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Characterization of a type A response regulator in the common bean ( Phaseolus vulgaris ) in response to phosphate starvation
Author(s) -
Camacho Yolanda,
MartínezCastilla León,
Fragoso Selene,
Vázquez Sonia,
MartínezBarajas Eleazar,
Coello Patricia
Publication year - 2008
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2007.01005.x
Subject(s) - phaseolus , starvation response , biology , arabidopsis thaliana , rgs2 , cytokinin , phosphate , response regulator , arabidopsis , biochemistry , signal transduction , complementary dna , mutant , microbiology and biotechnology , gene , botany , auxin , g protein , gtpase activating protein
Type A response regulators are a family of genes in Arabidopsis thaliana involved primarily in cytokinin signal transduction. A member of this family was isolated from a cDNA library constructed from bean plants ( Phaseolus vulgaris ) grown under conditions of phosphate starvation. The complete cDNA sequence showed the presence of the DDK domain, which is the hallmark of the response regulator family. Expression of the P. vulgaris response regulator 1 ( PvRR1 ) showed clear regulation based on phosphate availability because transcript levels increased during phosphate starvation and returned to basal levels after resupplementation with phosphorus. Nitrogen and potassium starvation also upregulated PvRR1 , indicating that cross talk with other nutrient signaling pathways might occur. Addition of cytokinins to plants growing under phosphate‐sufficient conditions stimulated PvRR1 transcript levels both in detached leaves and in roots. However, cytokinins strongly inhibited PvRR1 expression in phosphate‐starved plants after 24 h of incubation. At the protein level, subcellular localization of PvRR1 indicated that it is a nuclear protein and that phosphate starvation modified protein levels but not the localization.