Regulation of polygalacturonase-inhibitory proteins in plants is highly dependent on stress and light responsive elements

Abstract

PG inhibiting proteins (PGIPs) are extracellular plant proteins capable of inhibiting fungal endoPGs. The identification of cis-regulatory elements is one of the major challenges in bioinformatics and integrates comparative, structural, and functional genomics. We have detected cis-acting upstream regulatory elements of PGIP-encoding genes, based on sequence analysis in seven different plant species at PLACE and PlantCARE. The upstream sequences of PGIPs contain different regulatory elements such as TATA box, CAAT box, ABRE box, ERE box, wound responsive elements, drought response elements etc., which help in induction of gene expression during plant growth and development, and biotic and abiotic stress. On the basis of the analysis of the regulatory elements we confirm the assigned function of PGIPs in plants like Lycopersicon esculentum, Arabidopsis thaliana, Oryza sativa cv.japonica, Vitis venifera, Brassica napus, Brassica rapa and Medicago sativa. We have also identified the presence of the most important elements, at a high frequency, responsive to light apart from wounding, salicylic acid, abscisic acid, fungal elicitors, ethylene in the upstream sequences across genera providing a link to the light and stress mediated signaling in plant defense responses.