Abstract:

【Objective】 The common tobacco (Nicotiana tabacum) variety VAM was highly resistant to PVY. A PVY resistance-related gene NtPsaN was cloned from VAM. The sequence features, evolutionary relationships and expression characteristics of NtPsaN were analyzed and the molecular mechanism of tobacco resistance response was studied, and thus provide a theoretical foundation for PVY-resistant tobacco breeding. 【Method】 A virus resistance-related gene fragment was screened through Suppression Subtractive Hybridization (SSH) and cDNA chip technologies, the full-length cDNA sequence was cloned through RACE, the conserved domains and sequence features of the gene were analyzed by bioinformatic methods, a neighbor-joining phylogenetic tree was constructed using the MEGA4.0 program and its relative expression characters were explored by real-time PCR. 【Result】 The tobacco resistance-related gene, named NtPsaN, was cloned. The gene possesses conserved domains of PsaN superfamily. The open reading frame (ORF) of the full length cDNA was 507 bp in length, encoding 168 amino acids. The PsaN subunit phylogenetic tree was constructed. The results of real-time PCR showed that the expression of NtPsaN was obviously up-regulated in leaves infected with PVY. 【Conclusion】 A PVY resistance-related gene NtPsaN was cloned from tobacco, and it was induced by PVY infection. The NtPsaN gene may play a critical role in the PVY-resistance of tobacco.

Key words: PVY, NtPsaN, phylogenetic tree, gene expression