Ectopic expression of MYB46 identifies transcriptional regulatory genes involved in secondary wall biosynthesis in Arabidopsis

Ko, Jae‐Heung; Kim, Won Chan; Han, Kyung Hwan

doi:10.1111/j.1365-313x.2009.03989.x

Cited by 265 publications

(300 citation statements)

References 65 publications

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“…Specifically, its overexpression affects the expression of several cell wall biosynthesis genes, although it does not influence secondary wall thickness, and dominant repression of its expression results in a reduction in secondary cell wall thickening (Ko et al, 2009;Zhong et al, 2008). Here, we demonstrated that AtMYB52 is involved in ABA response during postgermination growth.…”

Section: Discussionmentioning

confidence: 78%

“…For instance, MYB58 and MYB63 are regulators of lignin biosynthesis (Zhou et al, 2009), and MYB103, MYB85, MYB52 and MYB54 control secondary wall thickening (Zhong et al, 2008). Among the MYB transcription factors, hierarchical relationships exist, and it has been demonstrated that MYB52 is a downstream target of MY46, which is a master switch for secondary cell wall formation in Arabidopsis (Ko et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

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Overexpression of AtMYB52 Confers ABA Hypersensitivity and Drought Tolerance

Park

Kang

Kim

2011

Molecules and Cells

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We carried out activation tagging screen to isolate genes regulating abscisic acid (ABA) response. From the screen of approximately 10,000 plants, we isolated ca 100 ABA response mutants. We characterized one of the mutants, designated ahs1, in this study. The mutant is ABAhypersensitive, and AtMYB52 was found to be activated in the mutant. Overexpression analysis to recapitulate the mutant phenotypes demonstrated that ATMYB confers ABA-hypersensitivity during postgermination growth. Additionally, AtMYB52 overexpression lines were droughttolerant and their seedlings were salt-sensitive. Changes in the expression levels of a few genes involved in ABA response or cell wall biosynthesis were also observed. Together, our data suggest that AtMYB52 is involved in ABA response. Others previously demonstrated that At-MYB52 regulates cell wall biosynthesis; thus, our results imply a possible connec-tion between ABA response and cell wall biosynthesis.

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Section: Discussionmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Overexpression of AtMYB52 Confers ABA Hypersensitivity and Drought Tolerance

Park

Kang

Kim

2011

Molecules and Cells

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“…Recently several studies have been reported that some of these transcription factors are downstream of the VND/NST/SND1 (Ko et al 2009;McCarthy et al 2009;Yamaguchi et al 2010aYamaguchi et al , 2010Zhong et al 2007aZhong et al , 2008Zhou et al 2009). Particularly, MYB46, MYB83, MYB103, and KNOTTED1-LIKE HOMEODOMAIN PROTEIN 7 (KNAT7) are direct targets of SND1/NST3/ANAC012 and possibly of NST1, VND6, and VND7 (Figure 3; Ko et al 2009;McCarthy et al 2009;Zhong et al 2007a). Overexpression of MYB46 or MYB83 activates gene expression of biosynthetic pathways of cellulose, hemicellulose and lignin and induces ectopic secondary wall formation (Ko et al 2009;McCarthy et al 2009;Zhong et al 2007a).…”

Section: Downstream Targets Of Vnd and Nst Proteinsmentioning

confidence: 99%

Transcriptional regulation of secondary wall formation controlled by NAC domain proteins

Yamaguchi

Demura

2010

Plant Biotechnology

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The plant vascular tissue consists of phloem and xylem. Phloem transports nutrients such as amino acids and sucrose. Xylem functions in the conduction of water and minerals throughout the plant and also supports the plant body. One of the characteristic features of xylem cells is a secondary wall structure between plasma membrane and (primary) cell wall. Studies on differentiation of xylem cells have been considered a good model system for the analysis of cell differentiation in higher plants because there are several well-established in vitro induction systems, in which isolated cells or suspension cultured cells from various plants transdifferentiate into xylem cells (reviewed in Fukuda 1996(reviewed in Fukuda , 2004 Turner et al. 2007). Recent interest in biofuels has raised the possibility that a better understanding of xylem development can be utilized for the improvement of plant biomass, since major portions of wood, which represents one of important sources of woody biomass, is mainly composed of two types of xylem cells, xylem vessels and fiber cells. Moreover, main components of the secondary wall are polysaccharides, cellulose, and hemicellulose, which are expected to be good starting materials for the production of bioethanol and bioplastics.Transcription factors are proteins that have function in controlling the expression of target genes quantitatively, temporally, and spatially. To date, genetic analyses have revealed a number of transcription factors regulating vascular development (reviewed in Ariel et al. 2007;Carlsbecker and Helariutta 2005;Demura and Fukuda 2007). Moreover, reverse genetic approaches have been successful in isolating several NAC (which stands for NAM, ATAF1/2 and CUC2) domain transcription factors that control the specification of xylem cells accompanied by secondary wall formation. In this review, we summarize the function and regulation of the NAC domain proteins controlling secondary wall formation.VND/NST/SND1 subfamily of NAC domain proteins regulate secondary wall formation Previously, we established in vitro transdifferentiation systems, in which zinnia mesophyll cells and Arabidopsis suspension cells could synchronously transdifferentiate into tracheary elements at a high frequency. By using microarray analysis we identified a number of genes whose expression is elevated during the transdifferentiation processes (Demura et al. 2002;Kubo et al. 2005), including the following genes belonging to a subfamily of the NAC transcription factor family: zinnia Ze567 and Arabidopsis VND1 to VND7 (Figure 1). Abstract Woody cells develop secondary wall structure that mainly consists of polysaccharides (cellulose and hemicellulose) and lignin. These components are expected to be new sources of biofuels and biomaterials. Therefore, it is important to understand the molecular mechanism underlying secondary wall formation and how it contributes to plant biomass. Plant-specific NAC domain transcription factor family has been shown to be involved in diverse biological functions. Recen...

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“…Two MYB genes, PtrMYB021 (30) and PtrMYB52 (Table S5), are present in second layer, and two NAC genes, PtrSND1-A2 and PtrVND6-C2 (30), are in the third layer. PtrMYB021 is the poplar ortholog of Arabidopsis AtMYB46, known to up-regulate AtLAC10 and other laccase genes through an eight-nucleotide core motif (RKTWGGTR) (31,32), further validating the GRN. We also found some genes with unknown functions in the GRN.…”

Section: Down-regulation Of Ptrlac Transcript Abundance By Overexpresmentioning

confidence: 99%

Ptr-miR397a is a negative regulator of laccase genes affecting lignin content in Populus trichocarpa

Wei

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

358

339

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Laccases, as early as 1959, were proposed to catalyze the oxidative polymerization of monolignols. Genetic evidence in support of this hypothesis has been elusive due to functional redundancy of laccase genes. An Arabidopsis double mutant demonstrated the involvement of laccases in lignin biosynthesis. We previously identified a subset of laccase genes to be targets of a microRNA (miRNA) ptr-miR397a in Populus trichocarpa. To elucidate the roles of ptr-miR397a and its targets, we characterized the laccase gene family and identified 49 laccase gene models, of which 29 were predicted to be targets of ptr-miR397a. We overexpressed PtrMIR397a in transgenic P. trichocarpa. In each of all nine transgenic lines tested, 17 PtrLACs were down-regulated as analyzed by RNAseq. Transgenic lines with severe reduction in the expression of these laccase genes resulted in an ∼40% decrease in the total laccase activity. Overexpression of Ptr-MIR397a in these transgenic lines also reduced lignin content, whereas levels of all monolignol biosynthetic gene transcripts remained unchanged. A hierarchical genetic regulatory network (GRN) built by a bottom-up graphic Gaussian model algorithm provides additional support for a role of ptr-miR397a as a negative regulator of laccases for lignin biosynthesis. Full transcriptome-based differential gene expression in the overexpressed transgenics and protein domain analyses implicate previously unidentified transcription factors and their targets in an extended hierarchical GRN including ptr-miR397a and laccases that coregulate lignin biosynthesis in wood formation. Ptr-miR397a, laccases, and other regulatory components of this network may provide additional strategies for genetic manipulation of lignin content.L ignin, an abundant biological polymer affecting the ecology of the terrestrial biosphere, is vital for the integrity of plant cell walls, the strength of stems, and resistance against pests and pathogens (1). Lignin is also a major barrier in the pulping and biomass-to-ethanol processes (2-4). For extracting cellulose (pulping) or for enzymatic degradation of cellulose for bioethanol, harsh chemical or physical treatments are used to reduce interactions with lignin or other cell wall components (2-4). Reducing lignin content or altering lignin structure to reduce its recalcitrance are major goals for more efficient processing.Lignin is polymerized primarily from three monolignol precursors, p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol (1, 5). Over five decades, efforts have been made to understand the biosynthesis of the primary monolignols and to modify the quantity or composition of lignin. The polymerization of monolignols into a lignin polymer has long been thought to occur through oxidative polymerization catalyzed by either laccases or peroxidases (6). The mechanisms and specificity of the roles of the oxidative enzymes in lignin polymerization have been controversial (7).Laccases (EC. 1.10.3.2) are multicopper oxidoreductases. Plant laccase was the first enzyme sh...

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Ectopic expression of MYB46 identifies transcriptional regulatory genes involved in secondary wall biosynthesis in Arabidopsis

Cited by 265 publications

References 65 publications

Overexpression of AtMYB52 Confers ABA Hypersensitivity and Drought Tolerance

Overexpression of AtMYB52 Confers ABA Hypersensitivity and Drought Tolerance

Transcriptional regulation of secondary wall formation controlled by NAC domain proteins

Ptr-miR397a is a negative regulator of laccase genes affecting lignin content in Populus trichocarpa

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