Cloning and analysis of promoter elements of a Ser/Thr protein kinase gene homologue from Piper colubrinum Link.

Abstract

Serine/Threionine (Ser/Thr) protein kinases are multifarious phosphorylation enzymes which also play a central role in signalling events following pathogen recognition in plants. The present study describes cloning and characterisation of upstream promoter region of a Ser/Thr protein kinase (STPK) gene from <em>Piper colubrinum</em> (<em>PcSTPK</em>), a wild species highly resistant to fungal pathogens in the <em>Piper </em>germplasm. The gene was found to be pathogen responsive when challenged with oomycete pathogen &ndash; <em>Phytophthora capsici</em>. Transcript abundance of <em>PcSTPK</em> was determined by quantitative real time-polymerase&nbsp; chain reaction (qRT-PCR) which demonstrated maximum transcript accumulation of <em>PcSTPK</em> in inflorescence, followed by leaf, stem and root tissues. Inoculation of leaf tissues with the oomycete pathogen <em>Phytophthora capsici</em>, also induced significant transcript accumulation of <em>PcSTPK </em>in the plant. Genome walking methodology was adopted to clone upstream promoter elements of <em>PcSTPK</em>. <em>In silico</em> analysis revealed the presence of regulatory elements for light responsiveness, meristem and endosperm expression in addition to various hormone responsive elements. Our results suggest that <em>PcSTPK</em> along with its <em>cis</em>-regulatory elements has a role in modulation of plant stress response.