Root plasma membrane H+-ATPase is involved in the adaptation of soybean to phosphorus starvation.
The plasma membrane H+-ATPase plays an important role in the plant response to nutrient and environmental stresses. However, the involvement of plant root plasma membrane H+-ATPase in adaptation to phosphate (P) starvation is not yet fully elucidated. In this study, experiments were performed with soybean roots in low-P nutrient solution (10 microM). Treatment with fusicoccin, an activator of the plasma membrane H+-ATPase, increased P uptake by 35%, while vanadate, an inhibitor of plasma membrane H+-ATPase, severely suppressed it. These results suggested that P uptake might be regulated via the modulation of the activity of plasma membrane H+-ATPase under P starvation. The relationship between P uptake and the activity of plasma membrane H+-ATPase was examined further by using plasma membrane H+-ATPase transgenic Arabidopsis thaliana under low-P conditions. Transgenic plants absorbed more P compared with wild-type Arabidopsis. Results from real-time RT-PCR, western-blotting and immunolocalization analysis indicated that the increase in activity of the plasma membrane H+-ATPase by P starvation was caused by its transcriptional and translational regulation. A higher expression was observed at the translational level than at the transcriptional level. P starvation could induce a transient increase of endogenous indole-3-acetic acid (IAA) in soybean roots. The exogenous application of IAA stimulated the activity of plasma membrane H+-ATPase and P uptake, while naphthylphthalamic acid (NPA), an IAA transport inhibitor, blocked IAA effects. Taken together, these results suggested an involvement of root plasma membrane H+-ATPase in the adaptation of soybean to P starvation. IAA might be involved in signal transduction of P starvation by activating the plasma membrane H+-ATPase in soybean roots.
Laboratory of Plant Nutritional Genetics and Root Biology Center, College of Resources and Environment, South China Agricultural University, Guangzhou 510642, PR China.
Hong
H
Shen
Jianhong
J
Chen
Zhanyi
Z
Wang
Cunyi
C
Yang
Takara
T
Sasaki
Yoko
Y
Yamamoto
Hideaki
H
Matsumoto
Xiaolong
X
Yan
D000222:Adaptation, Physiological; D002462:Cell Membrane / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D007210:Indoleacetic Acids / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism*; D018517:Plant Roots / Q000201:enzymology / Q000502:physiology*; D030821:Plants, Genetically Modified; D006180:Proton-Translocating ATPases / Q000378:metabolism; D015398:Signal Transduction; D013025:Glycine max / Q000201:enzymology / Q000235:genetics / Q000502:physiology*
D007210:Indoleacetic Acids; D010758:Phosphorus; D006180:Proton-Translocating ATPases