Molecular cloning and characterization of five annexin genes from Indian mustard (Brassica juncea L. Czern and Coss)

Plant annexins constitute a multigene family having suggested roles in a variety of cellular processes including stress responses. We have isolated and characterized five different cDNAs of mustard, Brassica juncea (AnnBj1, AnnBj2, AnnBj3, AnnBj6 and AnnBj7) encoding annexin proteins using a RT-PCR/RACE-PCR based strategy. The predicted molecular masses of these annexins are ∼36.0 kDa with acidic pIs. At the amino acid level, they share high sequence similarity with each other and with annexins from higher plants. Phylogenetic analysis revealed their evolutionary relationship with corresponding orthologous sequences in Arabidopsis and deduced proteins in various plant species. Expression analysis by semi-quantitative RT-PCR revealed that these genes are differentially expressed in various tissues. The expression patterns of these genes also showed regulation by various stress conditions such as exposure to signaling molecules, salinity and oxidative stress and wounding. Additionally, the in silico promoter analysis (of AnnBj1, AnnBj2 and AnnBj3) showed the presence of different cis-responsive elements that could respond to various stress conditions. These results indicate that AnnBj genes may play important roles in adaptation of plants to various environmental stresses.