Expression pattern and subcellular localization of Arabidopsis purple acid phosphatase AtPAP9

•Analyzing T-DNA lines, the existence of two mRNA variants for AtPAP9 were shown.•AtPAP9 was mainly expressed in stipule and vascular tissue in response to fungal infection.•AtPAP9 could be involved in plasma membrane and cell wall adhesion, playing a signaling role.•The variants differ for the N-terminal, producing both HMW and LMW phosphatases.•A potential role in plasma membrane and cell wall adhesion for PAP9 protein is conceivable.

Purple acid phosphatase (PAP; EC 3.1.3.2) enzymes are metallophosphoesterases that hydrolysis phosphate ester bonds in a wide range of substrates. Twenty-nine PAP-encoding loci have been identified in the Arabidopsis genome, many of which have multiple transcript variants expressed in response to diverse environmental conditions. Having analyzed T-DNA insertion mutants, we have provided strong pieces of evidence that AtPAP9 locus encodes at least two types of transcripts, designated as AtPAP9-1 and AtPAP9-2. These transcript variants expressed distinctly during the course of growth in medium containing sufficient phosphate or none. Further histochemical analysis by the use of AtPAP9-1 promoter fused to β-glucuronidase reporter gene indicated the expression of this gene is regulated in a tissue-specific manner. AtPAP9-1 was highly expressed in stipule and vascular tissue, particularly in response to fungal infection. Subcellular localization of AtPAP9-1:green fluorescent fusion protein showed that it must be involved in plasma membrane and cell wall adhesion.

Graphical abstractAtPAP9 locus encodes at least two types of transcripts, designated as AtPAP9-1 and AtPAP9-2. These transcript variants expressed distinctly during the course of growth in medium containing sufficient or no phosphate.Figure optionsDownload full-size imageDownload high-quality image (66 K)Download as PowerPoint slide