Functional Studies of HY5 in Light and Jasmonic Acid Signaling in Arabidopsis
Date Issued
2012
Date
2012
Author(s)
Liao, Li-Lin
Abstract
Light crosstalks with different hormones to modulate plant development. LONG HYPOCOTYL5 (HY5), a bZIP transcription factor, acts downstream of light signal transduction and promotes photomorphogenesis in Arabidopsis. Recent studies indicate that HY5 is the integrator of light and multiple hormones such as auxin, gibberellins and abscisic acid. However, there is no evidence showing HY5 involvement in jasmonic acid (JA) signaling. Our previous data showed that HY5 protein level is induced by methyl jasmonate and coronatine that is a phytotoxin and mimics the structure of JA-isoleucine (JA-Ile), an active form of JA. HY5 induction by MeJA substantially reduced in fin219-2.Moreover, our data revealed that HY5 might interact with JAZ proteins in yeast two-hybrid studies. Besides, inhibition of hypocotyl and root elongation, as well as anthocyanin accumulation has been used as indicators of JA-mediated physiological responses. Thus, our data further showed that hy5 mutant lines exhibited insensitive responses to exogenous MeJA treatments. This result implies that HY5 may be a positive regulator in JA signaling pathway. In addition, our microarray data showed that many genes, including JAZ, CHS and MYBs involved in various hormone signaling pathways were up- or down-regulated in hy5 mutant lines with MeJA treatment. Thus, HY5 may participate in JA signaling pathway to regulate JA-mediated anthocyanin accumulation.
Subjects
HY5
light
jasmonic acid
arabidopsis
Type
thesis
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