that recombinant pGEX-NtSAMT1 had highly expression in NE. coil BL21. Semi-quantitative RT-PCR revealed that NtSAMT1 could expression in all tissues of buds, the expression in stamens and pistils was the highest at first day after blooming and its expression disappeared at the eighth day after blooming. The expression of NtSAMT1 could be detected in scape, petal, corolla, stamen and pistil of the first day of blooming, expression of NtSAMT1 in the first day flowers was in order as stamen, pistil > scape > petal, corolla.

Key words:Narcissus tazetta var. Chinensis;SAMT;Gene expression