Genome-wide identification and expression profiling of annexins in Brassica rapa and their phylogenetic sequence comparison with B. juncea and A. thaliana annexins

• Thirteen genes encode annexin proteins in B. rapa.
• Whole genome triplication caused the expansion of annexin family in B. rapa.
• Annexin family shows shrinking at subgenomic level in B. rapa.
• Subgenomic paralogs of B. rapa annexins show variation in their gene structure.
• BrANNs expression is regulated by different hormones and stress treatments.

Abiotic stresses affect the yield of crop plants worldwide. Plant species have evolved in such a way that they are able to cope up with these stresses to a certain extent. For further increases in yield and productivity in plants under stress conditions, there is a need to understand the mechanisms and the genes involved in their stress signaling and the information so generated can be utilized in abiotic stress improvement in crops. Brassica species and their different morphotypes are used worldwide as vegetables and oilseed crops. One important species of Brassica known as Brassica rapa (= Brassica campestris) has different morphotypes like turnip, Chinese cabbage and yellow mustard. Recent genome sequencing of one of its morphotypes — Chinese cabbage, an important vegetable crop in China, has opened up the avenues for a comparative study of other morphotypes of this species. Yellow mustard, a morphotype of B. rapa is an important oil yielding crop in India. It is mainly grown in the northern parts of India and is very sensitive to salt and drought stress. The genome sequencing of B. rapa subsp. Chifu (Chinese cabbage) would help in the genome wide analysis of different genes important in development and stress tolerance. Annexins, a protein family important for plant growth and development under normal and stress conditions, are ubiquitously found in plant and animal kingdoms and other unicellular organisms. In this study, we have identified the different annexin sequences present in the genome of B. rapa subsp. Chifu and conducted a genome wide expression analysis of different annexin members in an Indian variety (Yellow Sarson) of B. rapa. Our study showed the differential expression of the gene family under normal and stress conditions underlying their involvement in different stages. Bra034402 with homology to AnnAt1 and AnnBj1 got significantly upregulated in all hormone and stress treatments where as others showed differential up- or downregulation.