Molecular cloning and characterization of phosphorus starvation responsive genes in common bean (Phaseolus vulgaris L.)

Abstract

Common bean (Phaseolus vulgaris L.) is one of the most important food legumes in the world and its production is limited by low phosphate (Pi) availability in many arable soils. To gain better insight into the molecular mechanisms by which common bean adapts to low Pi availability, we generated a suppression subtractive cDNA library to identify genes involved in P starvation responses. Over 240 putative Pi starvation-responsive genes were identified. The identified clones were sequenced and BLASTx/BLASTn analysis revealed an array of 82 genes showing a high degree of sequence homology to known and unknown proteins in the database. Transcript abundance of seven genes representing different functional categories was examined by Northern blot analysis. Six genes were strongly induced/enhanced under Pi deficiency confirming the results of SSH. Full length cDNAs for three genes, representing PvIDS4-like, PvPS2, and PvPT1 were cloned and characterized. The open reading frame (ORF) of PvIDS4-like encodes a 281-amino acid protein, containing a SPX domain. The ORF of PvPS2 gene encodes a 271-amino acid protein coding for a putative phosphatase. The PvPT1 encodes a 531-amino acid protein exhibiting high homology with high affinity Pi transporters. Expression patterns of these three genes in relation to Pi availability were evaluated with two contrasting genotypes (P-inefficient Dor364 and P-efficient G19833). Both Northern and RT-PCR results showed enhanced accumulation of phosphate transporters and phosphatases in P-efficient genotype, implying that in addition to modified root morphology and architecture, increased P transport and phosphatases activity might contribute to efficient Pi acquisition and translocation in G19833 common bean genotype under limited Pi conditions.

Genomics of Origin, Domestication and Evolution of Phaseolus vulgaris

“…They finally identified 3,126 unigenes, and of these only 314 showed similarity to sequences from the existing database. Tian et al (2007) constructed a suppression subtractive cDNA library to identify genes involved in response to phosphorous starvation. They characterized the differentially expressed genes into five functional groups, and by comparison with the GenBank non-redundant database, they were able to further classify 72 genes.…”

Sugar Signaling in Root Responses to Low Phosphorus Availability

“…Increased expression of AtSPX3 occurs upon prolonged P starvation and appears to act in feedback regulation of plant responses to P starvation by down-regulating the expression of AtSPX1, At4, and genes encoding several Pi transporters, RNases, and phosphatases (Duan et al, 2008). Functional homologs of these genes have been identified in bean (Phaseolus vulgaris; Tian et al, 2007) and rice (Wang et al, 2009a(Wang et al, , 2009bLiu et al, 2010a). In rice, OsSPX1 is induced by low P availability in the roots and acts downstream of OsPHR2 (Wang et al, 2009a).…”

Molecular cloning and characterization of phosphate (Pi) responsive genes in Gulf ryegrass (Lolium multiflorum L.): a Pi hyperaccumulator

“…However, limitations of global gene expression analysis due to the lack of entire genomic sequence information or microarrays for many of the model and crop species could be circumvented by suppression subtractive hybridization (SSH) technique. Differentially expressed genes could be normalized and enriched over 1,000-fold in a single round of hybridization by SSH and has been used successfully for identification of various biotic and abiotic stress responsive genes (Diatchenko et al 1999;Zhang et al 2005;Tian et al 2007;Venkatachalam et al 2007). …”