Differential responses of rice acid phosphatase activities and isoforms to phosphorus deprivation.
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.
Lim
Jeong Hyun
JH
Institute for Agricultural Science and Technology, Chonbuk National University, Chonju 561-756, Korea.
Chung
Ill-Min
IM
Ryu
Sang Soo
SS
Park
Myoung Ryoul
MR
Yun
Song Joong
SJ
D000135:Acid Phosphatase / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism*; D012275:Oryza / Q000201:enzymology*; D010758:Phosphorus / Q000008:administration & dosage*; D018517:Plant Roots / Q000201:enzymology
D007527:Isoenzymes; D010758:Phosphorus; D000135:Acid Phosphatase