作者: Mohammed Ali Malboobi , Daniel D. Lefebvre
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摘要: We have previously isolated a phosphate starvation-response (psr) cDNA clone, psr3.1, from Brassica nigra which encodes β-glucosidase. Southern blots of Arabidopsis thaliana genomic DNA probed with the psr3.1 indicated that this gene exists as single locus. A library A. was screened at high stringency to isolate corresponding clone. The resultant clone coined psr3.2 because its sequence divergence clones. Northern blotting probes derived coding region showed is expressed levels in Pi-starved roots and enhancement occurred within two days growth medium lacking Pi. expression repressed by heat shock anaerobic conditions, it not significantly induced salinity, or nitrogen sulfur deprivation. Sequence analysis revealed existence 13 exons interrupted 12 AT-rich introns possessed homology B. well various other β-glucosidase genes species. similarity percentages between deduced amino acid sequences psr3 clones β-glycosidases suggests they should be included along Brassicaceae distinct subfamily BGA glycosidase family. presence an endoplasmic reticulum retention signal carboxy terminus indicates likely cellular location PSR3.2. possible metabolic regulatory roles enzyme during Pi-starvation response are discussed.