Identification and molecular analysis of the annexin genes in Cyamopsis tetragonoloba L

Abstract

Annexins are a family of multigene proteins involved in plant development and stress responses. In the current study, the guar transcriptome database yielded a total of five annexin unigenes (named AnnCt1-AnnCt5). The predicted molecular weight of detected AnnCts was estimated to be between 35.22 and 37.03 kDa, with theoretical pIs ranging from 5.97 to 9.15. AnnCts have four annexin repeats that contain endonexin domains with Ca2+-binding sites with 24.44 to 71.74% of amino acid similarity among each other. The coding sequences (CDS) of two of the five guar annexins (AnnCt1 and AnnCt5) were completely cloned and were similar to the ones retrieved. AnnCts were divided into four groups based on their phylogenetic study, indicating evolutionary connections with higher plant annexins and a close relationship with Glycine max. Predominant expression of AnnCt1 followed by AnnCt2 and AnnCt5 were observed more in green organs such mature leaves, shoots, and developing seeds (30DAF) indicated their significant roles. AnnCts genes have respond to drought, salt, cold, and abscisic acid (ABA) treatments showing possible roles in ABA-dependent or independent stress signaling pathways. In-silico analysis of soybean annexin (evolutionary close to guar annexin) predicted interactions with proteins that are possibly involve in organogenesis, transportation, and transcription regulation. The purified rAnnCt1 protein has shown DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) radical scavenging activity in-vitro. Our findings show that AnnCts are often guar annexins, that may play critical roles in different guar organs as well as contribute to stress tolerance and, its purified rAnnCt1 protein has antioxidant activity.