title: Expression of the rice CDPK-7 in sorghum: molecular and phenotypic analyses.
abstract: Sorghum (Sorghum bicolor (L.) Moench) is an important source for food, feed, and possesses many agronomic attributes attractive for a biofuels feedstock. A warm season crop originating from the semi-arid tropics, sorghum is relatively susceptible to both cold and freezing stress. Enhancing the ability of sorghum to tolerate cold and freezing offers a route to expand the acreage for production, and provides a potential drought avoidance strategy during flowering, an important parameter for protection of yield. Targeted perturbation of the signal transduction pathway, that is triggered by exposure to abiotic stress in plants, has been demonstrated in model systems as an avenue to augment tolerance. Calcium-dependent protein kinases (CDPKs) are key players in a plant's response to environmental assaults. To test the impact of modulating CDPK activity in sorghum as a means to enhanced abiotic stress tolerance, we introduced a constitutively expressed rice CDPK-7 (OsCDPK-7) gene construct. Sorghum transformants carrying this cassette, were not improved in cold or salt stress under the conditions tested. However, a lesion mimic phenotype and up-regulation of a number of pathogen related proteins, along with transcripts linked to photosynthesis were observed. These results demonstrate that modulating the Ca signaling cascade in planta via unregulated enhanced CDPK activity can lead to off-type effects likely due to the broadly integrated nature of these enzymes in signaling.
authors.affiliation: Department of Agronomy & Horticulture, University of Nebraska-Lincoln, Lincoln, NE 68583, USA.
authors.forename: Tejinder Kumar
authors.initials: TK
authors.lastname: Mall
authors.forename: Ismail
authors.initials: I
authors.lastname: Dweikat
authors.forename: Shirley J
authors.initials: SJ
authors.lastname: Sato
authors.forename: Natalya
authors.initials: N
authors.lastname: Neresian
authors.forename: Kaimei
authors.initials: K
authors.lastname: Xu
authors.forename: Zhengxiang
authors.initials: Z
authors.lastname: Ge
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Thomas
authors.initials: T
authors.lastname: Elthon
authors.forename: Tom
authors.initials: T
authors.lastname: Clemente
mesh_terms: D000064:Acclimatization / Q000235:genetics / Q000502:physiology; D000595:Amino Acid Sequence; D001483:Base Sequence; D020013:Calcium Signaling; D003081:Cold Climate; D018744:DNA, Plant / Q000235:genetics; D015870:Gene Expression; D017343:Genes, Plant; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology* / Q000235:genetics*; D010641:Phenotype; D030821:Plants, Genetically Modified; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D045868:Sorghum / Q000201:enzymology* / Q000235:genetics*; D013312:Stress, Physiological; D014170:Transformation, Genetic; D017871:Calcium-Calmodulin-Dependent Protein Kinases
chemical_list: D018744:DNA, Plant; D011494:Protein Kinases; D011994:Recombinant Proteins; C454865:calcium-dependent protein kinase, rice; D017871:Calcium-Calmodulin-Dependent Protein Kinases