The AmMYB308 and AmMYB330 Transcription Factors from Antirrhinum Regulate Phenylpropanoid and Lignin Biosynthesis in Transgenic Tobacco

The secondary wall is the main part of wood and is composed of cellulose, xylan, lignin, and small amounts of structural proteins and enzymes. Lignin molecules can interact directly or indirectly with cellulose, xylan and other polysaccharide molecules in the cell wall, increasing the mechanical strength and hydrophobicity of plant cells and tissues and facilitating the long-distance transportation of water in plants. MYBs (v-myb avian myeloblastosis viral oncogene homolog) belong to one of the largest superfamilies of transcription factors, the members of which regulate secondary cell-wall formation by promoting/inhibiting the biosynthesis of lignin, cellulose, and xylan. Among them, MYB46 and MYB83, which comprise the second layer of the main switch of secondary cell-wall biosynthesis, coordinate upstream and downstream secondary wall synthesis-related transcription factors. In addition, MYB transcription factors other than MYB46/83, as well as noncoding RNAs, hormones, and other factors, interact with one another to regulate the biosynthesis of the secondary wall. Here, we discuss the biosynthesis of secondary wall, classification and functions of MYB transcription factors and their regulation of lignin polymerization and secondary cell-wall formation during wood formation.

Download Full-text

Expression of MYB transcription factor gene ZmMYB59 affects seed germination in Nicotiana tabacum and Oryza sativa

10.21203/rs.3.rs-19878/v1 ◽

2020 ◽

Author(s):

Kaihui Zhai ◽

Guangwu Zhao ◽

Hongye Jiang ◽

Caixia Sun ◽

Jingyu Ren

Keyword(s):

Transcription Factor ◽

Transcription Factors ◽

Seed Germination ◽

Transgenic Tobacco ◽

Germination Rate ◽

Myb Transcription Factor ◽

Transcription Factor Gene ◽

Factor Gene ◽

Myb Transcription Factors ◽

Vigor Index

Abstract Background MYB transcription factors are involved in many biological processes, including metabolism, development and responses to biotic and abiotic stresses. In our previous work, a new MYB transcription factor gene, ZmMYB59 was induced by deep sowing and down-regulated during maize seed germination via Real-Time PCR. However, there are few reports on seed germination regulated by MYB proteins and the functions of ZmMYB59 remain unknown. Results In this study, to examine its functions, Agrobacterium -mediated transformation was exploited to generate ZmMYB59 transgenic tobacco and rice. In T 2 generation transgenic tobacco, germination rate, germination index, vigor index and hypocotyl length were significantly decreased by 25.0~50.9%, 34.5~54.4%, 57.5~88.3% and 21.9~31.2% compared to wild-type (WT) lines. In T 2 generation transgenic rice, germination rate, germination index, vigor index and mesocotyl length were notably reduced by 39.1~53.8%, 51.4~71.4%, 52.5~74.0% and 28.3~41.5%, respectively. On this basis, relative physiological indicators were determined. The activities of catalase, peroxidase, superoxide dismutase, ascorbate peroxidase and proline content of transgenic lines were significantly lower than those of WT, suggesting that ZmMYB59 reduced their antioxidant capacity. As well, ZmMYB59 expression extremely inhibited the synthesis of gibberellin A1 (GA 1 ) and cytokinin (CTK), and promoted the synthesis of abscisic acid (ABA) concurrently, which implied that seed germination was repressed by ZmMYB59 in hormone levels. Furthermore, cell length and cell number of hypocotyl/mesocotyl in transgenic plants were notably decreased. Conclusions Taken together, it proposed that ZmMYB59 plays a negative regulation during seed germination in tobacco and rice, which also contributes to illuminate the molecular mechanisms regulated by MYB transcription factors.

Download Full-text

Homeostatic regulation of flavonoid and lignin biosynthesis in phenylpropanoid pathway of transgenic tobacco

Gene ◽

10.1016/j.gene.2021.146017 ◽

2021 ◽

pp. 146017

Author(s):

Jiewei Shi ◽

Xu Yan ◽

Tingting Sun ◽

Yuxiao Shen ◽

Qi Shi ◽

...

Keyword(s):

Transgenic Tobacco ◽

Lignin Biosynthesis ◽

Phenylpropanoid Pathway ◽

Homeostatic Regulation

Download Full-text

The in vivo impact of MsLAC1, a Miscanthus laccase isoform, on lignification and lignin composition contrasts with its in vitro substrate preference

BMC Plant Biology ◽

10.1186/s12870-019-2174-3 ◽

2019 ◽

Vol 19 (1) ◽

Author(s):

Feng He ◽

Katja Machemer-Noonan ◽

Philippe Golfier ◽

Faride Unda ◽

Johanna Dechert ◽

...

Keyword(s):

Cell Wall ◽

Transcription Factors ◽

Lignin Content ◽

Lignin Biosynthesis ◽

Lignin Composition ◽

Xylem Fibers ◽

Breeding Target

Abstract Background Understanding lignin biosynthesis and composition is of central importance for sustainable bioenergy and biomaterials production. Species of the genus Miscanthus have emerged as promising bioenergy crop due to their rapid growth and modest nutrient requirements. However, lignin polymerization in Miscanthus is poorly understood. It was previously shown that plant laccases are phenol oxidases that have multiple functions in plant, one of which is the polymerization of monolignols. Herein, we link a newly discovered Miscanthus laccase, MsLAC1, to cell wall lignification. Characterization of recombinant MsLAC1 and Arabidopsis transgenic plants expressing MsLAC1 were carried out to understand the function of MsLAC1 both in vitro and in vivo. Results Using a comprehensive suite of molecular, biochemical and histochemical analyses, we show that MsLAC1 localizes to cell walls and identify Miscanthus transcription factors capable of regulating MsLAC1 expression. In addition, MsLAC1 complements the Arabidopsis lac4–2 lac17 mutant and recombinant MsLAC1 is able to oxidize monolignol in vitro. Transgenic Arabidopsis plants over-expressing MsLAC1 show higher G-lignin content, although recombinant MsLAC1 seemed to prefer sinapyl alcohol as substrate. Conclusions In summary, our results suggest that MsLAC1 is regulated by secondary cell wall MYB transcription factors and is involved in lignification of xylem fibers. This report identifies MsLAC1 as a promising breeding target in Miscanthus for biofuel and biomaterial applications.

Download Full-text

CsMYB4a from Camellia sinensis Regulates the Auxin Signaling Pathway by Interacting with CsIAA4

10.1101/2021.10.11.463959 ◽

2021 ◽

Author(s):

Guoliang Ma ◽

Yingling Wu ◽

Changjuan Jiang ◽

Yifan Chen ◽

Dawei Xing ◽

...

Keyword(s):

Transcription Factors ◽

Signaling Pathway ◽

Transgenic Tobacco ◽

Camellia Sinensis ◽

Auxin Signaling ◽

Homologous Gene ◽

Naphthaleneacetic Acid ◽

Transgenic Tobacco Plants ◽

Tobacco Plants ◽

Auxin Signaling Pathway

Members of the R2R3-MYB4 subgroup are well-known negative regulatory transcription factors of phenylpropane and lignin pathways. In this study, we found that transgenic tobacco plants overexpressing a R2R3-MYB4 subgroup gene from Camellia sinensis (CsMYB4a) showed inhibited growth that was not regulated by phenylpropane and lignin pathways, and these plants exhibited altered sensitivity to synthetic auxin 1-naphthaleneacetic acid (α-NAA) treatment. An auxin/indole-3-acetic acid 4 (AUX/IAA4) gene from Camellia sinensis (CsIAA4) participating in the regulation of the auxin signal transduction pathway was screened from the yeast two-hybrid library with CsMYB4a as the bait protein, and tobacco plants overexpressing this gene showed a series of auxin-deficiency phenotypes, such as dwarfism, small leaves, reduced lateral roots, and a shorter primary root. CsIAA4 transgenic tobacco plants were less sensitive to exogenous α-NAA than control plants, which was consistent with the findings for CsMYB4a transgenic tobacco plants. The knockout of the endogenous NtIAA4 gene (a CsIAA4 homologous gene) in tobacco plants alleviated growth inhibition in CsMYB4a transgenic tobacco plants. Furthermore, protein-protein interaction experiments proved that domain II of CsIAA4 is the key motif for the interaction between CsIAA4 and CsMYB4a and that the degradation of CsIAA4 is prevented when CsMYB4a interacts with CsIAA4. In summary, our results suggest that CsMYB4a is a multifunctional transcription factor that regulates the auxin signaling pathway, phenylpropane and lignin pathways. This study provides new insights into the multiple functions of R2R3-MYB4 subgroup members as a group of well-known negative regulatory transcription factors.

Download Full-text

An Integrated Transcriptome and Proteome Analysis Reveals New Insights into Russeting of Bagging and Non-Bagging “Golden Delicious” Apple

International Journal of Molecular Sciences ◽

10.3390/ijms20184462 ◽

2019 ◽

Vol 20 (18) ◽

pp. 4462 ◽

Cited By ~ 1

Author(s):

Gaopeng Yuan ◽

Shuxun Bian ◽

Xiaolei Han ◽

Shanshan He ◽

Kai Liu ◽

...

Keyword(s):

Transcription Factors ◽

Molecular Mechanisms ◽

Developmental Stages ◽

Lignin Biosynthesis ◽

Proteome Analysis ◽

Differentially Expressed ◽

Proteomics Data ◽

Absolute Quantitation ◽

Physiological Disorder ◽

Golden Delicious

Apple skin russeting naturally occurs in many varieties, particularly in “Golden Delicious” and its pedigree, and is regarded as a non-invasive physiological disorder partly caused by excessive deposition of lignin. However, the understanding of its molecular mechanism is still limited. In this study, we used iTRAQ (isobaric tags for relative and absolute quantitation) and RNA-seq to detect the changes in the expression levels of genes and proteins in three developmental stages of russeting formation, in russeted (non-bagging) and non-russeted (bagging) skin of “Golden Delicious” apple. 2856 differentially expressed genes and 942 differentially expressed proteins in the comparison groups were detected at the transcript level and protein level, respectively. A correlation analysis of the transcriptomics and proteomics data revealed that four genes (MD03G1059200, MD08G1009200, MD17G1092400, and MD17G1225100) involved in lignin biosynthesis are significant changed during apple russeting formation. Additionally, 92 transcription factors, including 4 LIM transcription factors, may be involved in apple russeting formation. Among them, one LIM transcription factor (MD15G1068200) was capable of binding to the PAL-box like (CCACTTGAGTAC) element, which indicated it was potentially involved in lignin biosynthesis. This study will provide further views on the molecular mechanisms controlling apple russeting formation.

Download Full-text

PpNAC187 Enhances Lignin Synthesis in ‘Whangkeumbae’ Pear (Pyrus pyrifolia) ‘Hard-End’ Fruit

Molecules ◽

10.3390/molecules24234338 ◽

2019 ◽

Vol 24 (23) ◽

pp. 4338

Author(s):

Mingtong Li ◽

Chenxia Cheng ◽

Xinfu Zhang ◽

Suping Zhou ◽

Caihong Wang ◽

...

Keyword(s):

Transgenic Tobacco ◽

Lignin Content ◽

Lignin Biosynthesis ◽

Phenylpropanoid Pathway ◽

Pyrus Pyrifolia ◽

Rna Seq ◽

Pear Fruit ◽

Nac Transcription Factors ◽

Vessel Elements ◽

Leaf Tissues

A disorder in pears that is known as ‘hard-end’ fruit affects the appearance, edible quality, and market value of pear fruit. RNA-Seq was carried out on the calyx end of ‘Whangkeumbae’ pear fruit with and without the hard-end symptom to explore the mechanism underlying the formation of hard-end. The results indicated that the genes in the phenylpropanoid pathway affecting lignification were up-regulated in hard-end fruit. An analysis of differentially expressed genes (DEGs) identified three NAC transcription factors, and RT-qPCR analysis of PpNAC138, PpNAC186, and PpNAC187 confirmed that PpNAC187 gene expression was correlated with the hard-end disorder in pear fruit. A transient increase in PpNAC187 was observed in the calyx end of ‘Whangkeumbae’ fruit when they began to exhibit hard-end symptom. Concomitantly, the higher level of PpCCR and PpCOMT transcripts was observed, which are the key genes in lignin biosynthesis. Notably, lignin content in the stem and leaf tissues of transgenic tobacco overexpressing PpNAC187 was significantly higher than in the control plants that were transformed with an empty vector. Furthermore, transgenic tobacco overexpressing PpNAC187 had a larger number of xylem vessel elements. The results of this study confirmed that PpNAC187 functions in inducing lignification in pear fruit during the development of the hard-end disorder.

Download Full-text