Functional Studies of the Effects of FIN219 and COI1 Interaction on Far-Red Light and Jasmonic Acid Signaling in Arabidopsis thaliana
Date Issued
2012
Date
2012
Author(s)
Chen, Yu-An
Abstract
In Arabidopsis, FAR-RED INSENSIVIVE 219 (FIN219)/JASMONATE RESISTANT 1 (JAR1) and CORONATINE INSENSITIVE 1 (COI1) are positive regulators in jasmonate (JA) signaling. FIN219/JAR1 catalyzes the synthesis of JA-isoleucine (JA-Ile), which is a bioactive conjugate of JA that promotes the binding of SFCCOI1 and JASMONATE-ZIM-DOMAIN PROTEINs (JAZs). This binding results in the degradation of JA signaling repressors JAZs by 26S proteasome. Recent publications indicate that both FIN219 and COI1 are involved in phytochrome A mediated high irradiance response during seedling de-etiolation. This study aimed to elucidate the relation of FIN219 and COI1 in FR light and JA signaling. We found that FIN219 and COI1 synergistically regulate fertility and FR light sensitivity. However, COI1 overexpression may suppress the effect of FIN219 overexpression on hypocotyl growth by post-transcriptional regulation. The results of pull-down and yeast two-hybrid assays suggest that FIN219 and COI1 may interact. We also showed both proteins can co-localize in the nuclei of Arabidopsis protoplasts. By generating FLAG-COI1 overexpression plants, we showed that JA perception/signaling promotes COI1 accumulation, whereas FIN219 represses this phenomenon. In FR light, COI1 overexpression suppressed fin219-2 long-hypocotyl phenotype. Both FIN219 and COI1 contribute to HY5 accumulation upon JA activation in FR light, which FIN219 and COI1 may exert their function synergistically. Taken together, the regulatory relationship of FIN219 and COI1 is fine-tuningly modulated and has a crosstalk between FR light and JA signalings.
Subjects
Arabidopsis
photomorphogenesis
jasmonate
far-red light
interaction
Type
thesis
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