Functional Interconnection of MYC2 and SPA1 in the Photomorphogenic Seedling Development of Arabidopsis

Gangappa, Sreeramaiah N.; Prasad, Vivek; Chattopadhyay, Sudip

doi:10.1104/pp.110.163717

Cited by 62 publications

(82 citation statements)

References 38 publications

(58 reference statements)

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“…6B). This observation agrees with prior results for jar1 (Staswick et al, 1992(Staswick et al, , 2002Lorenzo et al, 2004) and myc2 (Lorenzo et al, 2004;Yadav et al, 2005;Gangappa et al, 2010).…”

Section: Root-localized Pfb or Phytochromes Impact The Arabidopsis Rosupporting

confidence: 93%

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Root-Localized Phytochrome Chromophore Synthesis Is Required for Photoregulation of Root Elongation and Impacts Root Sensitivity to Jasmonic Acid in Arabidopsis

et al. 2011

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Plants exhibit organ-and tissue-specific light responses. To explore the molecular basis of spatial-specific phytochromeregulated responses, a transgenic approach for regulating the synthesis and accumulation of the phytochrome chromophore phytochromobilin (PFB) was employed. In prior experiments, transgenic expression of the BILIVERDIN REDUCTASE (BVR) gene was used to metabolically inactivate biliverdin IXa, a key precursor in the biosynthesis of PFB, and thereby render cells accumulating BVR phytochrome deficient. Here, we report analyses of transgenic Arabidopsis (Arabidopsis thaliana) lines with distinct patterns of BVR accumulation dependent upon constitutive or tissue-specific, promoter-driven BVR expression that have resulted in insights on a correlation between root-localized BVR accumulation and photoregulation of root elongation. Plants with BVR accumulation in roots and a PFB-deficient elongated hypocotyl2 (hy2-1) mutant exhibit roots that are longer than those of wild-type plants under white illumination. Additional analyses of a line with root-specific BVR accumulation generated using a GAL4-dependent bipartite enhancer-trap system confirmed that PFB or phytochromes localized in roots directly impact light-dependent root elongation under white, blue, and red illumination. Additionally, roots of plants with constitutive plastid-localized or root-specific cytosolic BVR accumulation, as well as phytochrome chromophore-deficient hy1-1 and hy2-1 mutants, exhibit reduced sensitivity to the plant hormone jasmonic acid (JA) in JA-dependent root inhibition assays, similar to the response observed for the JA-insensitive mutants jar1 and myc2. Our analyses of lines with root-localized phytochrome deficiency or root-specific phytochrome depletion have provided novel insights into the roles of root-specific PFB, or phytochromes themselves, in the photoregulation of root development and root sensitivity to JA.

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Section: Root-localized Pfb or Phytochromes Impact The Arabidopsis Rosupporting

confidence: 93%

“…The jar1 and myc2 mutants showed reduced expression of VSP1 independent of MeJA treatment (Fig. 7), which has been noted previously for jar1 (Tuominen et al, 2004;Gangappa et al, 2010).…”

Section: Root-localized Pfb or Phytochromes Impact The Arabidopsis Rosupporting

confidence: 86%

Root-Localized Phytochrome Chromophore Synthesis Is Required for Photoregulation of Root Elongation and Impacts Root Sensitivity to Jasmonic Acid in Arabidopsis

et al. 2011

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“…Moreover, members of the SPA protein family (SPA1-SPA4), which are DWD proteins like COP1, can physically interact with COP1 and, together, they constitute functional E3-ubiquitin ligase complexes (Zhu et al, 2008;Chen et al, 2010). MYC2 has been functionally related to SPA1; both proteins act redundantly or synergistically in the regulation of photomorphogenic responses, which opens the possibility that SPA proteins might be required for interaction between COP1 and MYC2 in vivo (Gangappa et al, 2010). Therefore, elucidation of the mechanism of MYCs regulation by COP1 may be complex and will require further research.…”

Section: Discussionmentioning

confidence: 99%

Repression of Jasmonate-Dependent Defenses by Shade Involves Differential Regulation of Protein Stability of MYC Transcription Factors and Their JAZ Repressors in Arabidopsis

et al. 2014

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Reduction of the red/far-red (R/FR) light ratio that occurs in dense canopies promotes plant growth to outcompete neighbors but has a repressive effect on jasmonate (JA)-dependent defenses. The molecular mechanism underlying this trade-off is not well understood. We found that the JA-related transcription factors MYC2, MYC3, and MYC4 are short-lived proteins degraded by the proteasome, and stabilized by JA and light, in Arabidopsis thaliana. Dark and CONSTITUTIVE PHOTOMORPHOGENIC1 destabilize MYC2, MYC3, and MYC4, whereas R and blue (B) lights stabilize them through the activation of the corresponding photoreceptors. Consistently, phytochrome B inactivation by monochromatic FR light or shade (FR-enriched light) destabilizes these three proteins and reduces their stabilization by JA. In contrast to MYCs, simulated shade conditions stabilize seven of their 10 JAZ repressors tested and reduce their degradation by JA. MYC2, MYC3, and MYC4 are required for JA-mediated defenses against the necrotrophic pathogen Botrytis cinerea and for the shade-triggered increased susceptibility, indicating that this negative effect of shade on defense is likely mediated by shade-triggered inactivation of MYC2, MYC3, and MYC4. The opposite regulation of protein stability of MYCs and JAZs by FR-enriched light help explain (on the molecular level) the long-standing observation that canopy shade represses JA-mediated defenses, facilitating reallocation of resources from defense to growth.

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“…Other bZIP transcription factors, GBF2, GBF3, and HY5, and bHLH transcription factors MYC2, PIL5, PIF3, PIF4, PIF7, and CRYPTOCHROME-INTERACTING BASIC-HELIX-LOOP-HELIX1 could also bind with G-box to regulate light-mediated gene expression and physiological responses (Schindler et al, 1992a;Chattopadhyay et al, 1998;Martínez-García et al, 2000;Huq and Quail, 2002;Yadav et al, 2005;Liu et al, 2008;Moon et al, 2008;Kidokoro et al, 2009;Oh et al, 2009;Gangappa et al, 2010). Previous study indicated that GBF1, GBF2, and GBF3 could heterodimerize with each other, and the heterodimers could bind with the G-box (Schindler et al, 1992a).…”

Section: Functions Of G-box Binding Proteinsmentioning

confidence: 99%

Arabidopsis bZIP16 Transcription Factor Integrates Light and Hormone Signaling Pathways to Regulate Early Seedling Development

Hsieh

2012

Plant Cell

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Functional Interconnection of MYC2 and SPA1 in the Photomorphogenic Seedling Development of Arabidopsis

Cited by 62 publications

References 38 publications

Root-Localized Phytochrome Chromophore Synthesis Is Required for Photoregulation of Root Elongation and Impacts Root Sensitivity to Jasmonic Acid in Arabidopsis

Root-Localized Phytochrome Chromophore Synthesis Is Required for Photoregulation of Root Elongation and Impacts Root Sensitivity to Jasmonic Acid in Arabidopsis

Repression of Jasmonate-Dependent Defenses by Shade Involves Differential Regulation of Protein Stability of MYC Transcription Factors and Their JAZ Repressors in Arabidopsis

Arabidopsis bZIP16 Transcription Factor Integrates Light and Hormone Signaling Pathways to Regulate Early Seedling Development

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