Trichomes that cover the epidermis of aerial plant organs play multiple roles in plant protection.Compared with a unicellular trichome in model plants,the development mechanism of the multicellular trichome is largely...Trichomes that cover the epidermis of aerial plant organs play multiple roles in plant protection.Compared with a unicellular trichome in model plants,the development mechanism of the multicellular trichome is largely unclear.Notably,variations in trichome development are often accompanied by defects in the biosynthesis of cuticle and secondary metabolites;however,major questions about the interactions between developmental differences in trichomes and defects in metabolic pathways remain unanswered.Here,we characterized the glabrous mutant mict/csgl1/cstbh via combined metabolomic and transcriptomic analyses to extend our limited knowledge regarding multicellular trichome development and metabolism in cucumber.Mict was found to be explicitly expressed within trichome cells.Transcriptomic analysis indicated that genes involved in flavonoid and cuticle metabolism are significantly downregulated in mict mutants.Further metabolomic analysis confirmed that flavonoids,lipids,and cuticle compositions are dramatically altered in mict mutants.Additional studies revealed that Mict regulates flavonoid,lipid,and cuticle biosynthesis by likely directly binding to downstream functional genes,such as CsTT4,CsFLS1,CsCER26,and CsMYB36.These findings suggest that specific metabolic pathways(e.g.,flavonoids and cuticle components)are co-regulated by Mict and provide insights into transcriptional regulation mechanisms of multicellular trichome development and its specific metabolism in cucumber.展开更多
Light is a key environmental cue that inhibits hypocotyl cell elongation through the blue and red/far-red light photoreceptors cryptochrome- and phytochrome-mediated pathways in Arabidopsis. In contrast, as a pivotal ...Light is a key environmental cue that inhibits hypocotyl cell elongation through the blue and red/far-red light photoreceptors cryptochrome- and phytochrome-mediated pathways in Arabidopsis. In contrast, as a pivotal endogenous phytohormone auxin promotes hypocotyl elongation through the auxin receptors TIR1/AFBs-mediated degradation of AUX/IAA proteins （AUX/IAAs）. However, the molecular mechanisms underlying the antagonistic interaction of light and auxin signaling remain unclear. Here, we report that light inhibits auxin signaling through stabilization of AUX/IAAs byblue and red light-dependent interactions of cryptochrome 1 （CRY1） and phytochrome B with AUX/IAAs, respectively. Blue light-triggered interactions of CRY1 with AUX/IAAs inhibit the associations of TIR1 with AUX/IAAs, leading to the repression of auxin- induced degradation of these proteins. Our results indicate that photoreceptors share AUX/IAAs with auxin receptors as the same direct downstream signaling components. We propose that antagonistic regulation of AUX/IAA protein stability by photoreceptors and auxin receptors allows plants to balance light and auxin signals to optimize their growth.展开更多
Light and the heterotrimeric G-protein are known to antagonistically regulate photomorphogenesis in Arabidopsis. However, whether light and G-protein coordinate the regulation of photomorphogenesis is largely unknown....Light and the heterotrimeric G-protein are known to antagonistically regulate photomorphogenesis in Arabidopsis. However, whether light and G-protein coordinate the regulation of photomorphogenesis is largely unknown. Here we show that the blue light photoreceptor cryptochrome 1 （CRY1） physically inter-acts with the G-protein β subunit, AGB1, in a blue light-dependent manner. We also show that AGB1 directly interacts with HY5, a basic leucine zipper transcriptional factor that acts as a critical positive regulator of photomorphogenesis, to inhibit its DNA-binding activity. Genetic studies suggest that CRY1 acts partially through AGB1, and AGB1 acts partially through HY5 to regulate photomorphogenesis. Moreover, we demonstrate that blue light-triggered interaction of CRY1 with AGB1 promotes the dissociation of HY5 from AGB1. Our results suggest that the CRY1 signaling mechanism involves positive regulation of the DNA-binding activity of HY5 mediated by the CRY1-AGB1 interaction, which inhibits the association of AGB1 with HY5. We propose that the antagonistic regulation of HY5 DNA-binding activity by CRY1 and AGB1 may allow plants to balance light and G-protein signaling and optimize photomorphogenesis.展开更多
Phytochrome B (phyB), the primary red light photoreceptor, promotes photomorphogenesis in Arabidopsis by interacting with the basic helix-loop-helix transcriptional factor PIF3 and inducing its phosphorylation and deg...Phytochrome B (phyB), the primary red light photoreceptor, promotes photomorphogenesis in Arabidopsis by interacting with the basic helix-loop-helix transcriptional factor PIF3 and inducing its phosphorylation and degradation. Heterotrimeric G proteins are known to regulate various developmental processes in plants and animals. In Arabidopsis, the G-protein β subunit AGB1 is known to repress photomorphogenesis. However, whether and how phyB and AGB1 coordinately regulate photomorphogenesis are largely unknown. Here we show that phyB physically interacts with AGB1 in a red light-dependent manner and that AGB1 interacts directly with PIF3. Moreover, we demonstrate that the AGB1-PIF3 interaction inhibits the association of PIF3 with phyB, leading to reduced phosphorylation and degradation of PIF3, whereas the phyB-AGB1 interaction represses the association of PIF3 with AGB1, resulting in enhaneed phosphorylation and degradation of PIF3. Our results suggest that phyB and AGB1 antagonistically regulate PIF3 stability by dynamically interacting with each other and PIF3. This dynamic mechanism may allow plants to balanee phyB and G-protein signaling to optimize photomorphogenesis.展开更多
基金the National Key R&D Program of China(Grant No.2018YFD0100701)the National Natural Science Foundation of China(31471156)+1 种基金the Shanghai Agriculture Applied Technology Development Program of China(G2015060402)Shanghai Jiao Tong University“Life Science”Interdisciplinary Research of China(20ZD-02).
文摘Trichomes that cover the epidermis of aerial plant organs play multiple roles in plant protection.Compared with a unicellular trichome in model plants,the development mechanism of the multicellular trichome is largely unclear.Notably,variations in trichome development are often accompanied by defects in the biosynthesis of cuticle and secondary metabolites;however,major questions about the interactions between developmental differences in trichomes and defects in metabolic pathways remain unanswered.Here,we characterized the glabrous mutant mict/csgl1/cstbh via combined metabolomic and transcriptomic analyses to extend our limited knowledge regarding multicellular trichome development and metabolism in cucumber.Mict was found to be explicitly expressed within trichome cells.Transcriptomic analysis indicated that genes involved in flavonoid and cuticle metabolism are significantly downregulated in mict mutants.Further metabolomic analysis confirmed that flavonoids,lipids,and cuticle compositions are dramatically altered in mict mutants.Additional studies revealed that Mict regulates flavonoid,lipid,and cuticle biosynthesis by likely directly binding to downstream functional genes,such as CsTT4,CsFLS1,CsCER26,and CsMYB36.These findings suggest that specific metabolic pathways(e.g.,flavonoids and cuticle components)are co-regulated by Mict and provide insights into transcriptional regulation mechanisms of multicellular trichome development and its specific metabolism in cucumber.
文摘Light is a key environmental cue that inhibits hypocotyl cell elongation through the blue and red/far-red light photoreceptors cryptochrome- and phytochrome-mediated pathways in Arabidopsis. In contrast, as a pivotal endogenous phytohormone auxin promotes hypocotyl elongation through the auxin receptors TIR1/AFBs-mediated degradation of AUX/IAA proteins （AUX/IAAs）. However, the molecular mechanisms underlying the antagonistic interaction of light and auxin signaling remain unclear. Here, we report that light inhibits auxin signaling through stabilization of AUX/IAAs byblue and red light-dependent interactions of cryptochrome 1 （CRY1） and phytochrome B with AUX/IAAs, respectively. Blue light-triggered interactions of CRY1 with AUX/IAAs inhibit the associations of TIR1 with AUX/IAAs, leading to the repression of auxin- induced degradation of these proteins. Our results indicate that photoreceptors share AUX/IAAs with auxin receptors as the same direct downstream signaling components. We propose that antagonistic regulation of AUX/IAA protein stability by photoreceptors and auxin receptors allows plants to balance light and auxin signals to optimize their growth.
基金This work was supported by The National Natural Science Foundation of China grants to H.-Q.Y. （31530085, 91217307, and 90917014） and to H.L. Lian （31570282 and 31170266）, and the National Key Research and Devel- opment Program of China grant （2017YFA0503800）.
文摘Light and the heterotrimeric G-protein are known to antagonistically regulate photomorphogenesis in Arabidopsis. However, whether light and G-protein coordinate the regulation of photomorphogenesis is largely unknown. Here we show that the blue light photoreceptor cryptochrome 1 （CRY1） physically inter-acts with the G-protein β subunit, AGB1, in a blue light-dependent manner. We also show that AGB1 directly interacts with HY5, a basic leucine zipper transcriptional factor that acts as a critical positive regulator of photomorphogenesis, to inhibit its DNA-binding activity. Genetic studies suggest that CRY1 acts partially through AGB1, and AGB1 acts partially through HY5 to regulate photomorphogenesis. Moreover, we demonstrate that blue light-triggered interaction of CRY1 with AGB1 promotes the dissociation of HY5 from AGB1. Our results suggest that the CRY1 signaling mechanism involves positive regulation of the DNA-binding activity of HY5 mediated by the CRY1-AGB1 interaction, which inhibits the association of AGB1 with HY5. We propose that the antagonistic regulation of HY5 DNA-binding activity by CRY1 and AGB1 may allow plants to balance light and G-protein signaling and optimize photomorphogenesis.
基金The National Natural Science Foundation of China grants to H.-Q.Y.(31530085) and H.L.L (31570282 and 31170266)The National Key Research and Development Program of China grant (2017YFA0503802)the Science and Technology Commission of Shanghai Municipality grant (18DZ2260500).
文摘Phytochrome B (phyB), the primary red light photoreceptor, promotes photomorphogenesis in Arabidopsis by interacting with the basic helix-loop-helix transcriptional factor PIF3 and inducing its phosphorylation and degradation. Heterotrimeric G proteins are known to regulate various developmental processes in plants and animals. In Arabidopsis, the G-protein β subunit AGB1 is known to repress photomorphogenesis. However, whether and how phyB and AGB1 coordinately regulate photomorphogenesis are largely unknown. Here we show that phyB physically interacts with AGB1 in a red light-dependent manner and that AGB1 interacts directly with PIF3. Moreover, we demonstrate that the AGB1-PIF3 interaction inhibits the association of PIF3 with phyB, leading to reduced phosphorylation and degradation of PIF3, whereas the phyB-AGB1 interaction represses the association of PIF3 with AGB1, resulting in enhaneed phosphorylation and degradation of PIF3. Our results suggest that phyB and AGB1 antagonistically regulate PIF3 stability by dynamically interacting with each other and PIF3. This dynamic mechanism may allow plants to balanee phyB and G-protein signaling to optimize photomorphogenesis.
