Genomic and functional characterization of StCDPK1.
StCDPK1 is a calcium dependent protein kinase expressed in tuberizing potato stolons and in sprouting tubers. StCDPK1 genomic sequence contains eight exons and seven introns, the gene structure is similar to Arabidopsis, rice and wheat CDPKs belonging to subgroup IIa. There is one copy of the gene per genome and it is located in the distal portion of chromosome 12. Western blot and immunolocalization assays (using confocal and transmission electron microscopy) performed with a specific antibody against StCDPK1 indicate that this kinase is mainly located in the plasma membrane of swelling stolons and sprouting tubers. Sucrose (4-8%) increased StCDPK1 protein content in non-induced stolons, however the amount detected in swelling stolons was higher. Transgenic lines with reduced expression of StCDPK1 (beta 7) did not differ from controls when cultured under multiplication conditions, but when grown under tuber inducing conditions some significant differences were observed: the beta 7 line tuberized earlier than controls without the addition of CCC (GA inhibitor), developed more tubers than wild type plants in the presence of hormones that promote tuberization in potato (ABA and BAP) and was more insensitive to GA action (stolons were significantly shorter than those of control plants). StCDPK1 expression was induced by GA, ABA and BAP. Our results suggest that StCDPK1 plays a role in GA-signalling and that this kinase could be a converging point for the inhibitory and promoting signals that influence the onset of potato tuberization.
Gargantini
Pablo Rubén
PR
Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, CONICET and Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Vuelta de Obligado 2490, piso 2, 1428, Buenos Aires, Argentina.
Giammaria
Verónica
V
Grandellis
Carolina
C
Feingold
Sergio E
SE
Maldonado
Sara
S
Ulloa
Rita María
RM
D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000235:genetics; D005875:Gibberellins / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D035281:Plant Tubers / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D011198:Solanum tuberosum / Q000235:genetics* / Q000378:metabolism
D002135:Calcium-Binding Proteins; D018744:DNA, Plant; D005875:Gibberellins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011494:Protein Kinases