Conserved and None-Conserved Functions of the Rice Homologs of the Arabidopsis Trichome Initiation-Regulating MBW Complex Proteins

2020 ◽  
Author(s):  
Kaijie Zheng ◽  
Xutong Wang ◽  
Yating Wang ◽  
Shucai Wang
Keyword(s):  
Transcription Factor ◽  
Anthocyanin Biosynthesis ◽  
Transcriptional Activator ◽  
Myb Transcription Factor ◽  
Bhlh Transcription Factor ◽  
Seed Color ◽  
Transcription Activator ◽  
Root Hair Formation ◽  
Protoplast Transfection ◽  
Mbw Complex

Abstract Background: Trichome initiation in Arabidopsis is regulated by a MYB-bHLH-WD40 (MBW) transcriptional activator complex formed by the R2R3 MYB transcription factor GLABRA1 (GL1), MYB23 or MYB82, the bHLH transcription factor GLABRA3 (GL3), ENHANCER OF GLABRA3 (EGL3) or TRANSPARENT TESTA8 (TT8), and the WD40-repeat protein TRANSPARENT TESTA GLABRA1 (TTG1). However, the functions of the rice homologs of the MBW complex proteins remained uncharacterized. Results: Based on amino acid sequence identity and similarity, and protein interaction prediction, we identified OsGL1s, OsGL3s and OsTTG1s as rice homologs of the MBW complex proteins. By using protoplast transfection, we show that OsGL1D, OsGL1E, OsGL3B and OsTTG1A were predominantly localized in the nucleus, OsGL3B functions as a transcriptional activator and is able to interact with GL1 and TTG1. By using yeast two hybridization and protoplast transfection assays, we show that OsGL3B is able to interact with OsGL1E and OsTTG1A, and OsGL1E and OsTTG1A are also able to interact with GL3. On the other hand, we found that OsGL1D functions as a transcription activator, and it can interact with GL3 but not OsGL3B. These results suggest that rice homologs of the Arabidopsis MBW complex proteins are able to form MBW complexes, but may have conserved and none-conserved functions. Furthermore, we found that expression of OsTTG1A in the ttg1 mutant restored the phenotypes including alternations in trichome and root hair formation, seed color, mucilage production and anthocyanin biosynthesis, indicating that OsTTG1A and TTG1 may have similar functions. Conclusion: These results aid in our understanding of the mechanism of trichome initiation in rice.

scholarly journals Conserved and non-conserved functions of the rice homologs of the Arabidopsis trichome initiation-regulating MBW complex proteins

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kaijie Zheng ◽  
Xutong Wang ◽  
Yating Wang ◽  
Shucai Wang
Keyword(s):  
Transcription Factor ◽  
Anthocyanin Biosynthesis ◽  
Transcriptional Activator ◽  
Myb Transcription Factor ◽  
Bhlh Transcription Factor ◽  
Seed Color ◽  
Transcription Activator ◽  
Root Hair Formation ◽  
Protoplast Transfection ◽  
Mbw Complex

Abstract Background Trichome initiation in Arabidopsis is regulated by a MYB-bHLH-WD40 (MBW) transcriptional activator complex formed by the R2R3 MYB transcription factor GLABRA1 (GL1), MYB23 or MYB82, the bHLH transcription factor GLABRA3 (GL3), ENHANCER OF GLABRA3 (EGL3) or TRANSPARENT TESTA8 (TT8), and the WD40-repeat protein TRANSPARENT TESTA GLABRA1 (TTG1). However, the functions of the rice homologs of the MBW complex proteins remained uncharacterized. Results Based on amino acid sequence identity and similarity, and protein interaction prediction, we identified OsGL1s, OsGL3s and OsTTG1s as rice homologs of the MBW complex proteins. By using protoplast transfection, we show that OsGL1D, OsGL1E, OsGL3B and OsTTG1A were predominantly localized in the nucleus, OsGL3B functions as a transcriptional activator and is able to interact with GL1 and TTG1. By using yeast two-hybrid and protoplast transfection assays, we show that OsGL3B is able to interact with OsGL1E and OsTTG1A, and OsGL1E and OsTTG1A are also able to interact with GL3. On the other hand, we found that OsGL1D functions as a transcription activator, and it can interact with GL3 but not OsGL3B. Furthermore, our results show that expression of OsTTG1A in the ttg1 mutant restored the phenotypes including alternations in trichome and root hair formation, seed color, mucilage production and anthocyanin biosynthesis, indicating that OsTTG1A and TTG1 may have similar functions. Conclusion These results suggest that the rice homologs of the Arabidopsis MBW complex proteins are able to form MBW complexes, but may have conserved and non-conserved functions.

An R2R3-MYB transcription factor CmMYB21 represses anthocyanin biosynthesis in color fading petals of chrysanthemum

2022 ◽  
Vol 293 ◽  
pp. 110674
Author(s):  
Yiguang Wang ◽  
Li-Jie Zhou ◽  
Yuxi Wang ◽  
Zhiqiang Geng ◽  
Baoqing Ding ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Anthocyanin Biosynthesis ◽  
Myb Transcription Factor ◽  
Color Fading ◽  
R2r3 Myb

scholarly journals Tomato bHLH132 Transcription Factor Controls Growth and Defense and Is Activated by Xanthomonas euvesicatoria Effector XopD During Pathogenesis

2019 ◽  
Vol 32 (12) ◽  
pp. 1614-1622 ◽  
Author(s):  
Jung-Gun Kim ◽  
Mary Beth Mudgett
Keyword(s):  
Transcription Factor ◽  
Protease Activity ◽  
Transcriptional Profiling ◽  
Bhlh Transcription Factor ◽  
Transcription Activator ◽  
Tal Effectors ◽  
Sumo Protease ◽  
Tal Effector ◽  
Helix Loop Helix ◽  
Xanthomonas Euvesicatoria

Effector-dependent manipulation of host transcription is a key virulence mechanism used by Xanthomonas species causing bacterial spot disease in tomato and pepper. Transcription activator-like (TAL) effectors employ novel DNA-binding domains to directly activate host transcription, whereas the non-TAL effector XopD uses a small ubiquitin-like modifier (SUMO) protease activity to represses host transcription. The targets of TAL and non-TAL effectors provide insight to the genes governing susceptibility and resistance during Xanthomonas infection. In this study, we investigated the extent to which the X. euvesicatoria non-TAL effector strain Xe85-10 activates tomato transcription to gain new insight to the transcriptional circuits and virulence mechanisms associated with Xanthomonas euvesicatoria pathogenesis. Using transcriptional profiling, we identified a putative basic helix-loop-helix (bHLH) transcription factor, bHLH132, as a pathogen-responsive gene that is moderately induced by microbe-associated molecular patterns and defense hormones and is highly induced by XopD during X. euvesicatoria infection. We also found that activation of bHLH132 transcription requires the XopD SUMO protease activity. Silencing bHLH132 mRNA expression results in stunted tomato plants with enhanced susceptibility to X. euvesicatoria infection. Our work suggests that bHLH132 is required for normal vegetative growth and development as well as resistance to X. euvesicatoria. It also suggests new transcription-based models describing XopD virulence and recognition in tomato.

scholarly journals A R2R3-MYB Transcription Factor, VvMYBC2L2, Functions as a Transcriptional Repressor of Anthocyanin Biosynthesis in Grapevine (Vitis vinifera L.)

Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 92 ◽  
Author(s):  
Ziguo Zhu ◽  
Guirong Li ◽  
Li Liu ◽  
Qingtian Zhang ◽  
Zhen Han ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Vitis Vinifera ◽  
Anthocyanin Biosynthesis ◽  
Transcriptional Repressor ◽  
Negative Regulator ◽  
Myb Transcription Factor ◽  
Vitis Vinifera L ◽  
Flavonoid Pathway ◽  
Leucoanthocyanidin Reductase ◽  
R2r3 Myb

In grapevine, the MYB transcription factors play an important role in the flavonoid pathway. Here, a R2R3-MYB transcription factor, VvMYBC2L2, isolated from Vitis vinifera cultivar Yatomi Rose, may be involved in anthocyanin biosynthesis as a transcriptional repressor. VvMYBC2L2 was shown to be a nuclear protein. The gene was shown to be strongly expressed in root, flower and seed tissue, but weakly expressed during the fruit development in grapevine. Overexpressing the VvMYBC2L2 gene in tobacco resulted in a very marked decrease in petal anthocyanin concentration. Expression analysis of flavonoid biosynthesis structural genes revealed that chalcone synthase (CHS), dihydroflavonol 4-reductase (DFR), leucoanthocyanidin reductase (LAR) and UDP glucose flavonoid 3-O-glucosyl transferase (UFGT) were strongly down-regulated in the VvMYBC2L2-overexpressed tobacco. In addition, transcription of the regulatory genes AN1a and AN1b was completely suppressed in transgenic plants. These results suggested that VvMYBC2L2 plays a role as a negative regulator of anthocyanin biosynthesis.

scholarly journals CsMYB3 and CsRuby1 form an ‘Activator-and-Repressor’ Loop for the Regulation of Anthocyanin Biosynthesis in Citrus

2019 ◽  
Vol 61 (2) ◽  
pp. 318-330 ◽  
Author(s):  
Ding Huang ◽  
Zhouzhou Tang ◽  
Jialing Fu ◽  
Yue Yuan ◽  
Xiuxin Deng ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Anthocyanin Biosynthesis ◽  
Myb Transcription Factor ◽  
Nitrogen Stress ◽  
Loop Model ◽  
Anthocyanin Accumulation ◽  
Promoter Activation ◽  
R2r3 Myb ◽  
Activation Capacity ◽  
Anthocyanin Biosynthetic Genes

Abstract Anthocyanins are preferentially accumulated in certain tissues of particular species of citrus. A R2R3-MYB transcription factor (named Ruby1) has been well documented as an activator of citrus anthocyanin biosynthesis. In this study, we characterized CsMYB3, a transcriptional repressor that regulates anthocyanin biosynthesis in citrus. CsMYB3 was expressed in anthocyanin-pigmented tissues, and the expression was closely associated with that of Ruby1, which is a key anthocyanin activator. Overexpression of CsMYB3 in Arabidopsis resulted in a decrease in anthocyanins under nitrogen stress. Overexpression of CsMYB3 in the background of CsRuby1-overexpressing strawberry and Arabidopsis reduced the anthocyanin accumulation level. Transient promoter activation assays revealed that CsMYB3 could repress the activation capacity of the complex formed by CsRuby1/CsbHLH1 for the anthocyanin biosynthetic genes. Moreover, CsMYB3 could be transcriptionally activated by CsRuby1 via promoter binding, thus forming an ‘activator-and-repressor’ loop to regulate anthocyanin biosynthesis in citrus. This study shows that CsMYB3 plays a repressor role in the regulation of anthocyanin biosynthesis and proposes an ‘activator-and-repressor’ loop model constituted by CsRuby1 and CsMYB3 in the regulation of anthocyanin biosynthesis in citrus.

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