title: Differential responses of rice acid phosphatase activities and isoforms to phosphorus deprivation.
abstract: Acid phosphatases (APases) play a role in the release of phosphate in organic complexes in soil. We investigated tissue- and isoform-specific responses of APases to phosphorus (P) deficiency in three rice genotypes; Dasan-byeo, Sobi-byeo, and Palawan. The levels of shoot APase activity per protein were similar in the three genotypes. They significantly decreased with P deprivation that was longer than seven days. Root APase activity per protein was two- to three-fold higher in Dasan than in Sobi and Palawan. In all genotypes the APase activity increased in P-deficient plants, but the increase was higher in Sobi and Palawan. After 21 days of P deprivation, secreted APase activity increased more than eight-fold in Dasan and two-fold in Sobi and Palawan. Isoform profiles of shoot and root APases were most diverse in Dasan. The activities of the major isoforms in P-deficient shoots decreased in all three genotypes. Depending on the genotypes, further increases in constitutive isoforms and new induction of one to four isoforms occurred in P-deficient roots. The results indicate that tissue and genotype differences in the response of APase to P deficiency are primarily facilitated by the different responses of the isoforms.
authors.affiliation: Institute for Agricultural Science and Technology, Chonbuk National University, Chonju 561-756, Korea.
authors.forename: Jeong Hyun
authors.initials: JH
authors.lastname: Lim
authors.forename: Ill-Min
authors.initials: IM
authors.lastname: Chung
authors.forename: Sang Soo
authors.initials: SS
authors.lastname: Ryu
authors.forename: Myoung Ryoul
authors.initials: MR
authors.lastname: Park
authors.forename: Song Joong
authors.initials: SJ
authors.lastname: Yun
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism*; D012275:Oryza / Q000201:enzymology*; D010758:Phosphorus / Q000008:administration & dosage*; D018517:Plant Roots / Q000201:enzymology
chemical_list: D007527:Isoenzymes; D010758:Phosphorus; D000135:Acid Phosphatase