In silico analysis of cis-acting regulatory elements in 5ʹ regulatory regions of Ca2+/cation antiporters gene family in Zea mays L

Systemic and cellular homeostasis is very important for proper functioning of living organisms, including plants..The role of Ca2+ as a secondary messenger in signal transduction in response to external and internal stimuli like plant growth nutrients, light, fungal elicitors and various abiotic stresses is well known.The modulation in Ca2+ concentration across the cell membrane is basically mediated by three classes of transporters-Ca2+-ATPases (PMCAs), Ca2+ permeable channels, and Ca2+/cationantiporters (CaCAs), which function in combination with each other. CaCA proteins basically form a composite superfamily, which consists of five different families of exchanger proteins-YRBG, Na+/Ca2+ exchanger (NCX), Na+/Ca2+, K+ exchanger(NCKX), cation/ Ca2+ exchanger(CCX),and H+/cation exchanger (CAX), which are classified on the basis of their function and evolutionary relationship.Identifying this gene family and examining thepromoterregion to determine the cis-regulatory elements of the response to hormones and stressescould be the first step to understand the functionof this gene family in maize (Zea mays). In the present studyby usingHMM profile and blastP search 14ZmCaCAgenes identifedin maize genome databasewhich were classified in to seven ZmCAX, six ZmCCX and oneZmMHXgenes families based on their evolutionary relation with earlier reported CaCAgenes in Arabidopsis and rice.Unlike rice and Arabidopsis, which have two and one genes of NCLsubgroup respectively, Promoter analysisof these genes using PlantCare database showed the presence of several cis-regulatory elements related to stress and hormone responsewithin the 1.5ʹ kbp of 5′ regulatory region.Overall, 19 different typesstresses and hormones responsive cis element with varying abundance were identified in the promoter region of these genes.The most abundance regulatory elements are MBS,CGTCA-motif and TGACG-motif whichform 10/24%,15/12% and 15/12/%of regulatoryelements and act in response to drought,methyl jasmonate and methyl jasmonate respectively.Ofthe other important cis-elemen could bementioned to ERA, GC-motif, ABREand TCA-element.This result revealedthat cis-acting regulatory elements that possibly are involved in the expression and regulation of CaCA gene families in maize during environmental stress conditions