Studies of the Molecular Mechanisms Underlying Arabidopsis FIN219 and Cryptochromes Regulated Ethylene Responses
Date Issued
2009
Date
2009
Author(s)
Hsieh, Chen-Chui
Abstract
Ethylene, a gaseous phytohormone, participates in the regulation of plant development and defense responses. Dark-grown Arabidopsis seedlings under ethylene treatment exhibit triple response phenotype, including exaggerated apical hooks, shortened and thickened hypocotyls, and shortened roots. Previous studies indicated that FIN219 and cryptochromes may regulate ethylene responses. However, the molecular mechanisms underlying their involvement in ethylene signaling remain unknown. Here, we found that fin219, cry1, 35S::GUS-CCT1, and cry1 cry2 were hypersensitive to ACC, but the cry2 mutant showed a sensitivity similar to that in wild-type Columbia (Col). This result indicates that FIN219 and CRY1 negatively regulate ethylene responses, which is consistent with the fact that several ethylene biosynthetic genes. In addition, signaling related genes are also increased in both fin219 and cry1 mutants. Moreover, the cry1 fin219 double mutant and the cry1 cry2 fin219 triple mutant exhibited ACC sensitivities similar to Col. Intriguingly, FIN219 overexpression in cry1 mutant resulted in a hypersensitive response to ACC, but in cry1 cry2 double mutant did not, which implies that FIN219 may negatively regulate ethylene responses with a requirement of the functional CRY2. In addition, MeJA application can partially rescue the hypersensitive responses of the fin219 mutant to ACC, and the coronatine, a JA-Ile analog can fully rescue the defect in ACC responses of the fin219 mutant. Taken together, these data indicate that FIN219 negatively regulates ethylene responses through JA signaling.
Subjects
ethylene
cryptochrome
triple response
jasmonate
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