Regulatory Functions of ZmMYB31 and ZmMYB42 in Maize Phenylpropanoid Pathway
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University of Toledo / OhioLINK
2011
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ndltd-OhioLink-oai-etd.ohiolink.edu-toledo13022950472021-08-03T06:07:48Z Regulatory Functions of ZmMYB31 and ZmMYB42 in Maize Phenylpropanoid Pathway Shi, Xinhui Biology Botany Molecular Biology MYB31 MYB42 phenylpropanoid pathway gene regulation maize ChIP-Seq The transcription factors ZmMYB31 and ZmMYB42 were previously linked to the negative regulation of the lignin biosynthetic pathway by overexpression in Arabidopsis, but their functions had not been determined in maize. Using SELEX assays, the consensus DNA-binding site of ZmMYB31 was shown to correspond to the canonical ACII element (ACCT/AACC) recognized by typical R2R3-MYB factors. Electrophorectic mobility shift assays indicated that both proteins strongly interact with a conserved ACII element in the maize caffeic acid O-methyltransferase (COMT) gene promoter in vitro, and that ZmMYB42 can also bind to an ACIII element. Chromatin immunoprecipitation (ChIP) assays and transient expression assays demonstrated that ZmMYB31 and ZmMYB42 share a set of overlapping but also distinct target genes in planta. Both directly repress and interact with the lignin ZmCOMT and flavonoid ZmA1 genes promoters in vivo. However ZmMYB31 can use either ACII element for efficient repression of COMT, whereas ZmMYB42 only binds the 2nd upstream ACII element. Furthermore, ZmMYB31 interacts with the ZmF5H gene promoter while ZmMYB42 interacts with the maize Zm4CL2 gene promoter in vivo. Initial results from ChIP followed by high-throughput sequencing (ChIP-Seq), shows genes in the most enriched function category belong to TF families. This suggests that their regulatory roles extend beyond the lignin pathway and point to an even more complex regulatory network than previously recognized. In addition, yeast two-hybrid studies suggest that ZmMYB42 interacts with the ZmR bHLH TF that is a well studied co-regulator of ZmC1, an R2R3-MYB required for anthocyanin regulation. These findings suggest that MYB domains play important roles in combinatorial transcriptional regulation. ZmR can affect the repression of ZmCOMT by ZmMYB31 and ZmMYB42, but following mutation of MYB binding sites in the COMT promoter ZmR cannot activate COMT gene expression, suggesting ZmR might interact with other unknown MYB protein to activate COMT in planta. This characterization of ZmMYB42 and ZmMYB31 shows that these two closely related factors play non-redundant functions in the regulation of the phenylpropanoid pathway and beyond. Indeed, although ZmMYB31 and ZmMYB42 were first implicated as phenylpropanoid pathway regulators, our results suggest that they are part of a much wider regulatory network. 2011-06-10 English text University of Toledo / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=toledo1302295047 http://rave.ohiolink.edu/etdc/view?acc_num=toledo1302295047 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Biology Botany Molecular Biology MYB31 MYB42 phenylpropanoid pathway gene regulation maize ChIP-Seq |
| spellingShingle |
Biology Botany Molecular Biology MYB31 MYB42 phenylpropanoid pathway gene regulation maize ChIP-Seq Shi, Xinhui Regulatory Functions of ZmMYB31 and ZmMYB42 in Maize Phenylpropanoid Pathway |
| author |
Shi, Xinhui |
| author_facet |
Shi, Xinhui |
| author_sort |
Shi, Xinhui |
| title |
Regulatory Functions of ZmMYB31 and ZmMYB42 in Maize Phenylpropanoid Pathway |
| title_short |
Regulatory Functions of ZmMYB31 and ZmMYB42 in Maize Phenylpropanoid Pathway |
| title_full |
Regulatory Functions of ZmMYB31 and ZmMYB42 in Maize Phenylpropanoid Pathway |
| title_fullStr |
Regulatory Functions of ZmMYB31 and ZmMYB42 in Maize Phenylpropanoid Pathway |
| title_full_unstemmed |
Regulatory Functions of ZmMYB31 and ZmMYB42 in Maize Phenylpropanoid Pathway |
| title_sort |
regulatory functions of zmmyb31 and zmmyb42 in maize phenylpropanoid pathway |
| publisher |
University of Toledo / OhioLINK |
| publishDate |
2011 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1302295047 |
| work_keys_str_mv |
AT shixinhui regulatoryfunctionsofzmmyb31andzmmyb42inmaizephenylpropanoidpathway |
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1719431428247126016 |