Plant Physiol, April 2001, Vol. 125, pp. 1901-1911
Induction of a Major Leaf Acid Phosphatase Does Not Confer
Adaptation to Low Phosphorus Availability in Common
Bean1
Xiaolong
Yan,
Hong
Liao,
Melanie C.
Trull,
Steve E.
Beebe, and
Jonathan P.
Lynch*
Laboratory of Plant Nutritional Genetics, South China Agricultural
University, Guangzhou 510642, China (X.Y., H.L.); Department of
Horticulture, Pennsylvania State University, University Park,
Pennsylvania 16802 (H.L., M.C.T., J.P.L.); and International Center for
Tropical Agriculture, Apartado Aereo 6713, Cali, Colombia
(S.E.B.)
Acid phosphatase is believed to be important for
phosphorus scavenging and remobilization in plants, but its role in
plant adaptation to low phosphorus availability has not been critically evaluated. To address this issue, we compared acid phosphatase activity
(APA) in leaves of common bean (Phaseolus vulgaris) in a
phosphorus-inefficient genotype (DOR364), a phosphorus-efficient genotype (G19833), and their F5.10 recombinant inbred lines (RILs). Phosphorus deficiency substantially increased leaf APA, but APA
was much higher and more responsive to phosphorus availability in
DOR364 than in G19833. Leaf APA segregated in the RILs, with two
discrete groups having either high (mean = 1.71 µmol/mg protein/min) or low (0.36 µmol/mg protein/min) activity. A chi-square test indicated that the observed difference might be controlled by a
single gene. Non-denaturing protein electrophoresis revealed that there
are four visible isoforms responsible for total APA in common bean, and
that the difference in APA between contrasting genotypes could be
attributed to the existence of a single major isoform. Qualitative
mapping of the APA trait and quantitative trait loci analysis with
molecular markers indicated that a major gene contributing to APA is
located on linkage group B03 of the unified common bean map. This
locus was not associated with loci conferring phosphorus
acquisition efficiency or phosphorus use efficiency. RILs contrasting
for APA had similar phosphorus pools in old and young leaves under
phosphorus stress, arguing against a role for APA in phosphorus
remobilization. Our results do not support a major role for leaf APA
induction in regulating plant adaptation to phosphorus deficiency.
1
This research was supported by the U.S.
Department of Agriculture/National Research Initiative (grant
nos. 97-35100-4456 and 99-00632 to J.P.L.), by the National Key
Basic Research Special Funds of China (grant no. G1999011700 to X.Y.),
and by the National Natural Science Foundation (grant no. 39925025 to
X.Y.).
*
Corresponding author; email JPL4{at}psu.edu; fax
814-863-6139.
© 2001 American Society of Plant Physiologists
