Molecular cloning, expression and in silico analyses of calcium-dependent protein kinase 2 (CDPK2) in potato (Solanum tuberosum L.)

Abstract

In plants, calcium-dependent protein kinases (CDPKs) play crucial role in the regulation of growth and development in response to various stresses. They act as sensor-transducers in decoding the calcium (Ca2+) ions associated with multiple signal transduction pathways. The plant CDPK isoforms are encoded by the nuclear multigene families. Some CDPK isoforms were reported earlier in potato; but their three-dimensional (3-D) structures were not predicted. Based on the RT-PCR approach using tuber total RNA, a 1560-bp cDNA clone encoding 515-aa CDPK2 isoform (designated StCDPK2) was isolated and characterized from the potato cultivar Kufri Chipsona-1(KC-1). A thorough sequence analysis revealed both sequence identities and crucial motifs in the potato CDPKs. Semi-quantitative RT-PCR approach was adopted to show the expression patterns of StCDPK2 in different potato organs grown under field condition. The three-dimensional (3-D) structures of potato CDPK1−3 were predicted by a composite approach using ab initio modeling, and further validated and assessed by Ramachandran plot analyses. In addition, a number of the CDPK isoforms were retrieved from the potato genome sequence database; their probable biochemical properties and functional aspects were predicted based on both bioinformatics tools and published reports.