Differential Expression of Arabidopsis thaliana Acid Phosphatases in Response to Abiotic Stresses

The objective of this research is to identify Arabidopsis thaliana genes encoding acid phosphatases induced by phosphate starvation. Multiple alignments of eukaryotic acid phosphatase amino acid sequences led to the classification of these proteins into four groups including purple acid phosphatases (PAPs). Specific primers were degenerated and designed based on conserved sequences of PAPs isolated from plants, fungi and animals. RNA profiles of Pi-fed and Pi-starved A. thaliana roots were compared with two methods established for gene-family-directed differential display of pap genes. Having analyzed the differentially displayed fragments, seven pap encoding cDNA clones were isolated. One of the clones was a trans-splicing product of two genes that encodes an acid phosphatase carrying a zinc-finger domain. Six other clones were predicted to encode secretory phosphatases. Reverse-northern blotting and semi-quantitative RT-PCR revealed distinct expression patterns for each gene under diverse environmental conditions such as Pi starvation, high-salt concentration, cold shock, nitrogen and sulfur deprivation. The presented data can provide some clues for dissecting the possible roles of PAPs in Pi acquisition.