Arabidopsis phosphatase under-producer mutants pup1 and pup3 contain mutations in the AtPAP10 and AtPAP26 genes.

Production and secretion of acid phosphatases (APases) is a hallmark adaptive response of plants to phosphate (Pi) deprivation. Researchers have long hypothesized that Pi starvation-induced APases are involved in internal Pi recycling and remobilization as well as in external Pi utilization. Two phosphatase under-producer (pup) mutants, pup1 and pup3, were previously isolated in Arabidopsis. Characterization of these 2 pup mutants provided the first genetic evidence for the above hypothesis. To date, however, the molecular lesions in these 2 pup mutants remain unknown. In this work, we demonstrate that pup1 and pup3 contain point mutations in the Arabidopsis purple acid phosphatase gene AtPAP10 and AtPAP26, respectively. Our results answer a long-standing question about the molecular identity of the PUP1 and PUP3 genes and corroborate the conclusions from previous studies regarding the function of AtPAP10 and AtPAP26 in plant acclimation to Pi deprivation.