The novel Solanum tuberosum calcium dependent protein kinase, StCDPK3, is expressed in actively growing organs

• Published in: Planta 2012-12, Vol.236 (6), p.1831-1848
• Main Authors: Grandellis, Carolina, Giammaria, Verónica, Bialer, Magalí, Santin, Franco, Lin, Tian, Hannapel, David J., Ulloa, Rita M.
• Format: Article
• Language: English
• Subjects: 5' Untranslated Regions; Agriculture; Agrobacterium tumefaciens; Amino Acid Sequence; Antibodies; Biodegradation; Biological and medical sciences; Biomedical and Life Sciences; Calcium; Calcium signalling; Ecology; Exons; Forestry; Fundamental and applied biological sciences. Psychology; Gels; Gene Expression Regulation, Enzymologic - genetics; Gene Expression Regulation, Plant; Genes; Glutamine; Introns; Kinetics; Leaves; Life Sciences; Light effects; Molecular Sequence Data; myristoylation; Organ Specificity; Original Article; palmitoylation; Phosphorylation; Phylogeny; Plant Leaves - enzymology; Plant Leaves - genetics; Plant Leaves - growth & development; Plant Leaves - physiology; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Sciences; Plant Tubers - enzymology; Plant Tubers - genetics; Plant Tubers - growth & development; Plant Tubers - physiology; Plants; Plants, Genetically Modified; Proline; Promoter Regions, Genetic - genetics; Promoters; Protein Isoforms; Protein kinase; Protein kinase C; Protein Kinases - genetics; Protein Kinases - metabolism; Proteins; Recombinant Fusion Proteins; Regulatory sequences; RNA, Plant - genetics; Roots; Sequence Alignment; Sequence Analysis, DNA; Signal Transduction; Solanum tuberosum; Solanum tuberosum - enzymology; Solanum tuberosum - genetics; Solanum tuberosum - growth & development; Solanum tuberosum - physiology; Stolons; Stress, Physiological - genetics; Transgenic plants; Tubers
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-012-1732-9

Calcium-dependent protein kinases (CDPKs) are key components of calcium regulated signaling cascades in plants. In this work, isoform StCDPK3 from Solanum tuberosum was studied and fully described. StCDPK3 encodes a 63 kDa protein with an N-terminal variable domain (NTV), rich in pralines and glutamines, which presents myristoylation and palmitoylation consensus sites and a PEST sequence indicative of rapid protein degradation.StCDPK3 gene (circa 11 kb) is localized in chromosome 3, shares the eight exons and seven introns structure with other isoforms from subgroup and contains an additional intron in the 5'UTR region. StCDPK3 expression is ubiquitous being transcripts more abundant in early elongating stolons (ES), leaves and roots, however isoform specific antibodies only detected the protein in leaf particulate extracts. The recombinant 6xHis-StCDPK3 is an active kinase that differs in its kinetic parameters and calcium requirements from StCDPKl and 2 isoforms. In vitro, StCDPK3 undergoes autophosphorylation regardless of the addition of calcium.The StCDPK3 promoter region (circa 1,800 bp) was subcloned by genome walking and fused to GUS. Light and ABRE responsive elements were identified in the promoter region as well as elements associated to expression in roots.StCDPK3 expression was enhanced by ABA while GA decreased it. Potato transgenic lines harboring StCDPK3 promoter::GUS construct were generated by Agrobacterium tumefaciens mediated plant transformation. Promoter activity was detected in leaves, root tips and branching points, early ES, tuber eyes and developing sprouts indicating that StCDPK3 is expressed in actively growing organs.