scholarly journals Characterization of a sweet basil acyltransferase involved in eugenol biosynthesis

2020 ◽  
Vol 71 (12) ◽  
pp. 3638-3652 ◽  
Author(s):  
Niha Dhar ◽  
Sreelatha Sarangapani ◽  
Vaishnavi Amarr Reddy ◽  
Nadimuthu Kumar ◽  
Deepa Panicker ◽  
...  
Keyword(s):  
Lignin Content ◽  
Glandular Trichomes ◽  
Lignin Biosynthesis ◽  
Coniferyl Alcohol ◽  
Sweet Basil ◽  
Transgenic Lines ◽  
Common Substrate ◽  
Total Lignin

Abstract Sweet basil (Ocimum basilicum) plants produce its characteristic phenylpropene-rich essential oil in specialized structures known as peltate glandular trichomes (PGTs). Eugenol and chavicol are the major phenylpropenes produced by sweet basil varieties whose synthetic pathways are not fully elucidated. Eugenol is derived from coniferyl acetate by a reaction catalysed by eugenol synthase. An acyltransferase is proposed to convert coniferyl alcohol to coniferyl acetate which is the first committed step towards eugenol synthesis. Here, we perform a comparative next-generation transcriptome sequencing of different tissues of sweet basil, namely PGT, leaf, leaf stripped of PGTs (leaf–PGT), and roots, to identify differentially expressed transcripts specific to PGT. From these data, we identified a PGT-enriched BAHD acyltransferase gene ObCAAT1 and functionally characterized it. In vitro coupled reaction of ObCAAT1 with eugenol synthase in the presence of coniferyl alcohol resulted in eugenol production. Analysis of ObCAAT1-RNAi transgenic lines showed decreased levels of eugenol and accumulation of coniferyl alcohol and its derivatives. Coniferyl alcohol acts as a common substrate for phenylpropene and lignin biosynthesis. No differences were found in total lignin content of PGTs and leaves of transgenic lines, indicating that phenylpropene biosynthesis is not coupled to lignification in sweet basil.

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

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.

scholarly journals Sweet Basil Has Distinct Synthases for Eugenol Biosynthesis in Glandular Trichomes and Roots with Different Regulatory Mechanisms

2021 ◽  
Vol 22 (2) ◽  
pp. 681
Author(s):  
Vaishnavi Amarr Reddy ◽  
Chunhong Li ◽  
Kumar Nadimuthu ◽  
Jessica Gambino Tjhang ◽  
In-Cheol Jang ◽  
...  
Keyword(s):  
Glandular Trichomes ◽  
Functional Characterization ◽  
Rna Seq ◽  
Post Translational Modifications ◽  
E Coli ◽  
Sweet Basil ◽  
Specific Regulation

Production of a volatile phenylpropene; eugenol in sweet basil is mostly associated with peltate glandular trichomes (PGTs) found aerially. Currently only one eugenol synthase (EGS), ObEGS1 which belongs to PIP family is identified from sweet basil PGTs. Reports of the presence of eugenol in roots led us to analyse other EGSs in roots. We screened for all the PIP family reductase transcripts from the RNA-Seq data. In vivo functional characterization of all the genes in E. coli showed their ability to produce eugenol and were termed as ObEGS2-8. Among all, ObEGS1 displayed highest expression in PGTs and ObEGS4 in roots. Further, eugenol was produced only in the roots of soil-grown plants, but not in roots of aseptically-grown plants. Interestingly, eugenol production could be induced in roots of aseptically-grown plants under elicitation suggesting that eugenol production might occur as a result of environmental cues in roots. The presence of ObEGS4 transcript and protein in aseptically-grown plants indicated towards post-translational modifications (PTMs) of ObEGS4. Bioinformatics analysis showed possibility of phosphorylation in ObEGS4 which was further confirmed by in vitro experiment. Our study reveals the presence of multiple eugenol synthases in sweet basil and provides new insights into their diversity and tissue specific regulation.

scholarly journals Patatin-Related Phospholipase AtpPLAIIIα Affects Lignification of Xylem in Arabidopsis and Hybrid Poplars

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 451 ◽  
Author(s):  
Jin Hoon Jang ◽  
Ok Ran Lee
Keyword(s):  
Cell Walls ◽  
Lignin Content ◽  
Lignin Biosynthesis ◽  
Biofuel Production ◽  
Amide Bonds ◽  
Hybrid Poplars ◽  
Plant Lipids ◽  
Lipid Acyl Hydrolase ◽  
Specific Regulation

Lipid acyl hydrolase are a diverse group of enzymes that hydrolyze the ester or amide bonds of fatty acid in plant lipids. Patatin-related phospholipase AIIIs (pPLAIIIs) are one of major lipid acyl hydrolases that are less closely related to potato tuber patatins and are plant-specific. Recently, overexpression of ginseng-derived PgpPLAIIIβ was reported to be involved in the reduced level of lignin content in Arabidopsis and the mature xylem layer of poplar. The presence of lignin-polysaccharides renders cell walls recalcitrant for pulping and biofuel production. The tissue-specific regulation of lignin biosynthesis, without altering all xylem in plants, can be utilized usefully by keeping mechanical strength and resistance to various environmental stimuli. To identify another pPLAIII homolog from Arabidopsis, constitutively overexpressed AtpPLAIIIα was characterized for xylem lignification in two well-studied model plants, Arabidopsis and poplar. The characterization of gene function in annual and perennial plants with respect to lignin biosynthesis revealed the functional redundancy of less lignification via downregulation of lignin biosynthesis-related genes.

scholarly journals Increasing Lignin Accumulation in Arabidopsis and Poplar by Overexpressing a CCoAOMT Gene from Dove Tree (Davidia involucrata Baill.)

2020 ◽  
Author(s):  
Jian Li ◽  
Xiaomin Ji ◽  
XuJie Dong ◽  
Fuxiang Cao ◽  
Meng Li
Keyword(s):  
Lignin Content ◽  
Critical Role ◽  
Biological Significance ◽  
Lignin Biosynthesis ◽  
Compact Structure ◽  
Transgenic Lines ◽  
Lignin Composition ◽  
Lignin Accumulation ◽  
G Ratio ◽  
Em Gene

Rapid lignification occurring in the endocarp of dove tree results in the formation of a rigid and compact structure, which seriously hinders seed germination. A gene named DiCCoAOMT1, which encodes a hyperactive O-methyltransferase, was identified and thought to play a critical role in the process of endocarp lignification. In this study, the DiCCoAOMT1 gene was introduced into A. thaliana and poplar, respectively, to further verify its function. The lignin content was increased by 45% and 20% in the stems of transgenic A. thaliana and poplar lines, respectively. There was a positive correlation between the expression levels of DiCCoAOMT1 and lignin amount in transgenic lines. Furthermore, the shifts of lignin composition was indicated by the elevated S/G ratio in transgenic poplar lines. Lignin accumulation was promoted specifically in the phloem cells, and the cells in secondary xylem was thickened in transgenic plants. In addition, lengthened pods and elevated plant height, and elongated petioles and internodes were observed in transgenic A. thaliana and poplar lines, respectively. Taken together, our data indicated that an endocarp-specific DiCCoAOMT1 gene could effectively increase lignin accumulation and alter lignin composition in both herbs and woody plants, which provides new insights to understand the regulatory mechanism of lignin biosynthesis and the biological significance of lignification in specific tissues.

scholarly journals Molecular Characterization of a Date Palm Vascular Highway 1-Interacting Kinase (PdVIK) under Abiotic Stresses

Genes ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 568 ◽  
Author(s):  
Ibtisam Al-Harrasi ◽  
Himanshu V. Patankar ◽  
Rashid Al-Yahyai ◽  
Ramanjulu Sunkar ◽  
Pannaga Krishnamurthy ◽  
...  
Keyword(s):  
Salinity Tolerance ◽  
Abiotic Stresses ◽  
Date Palm ◽  
Functional Characterization ◽  
Abiotic Stress Response ◽  
Oxidative Stresses ◽  
Transgenic Lines ◽  
Tolerance To Salinity

The date palm (Khalas) is an extremophile plant that can adapt to various abiotic stresses including drought and salinity. Salinity tolerance is a complex trait controlled by numerous genes. Identification and functional characterization of salt-responsive genes from the date palm is fundamental to understand salinity tolerance at the molecular level in this plant species. In this study, a salt-inducible vascular highway 1-interacting kinase (PdVIK) that is a MAP kinase kinase kinase (MAPKKK) gene from the date palm, was functionally characterized using in vitro and in vivo strategies. PdVIK, one of the 597 kinases encoded by the date palm genome possesses an ankyrin repeat domain and a kinase domain. The recombinant PdVIK protein exhibited phosphotyrosine activity against myelin basic protein (MBP) substrate. Overexpression of PdVIK in yeast significantly improved its tolerance to salinity, LiCl, and oxidative stresses. Transgenic Arabidopsis seedlings overexpressing PdVIK displayed improved tolerance to salinity, osmotic, and oxidative stresses as assessed by root growth assay. The transgenic lines grown in the soil also displayed modulated salt response, compared to wild-type controls as evaluated by the overall plant growth and proline levels. Likewise, the transgenic lines exhibited drought tolerance by maintaining better relative water content (RWC) compared to non-transgenic control plants. Collectively, these results implicate the involvement of PdVIK in modulating the abiotic stress response of the date palm.

scholarly journals Identification and Functional Characterization of a new Sunflower Germacrene A Synthase (HaGAS3)

2010 ◽  
Vol 5 (5) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
Jens Göpfert ◽  
Anna-Katharina Bülow ◽  
Otmar Spring
Keyword(s):  
Sesquiterpene Lactones ◽  
Glandular Trichomes ◽  
Functional Characterization ◽  
Plant Tissues ◽  
Rt Pcr ◽  
Plant Organs ◽  
Reverse Transcription Pcr ◽  
Engineered Yeast

Sesquiterpenes and sesquiterpene lactones are major natural compounds found in linear and capitate glandular trichomes of sunflower, Helianthus annuus L. In addition to two recently identified germacrene A synthases HaGAS1 and HaGAS2, found in capitate trichome gland cells, reverse transcription-PCR experiments have now allowed identification of a third enzyme of this type, HaGAS3. Its cDNA sequence was established and its functional characterization as a germacrene A synthase was achieved through in vitro expression in engineered yeast, and by GC-MS experiments. PCR and RT-PCR experiments with cDNA from different plant organs revealed that the new enzyme is expressed independently from the other two. While these latter two were expressed in plant organs bearing capitate glandular trichomes and in roots, the new enzyme occurred in plant tissues not linked to the presence of specific trichomes (for example, cotyledons), and was absent in roots. The experiments show that independently regulated pathways for the first cyclic sesquiterpene, germacrene A, are present in sunflower.

Transgenic down-regulation of caffeic acid O-methyltransferase (COMT) led to improved digestibility in tall fescue (Festuca arundinacea)

2004 ◽  
Vol 31 (3) ◽  
pp. 235 ◽  
Author(s):  
Lei Chen ◽  
Chung-Kyoon Auh ◽  
Paul Dowling ◽  
Jeremey Bell ◽  
Deane Lehmann ◽  
...  
Keyword(s):  
Caffeic Acid ◽  
Tall Fescue ◽  
Festuca Arundinacea ◽  
Lignin Content ◽  
Microprojectile Bombardment ◽  
Lignin Biosynthesis ◽  
Suspension Cells ◽  
Dry Matter Digestibility ◽  
Transgenic Lines ◽  
Transgenic Tall Fescue

Dry matter digestibility is one of the most important characteristics of forage. The major constraint on ruminant digestion of forage cell walls is lignin. Sequences of cDNA encoding a key lignin biosynthetic enzyme, caffeic acid O-methyltransferase (COMT), was cloned from the widely grown monocot forage species tall fescue (Festuca arundinacea Schreb.). Enzymatic properties of recombinant COMT protein expressed in E. coli were determined using six substrates. The preferred substrates for tall fescue recombinant COMT were 5-hydroxyferulic acid and caffeoyl aldehyde. Transgenic tall fescue plants carrying either sense or antisense COMT gene constructs were obtained by microprojectile bombardment of single-genotype-derived embryogenic suspension cells. Consistent and closely related molecular and biochemical data demonstrated that two co-suppressed transgenic lines were down-regulated in their lignin biosynthesis. These COMT down-regulated transgenic tall fescue plants showed substantially reduced levels of transcripts, significantly reduced enzymatic activities, significantly decreased lignin content, apparently altered lignin composition and significantly increased (9.8-10.8%) digestibility.

scholarly journals LACCASE14 is required for the deposition of guaiacyl lignin and affects cell wall digestibility in poplar

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Shifei Qin ◽  
Chunfen Fan ◽  
Xiaohong Li ◽  
Yi Li ◽  
Jian Hu ◽  
...  
Keyword(s):  
Cell Wall ◽  
Genetic Manipulation ◽  
Lignin Content ◽  
Biomass Conversion ◽  
Enzymatic Saccharification ◽  
Lignin Biosynthesis ◽  
Populus Tomentosa ◽  
Wall Structure ◽  
Biomass Saccharification

Abstract Background The recalcitrance of lignocellulosic biomass provided technical and economic challenges in the current biomass conversion processes. Lignin is considered as a crucial recalcitrance component in biomass utilization. An in-depth understanding of lignin biosynthesis can provide clues to overcoming the recalcitrance. Laccases are believed to play a role in the oxidation of lignin monomers, leading to the formation of higher-order lignin. In plants, functions of only a few laccases have been evaluated, so little is known about the effect of laccases on cell wall structure and biomass saccharification. Results In this study, we screened a gain-of-function mutant with a significant increase in lignin content from Arabidopsis mutant lines overexpressing a full-length poplar cDNA library. Further analysis confirmed that a Chinese white poplar (Populus tomentosa) laccase gene PtoLAC14 was inserted into the mutant, and PtoLAC14 could functionally complement the Arabidopsis lac4 mutant. Overexpression of PtoLAC14 promoted the lignification of poplar and reduced the proportion of syringyl/guaiacyl. In contrast, the CRISPR/Cas9-generated mutation of PtLAC14 results in increased the syringyl/guaiacyl ratios, which led to integrated enhancement on biomass enzymatic saccharification. Notably, the recombinant PtoLAC14 protein showed higher oxidized efficiency to coniferyl alcohol (precursor of guaiacyl unit) in vitro. Conclusions This study shows that PtoLAC14 plays an important role in the oxidation of guaiacyl deposition on cell wall. The reduced recalcitrance of the PtoLAC14-KO lines suggests that PtoLAC14 is an elite target for cell wall engineering, and genetic manipulation of this gene will facilitate the utilization of lignocellulose.

scholarly journals Chitinases of Trichoderma atroviride Induce Scab Resistance and Some Metabolic Changes in Two Cultivars of Apple

2003 ◽  
Vol 93 (12) ◽  
pp. 1496-1504 ◽  
Author(s):  
M. Faize ◽  
M. Malnoy ◽  
F. Dupuis ◽  
M. Chevalier ◽  
L. Parisi ◽  
...  
Keyword(s):  
Defense Mechanism ◽  
Lignin Content ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Scab Resistance ◽  
Trichoderma Atroviride ◽  
Transgenic Lines ◽  
Race 1 ◽  
The Common

This study reports the combination of a transgene-mediated defense mechanism with a conventionally bred resistance in order to improve apple scab resistance. Two cultivars of apple (Galaxy, scab-susceptible, and Ariane, carrying the Vf resistance gene) were transformed with endochitinase and exochitinase genes derived from the biocontrol fungus Trichoderma atroviride. The obtained transgenic lines were analyzed for the expression of both genes and resistance to two races of the pathogen Venturia inaequalis: the common race 1 and race 6 which overcomes the resistance conferred by the Vf gene. A negative correlation between growth of transgenic lines and endochitinase activity was observed. Reduced growth appeared to be associated with high lignin content and high peroxidase as well as glucanase activity, suggesting that endochitinase activity may disturb the metabolism of the plant. Scab inoculation with races 1 and 6 performed in a growth chamber on 14 lines of normal vigor identified 6 lines with significantly enhanced resistance. Ten lines with reduced vigor were tested in vitro with a bioassay on rooted shoots. All lines expressing high endochitinase activity exhibited a significant reduction of scab symptoms.

scholarly journals Identification and Characterization of the CCoAOMT Gene Family in Apple, Chinese White Pear, and Peach

2021 ◽  
pp. 1-12
Author(s):  
Leli Li ◽  
Shutian Tao ◽  
Huangwei Zhang ◽  
Weijian Huang ◽  
Jim M. Dunwell ◽  
...  
Keyword(s):  
Gene Family ◽  
Prunus Persica ◽  
Lignin Content ◽  
Expression Patterns ◽  
Lignin Biosynthesis ◽  
Pathogenic Fungi ◽  
Development Stage ◽  
Chinese White ◽  
Main Components

Lignin is one of the main components of plant cell walls, which provides mechanical support for plants and also contributes to resisting against plant pathogenic fungi. In the fruit industry, the lignin content can affect the quality of fruit. The biosynthesis of lignin involves a variety of enzymes, of which caffeoyl-CoA 3-O-methyltransferase (CCoAOMT) is a class of methyltransferases that plays an essential role in lignin biosynthesis. Studies have been conducted on the CCoAOMT gene family in several species, including arabidopsis (Arabidopsis thaliana), black poplar (Populus nigra), and cotton (Gossypium hirsutum). Still, there is relatively little research on this gene family in the Rosaceae. In this study, we used bioinformatics to identify and characterize the CCoAOMT gene family in apple (Malus domestica), chinese white pear (Pyrus bretschneideri), and peach (Prunus persica). In total, 35 CCoAOMT genes were identified in the three Rosaceae species: 8 from chinese white pear, 12 from apple, and 15 from peach. By using structure analysis and collinearity analysis, we found 12 conserved motifs and 12 pairs of CCoAOMT genes with collinearity. In the phylogenetic tree, the gene family was mainly divided into two groups. The genes had different expression patterns during the growth and development stage of fruit, a finding that is consistent with the pattern of lignin accumulation. This study will be beneficial for further study of CCoAOMT genes.

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