Abscisic acid suppresses hypocotyl elongation by dephosphorylating plasma membrane H(+)-ATPase in Arabidopsis thaliana.
Plant Cell Physiol
; 55(4): 845-53, 2014 Apr.
Article
em En
| MEDLINE
| ID: mdl-24492258
ABSTRACT
Plasma membrane H(+)-ATPase is thought to mediate hypocotyl elongation, which is induced by the phytohormone auxin through the phosphorylation of the penultimate threonine of H(+)-ATPase. However, regulation of the H(+)-ATPase during hypocotyl elongation by other signals has not been elucidated. Hypocotyl elongation in etiolated seedlings of Arabidopsis thaliana was suppressed by the H(+)-ATPase inhibitors vanadate and erythrosine B, and was significantly reduced in aha2-5, which is a knockout mutant of the major H(+)-ATPase isoform in etiolated seedlings. Application of the phytohormone ABA to etiolated seedlings suppressed hypocotyl elongation within 30 min at the half-inhibitory concentration (4.2 µM), and induced dephosphorylation of the penultimate threonine of H(+)-ATPase without affecting the amount of H(+)-ATPase. Interestingly, an ABA-insensitive mutant, abi1-1, did not show ABA inhibition of hypocotyl elongation or ABA-induced dephosphorylation of H(+)-ATPase. This indicates that ABI1, which is an early ABA signaling component through the ABA receptor PYR/PYL/RCARs (pyrabactin resistance/pyrabactin resistance 1-like/regulatory component of ABA receptor), is involved in these responses. In addition, we found that the fungal toxin fusiccocin (FC), an H(+)-ATPase activator, induced hypocotyl elongation and phosphorylation of the penultimate threonine of H(+)-ATPase, and that FC-induced hypocotyl elongation and phosphorylation of H(+)-ATPase were significantly suppressed by ABA. Taken together, these results indicate that ABA has an antagonistic effect on hypocotyl elongation through, at least in part, dephosphorylation of H(+)-ATPase in etiolated seedlings.
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01-internacional
Base de dados:
MEDLINE
Assunto principal:
Membrana Celular
/
Arabidopsis
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Ácido Abscísico
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Hipocótilo
Idioma:
En
Revista:
Plant Cell Physiol
Ano de publicação:
2014
Tipo de documento:
Article