scholarly journals Histone Deacetylase HDT1 is Involved in Stem Vascular Development in Arabidopsis

2019 ◽  
Vol 20 (14) ◽  
pp. 3452 ◽  
Author(s):  
Yongzhuo Zhang ◽  
Bin Yin ◽  
Jiaxue Zhang ◽  
Ziyi Cheng ◽  
Yadi Liu ◽  
...  

Histone acetylation and deacetylation play essential roles in eukaryotic gene regulation. HD2 (HD-tuins) proteins were previously identified as plant-specific histone deacetylases. In this study, we investigated the function of the HDT1 gene in the formation of stem vascular tissue in Arabidopsis thaliana. The height and thickness of the inflorescence stems in the hdt1 mutant was lower than that of wild-type plants. Paraffin sections showed that the cell number increased compared to the wild type, while transmission electron microscopy showed that the size of individual tracheary elements and fiber cells significantly decreased in the hdt1 mutant. In addition, the cell wall thickness of tracheary elements and fiber cells increased. We also found that the lignin content in the stem of the hdt1 mutants increased compared to that of the wild type. Transcriptomic data revealed that the expression levels of many biosynthetic genes related to secondary wall components, including cellulose, lignin biosynthesis, and hormone-related genes, were altered, which may lead to the altered phenotype in vascular tissue of the hdt1 mutant. These results suggested that HDT1 is involved in development of the vascular tissue of the stem by affecting cell proliferation and differentiation.

2018 ◽  
Vol 54 (No. 1) ◽  
pp. 26-29
Author(s):  
J. Meng ◽  
C. Li ◽  
M. Zhao ◽  
C. Wang ◽  
Y. Ru ◽  
...  

The Antisense 4CL gene was transfected into alfalfa through Agrobacterium-mediated transfer. The test results indicated that the antisense 4CL gene was successfully integrated into the genome DNA of alfalfa and was stably transmitted to the offspring. Compared to the wild-type plants, the lignin content of T<sub>0</sub> and T<sub>1</sub> generation plants was reduced by 45.77% and 31.97%, respectively; there were no significant differences in height and weight of T<sub>0</sub> and T<sub>1</sub> plants, compared to the wild-type plants. However, the transgenic plant differed from the wild-type plant by softer stems and leaves, larger leaves, fewer flowers and a fewer seeds. The T<sub>0</sub> line was susceptible to disease infection, but significantly improved in the second year. The results suggest that the 4CL gene from Amorpha fruticosa can be used to regulate lignin biosynthesis in transgenic forage crops.


2021 ◽  
Vol 11 ◽  
Author(s):  
Ying Yu ◽  
Huizi Liu ◽  
Nan Zhang ◽  
Caiqiu Gao ◽  
Liwang Qi ◽  
...  

The MYB (v-myb avian myeloblastosis viral oncogene homolog) family is one of the largest transcription factor families in plants, and is widely involved in the regulation of plant metabolism. In this study, we show that a MYB4 transcription factor, BpMYB4, identified from birch (Betula platyphylla Suk.) and homologous to EgMYB1 from Eucalyptus robusta Smith and ZmMYB31 from Zea mays L. is involved in secondary cell wall synthesis. The expression level of BpMYB4 was higher in flowers relative to other tissues, and was induced by artificial bending and gravitational stimuli in developing xylem tissues. The expression of this gene was not enriched in the developing xylem during the active season, and showed higher transcript levels in xylem tissues around sprouting and near the dormant period. BpMYB4 also was induced express by abiotic stress. Functional analysis indicated that expression of BpMYB4 in transgenic Arabidopsis (Arabidopsis thaliana) plants could promote the growth of stems, and result in increased number of inflorescence stems and shoots. Anatomical observation of stem sections showed lower lignin deposition, and a chemical contents test also demonstrated increased cellulose and decreased lignin content in the transgenic plants. In addition, treatment with 100 mM NaCl and 200 mM mannitol resulted in the germination rate of the over-expressed lines being higher than that of the wild-type seeds. The proline content in transgenic plants was higher than that in WT, but MDA content was lower than that in WT. Further investigation in birch using transient transformation techniques indicated that overexpression of BpMYB4 could scavenge hydrogen peroxide and O2.– and reduce cell damage, compared with the wild-type plants. Therefore, we believe that BpMYB4 promotes stem development and cellulose biosynthesis as an inhibitor of lignin biosynthesis, and has a function in abiotic stress resistance.


2020 ◽  
Vol 21 (11) ◽  
pp. 3993 ◽  
Author(s):  
Shaofeng Li ◽  
Yaoxiang Zhang ◽  
Xuebing Xin ◽  
Changjun Ding ◽  
Fuling Lv ◽  
...  

Osmotin-like proteins (OLPs) mediate defenses against abiotic and biotic stresses and fungal pathogens in plants. However, no OLPs have been functionally elucidated in poplar. Here, we report an osmotin-like protein designated PdOLP1 from Populus deltoides (Marsh.). Expression analysis showed that PdOLP1 transcripts were mainly present in immature xylem and immature phloem during vascular tissue development in P. deltoides. We conducted phenotypic, anatomical, and molecular analyses of PdOLP1-overexpressing lines and the PdOLP1-downregulated hybrid poplar 84K (Populus alba × Populus glandulosa) (Hybrid poplar 84K PagOLP1, PagOLP2, PagOLP3 and PagOLP4 are highly homologous to PdOLP1, and are downregulated in PdOLP1-downregulated hybrid poplar 84K). The overexpression of PdOLP1 led to a reduction in the radial width and cell layer number in the xylem and phloem zones, in expression of genes involved in lignin biosynthesis, and in the fibers and vessels of xylem cell walls in the overexpressing lines. Additionally, the xylem vessels and fibers of PdOLP1-downregulated poplar exhibited increased secondary cell wall thickness. Elevated expression of secondary wall biosynthetic genes was accompanied by increases in lignin content, dry weight biomass, and carbon storage in PdOLP1-downregulated lines. A PdOLP1 coexpression network was constructed and showed that PdOLP1 was coexpressed with a large number of genes involved in secondary cell wall biosynthesis and wood development in poplar. Moreover, based on transcriptional activation assays, PtobZIP5 and PtobHLH7 activated the PdOLP1 promoter, whereas PtoBLH8 and PtoWRKY40 repressed it. A yeast one-hybrid (Y1H) assay confirmed interaction of PtoBLH8, PtoMYB3, and PtoWRKY40 with the PdOLP1 promoter in vivo. Together, our results suggest that PdOLP1 is a negative regulator of secondary wall biosynthesis and may be valuable for manipulating secondary cell wall deposition to improve carbon fixation efficiency in tree species.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Juan Carlos Serrani-Yarce ◽  
Luis Escamilla-Trevino ◽  
Jaime Barros ◽  
Lina Gallego-Giraldo ◽  
Yunqiao Pu ◽  
...  

Abstract Background Hydroxycinnamoyl CoA: shikimate hydroxycinnamoyl transferase (HCT) is a central enzyme of the so-called “esters” pathway to monolignols. As originally envisioned, HCT functions twice in this pathway, to form coumaroyl shikimate and then, in the “reverse” direction, to convert caffeoyl shikimate to caffeoyl CoA. The discovery of a caffeoyl shikimate esterase (CSE) that forms caffeic acid directly from caffeoyl shikimate calls into question the need for the reverse HCT reaction in lignin biosynthesis. Loss of function of HCT gives severe growth phenotypes in several dicot plants, but less so in some monocots, questioning whether this enzyme, and therefore the shikimate shunt, plays the same role in both monocots and dicots. The model grass Brachypodium distachyon has two HCT genes, but lacks a classical CSE gene. This study was therefore conducted to evaluate the utility of HCT as a target for lignin modification in a species with an “incomplete” shikimate shunt. Results The kinetic properties of recombinant B. distachyon HCTs were compared with those from Arabidopsis thaliana, Medicago truncatula, and Panicum virgatum (switchgrass) for both the forward and reverse reactions. Along with two M. truncatula HCTs, B. distachyon HCT2 had the least kinetically unfavorable reverse HCT reaction, and this enzyme is induced when HCT1 is down-regulated. Down regulation of B. distachyon HCT1, or co-down-regulation of HCT1 and HCT2, by RNA interference led to reduced lignin levels, with only modest changes in lignin composition and molecular weight. Conclusions Down-regulation of HCT1, or co-down-regulation of both HCT genes, in B. distachyon results in less extensive changes in lignin content/composition and cell wall structure than observed following HCT down-regulation in dicots, with little negative impact on biomass yield. Nevertheless, HCT down-regulation leads to significant improvements in biomass saccharification efficiency, making this gene a preferred target for biotechnological improvement of grasses for bioprocessing.


2005 ◽  
Vol 25 (8) ◽  
pp. 2924-2937 ◽  
Author(s):  
Kaoru Tominaga ◽  
Bhakti Kirtane ◽  
James G. Jackson ◽  
Yuji Ikeno ◽  
Takayoshi Ikeda ◽  
...  

ABSTRACT MRG15 is a highly conserved protein, and orthologs exist in organisms from yeast to humans. MRG15 associates with at least two nucleoprotein complexes that include histone acetyltransferases and/or histone deacetylases, suggesting it is involved in chromatin remodeling. To study the role of MRG15 in vivo, we generated knockout mice and determined that the phenotype is embryonic lethal, with embryos and the few stillborn pups exhibiting developmental delay. Immunohistochemical analysis indicates that apoptosis in Mrg15 − / − embryos is not increased compared with wild-type littermates. However, the number of proliferating cells is significantly reduced in various tissues of the smaller null embryos compared with control littermates. Cell proliferation defects are also observed in Mrg15 − / − mouse embryonic fibroblasts. The hearts of the Mrg15 − / − embryos exhibit some features of hypertrophic cardiomyopathy. The increase in size of the cardiomyocytes is most likely a response to decreased growth of the cells. Mrg15 − / − embryos appeared pale, and microarray analysis revealed that α-globin gene expression was decreased in null versus wild-type embryos. We determined by chromatin immunoprecipitation that MRG15 was recruited to the α-globin promoter during dimethyl sulfoxide-induced mouse erythroleukemia cell differentiation. These findings demonstrate that MRG15 has an essential role in embryonic development via chromatin remodeling and transcriptional regulation.


1999 ◽  
Vol 13 (19) ◽  
pp. 2490-2501 ◽  
Author(s):  
M. Murphy ◽  
J. Ahn ◽  
K. K. Walker ◽  
W. H. Hoffman ◽  
R. M. Evans ◽  
...  

Development ◽  
1992 ◽  
Vol 115 (3) ◽  
pp. 813-820
Author(s):  
L.L. Harris ◽  
J.C. Talian ◽  
P.S. Zelenka

The present study uses the polymerase chain reaction and in situ hybridization to examine c-myc and N-myc mRNA in the embryonic chicken lens at 6, 10, 14 and 19 days of development and compares the pattern of expression obtained with the developmental pattern of cell proliferation and differentiation. In the central epithelium, c-myc mRNA levels were proportional to the percentage of proliferating cells throughout development. N-myc mRNA expression in this region was relatively low and showed no correlation with cell proliferation. The ratio of N-myc to c-myc mRNA increased markedly with the onset of epithelial cell elongation and terminal fiber cell differentiation, although both c-myc and N-myc mRNAs continued to be expressed in postmitotic, elongating cells of the equatorial epithelium and in terminally differentiating lens fiber cells. Thus, increased expression of N-myc, a gene whose protein product may compete with c-myc protein for dimerization partners, accompanies the dissociation of c-myc expression and cell proliferation during terminal differentiation of lens fiber cells.


Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2625
Author(s):  
Nurashikin Kemat ◽  
Richard G. F. Visser ◽  
Frans A. Krens

One of the characteristics of hyperhydric plants is the reduction of cell wall lignification (hypolignification), but how this is related to the observed abnormalities of hyperhydricity (HH), is still unclear. Lignin is hydrophobic, and we speculate that a reduction in lignin levels leads to more capillary action of the cell wall and consequently to more water in the apoplast. p-coumaric acid is the hydroxyl derivative of cinnamic acid and a precursor for lignin and flavonoids in higher plant. In the present study, we examined the role of lignin in the development of HH in Arabidopsis thaliana by checking the wild-types (Ler and Col-0) and mutants affected in phenylpropanoid biosynthesis, in the gene coding for cinnamate 4-hydroxylase, C4H (ref3-1 and ref3-3). Exogenously applied p-coumaric acid decreased the symptoms of HH in both wild-type and less-lignin mutants. Moreover, the results revealed that exogenously applied p-coumaric acid inhibited root growth and increased the total lignin content in both wild-type and less-lignin mutants. These effects appeared to diminish the symptoms of HH and suggest an important role for lignin in HH.


2019 ◽  
Author(s):  
Philippe Golfier ◽  
Faride Unda ◽  
Emily K. Murphy ◽  
Jianbo Xie ◽  
Feng He ◽  
...  

AbstractCell wall recalcitrance is a major constraint for the exploitation of lignocellulosic biomass as renewable resource for energy and bio-based products. Transcriptional regulators of the lignin biosynthetic pathway represent promising targets for tailoring lignin content and composition in plant secondary cell walls. A wealth of research in model organisms has revealed that transcriptional regulation of secondary cell wall formation is orchestrated by a hierarchical transcription factor (TF) network with NAC TFs as master regulators and MYB factors in the lower tier regulators. However, knowledge about the transcriptional regulation of lignin biosynthesis in lignocellulosic feedstocks, such as Miscanthus, is limited. Here, we characterized two Miscanthus MYB TFs, MsSCM1 and MsMYB103, and compared their transcriptional impact with that of the master regulator MsSND1. In Miscanthus leaves MsSCM1 and MsMYB103 are expressed at growth stages associated with lignification. Ectopic expression of MsSCM1 and MsMYB103 in tobacco leaves was sufficient to trigger secondary cell wall deposition with distinct sugar and lignin composition. Moreover, RNA-seq analysis revealed that the transcriptional responses to MsSCM1 and MsMYB103 overexpression showed extensive overlap with the response to MsSND1, but were distinct from each other, underscoring the inherent complexity of secondary cell wall formation. Together, MsSCM1 and MsMYB103 represent interesting targets for manipulations of lignin content and composition in Miscanthus towards tailored biomass.


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