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. 2022 Feb 10:12:802424.
doi: 10.3389/fpls.2021.802424. eCollection 2021.

Forgotten Actors: Glycoside Hydrolases During Elongation Growth of Maize Primary Root

Alsu Nazipova  1 , Oleg Gorshkov  1 , Elena Eneyskaya  2 , Natalia Petrova  1 , Anna Kulminskaya  2   3 , Tatyana Gorshkova  1 , Liudmila Kozlova  1
Affiliations

Forgotten Actors: Glycoside Hydrolases During Elongation Growth of Maize Primary Root

Alsu Nazipova et al. Front Plant Sci. .

Abstract

Plant cell enlargement is coupled to dynamic changes in cell wall composition and properties. Such rearrangements are provided, besides the differential synthesis of individual cell wall components, by enzymes that modify polysaccharides in muro. To reveal enzymes that may contribute to these modifications and relate them to stages of elongation growth in grasses, we carried out a transcriptomic study of five zones of the primary maize root. In the initiation of elongation, significant changes occur with xyloglucan: once synthesized in the meristem, it can be linked to other polysaccharides through the action of hetero-specific xyloglucan endotransglycosidases, whose expression boosts at this stage. Later, genes for xyloglucan hydrolases are upregulated. Two different sets of enzymes capable of modifying glucuronoarabinoxylans, mainly bifunctional α-arabinofuranosidases/β-xylosidases and β-xylanases, are expressed in the maize root to treat the xylans of primary and secondary cell walls, respectively. The first set is highly pronounced in the stage of active elongation, while the second is at elongation termination. Genes encoding several glycoside hydrolases that are able to degrade mixed-linkage glucan are downregulated specifically at the active elongation. It indicates the significance of mixed-linkage glucans for the cell elongation process. The possibility that many glycoside hydrolases act as transglycosylases in muro is discussed.

Keywords: RNA-seq; cell wall; elongation (growth); glycoside hydrolase; maize (Zea mays L.); root.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Structure of matrix polysaccharides typical for primary cell walls and enzyme families whose members catalyze the cleavage or modification of glycosidic linkages indicated by arrows. The symbolic representation of monosaccharides is according to GlycoPedia (Pérez, 2014) https://www.glycopedia.eu. GH, glycoside hydrolase.
FIGURE 2
FIGURE 2
Scheme of maize root sampling for transcriptome and proteome (Marcon et al., 2015) analyses and four clusters of GH transcript abundance obtained by cluster analysis. The dot painting indicates maize root zones that were not used for analyses in this study.
FIGURE 3
FIGURE 3
Expression of maize genes encoding putative GH1 and GH3 β-D-glucosidases in maize roots and phylogenetic analysis of plant GH3 family members. (A) The level of transcripts (TGR, red-blue heat map) and abundance of corresponding protein (averaged and normalized total spectral counts (Marcon et al., 2015, red-green heat map) of genes encoding putative β-D-glucosidases of GH1 and GH3 protein families in analyzed zones of maize roots. Heat map color-coding was applied to each protein family separately. Genes with expression values below 100 in all the studied samples are not shown. TGR values are sorted from maximum to minimum within each cluster. Maize genes that co-expressed with primary and secondary cell wall cellulose-synthases, and with the XyG backbone synthase are given in blue, red, and green, respectively. Maize GH1 gene names are given according to Gómez-Anduro et al. (2011). ZmEXG1 is named after Kim et al. (2000). Cap, root cap; Mer, meristem; eElong, early elongation zone; Elong, zone of active elongation; lateElong, zone of late elongation before root hair initiation; RH, root hair zone; aa, amino acids; no data, no corresponding peptides were found by Marcon et al. (2015) proteomic analysis. (B) The unrooted maximum likelihood phylogenetic tree of plant GH3 members. Maize expressed genes are given in black, and unexpressed (TGR values lower than 16 in all the analyzed root samples) in gray, Arabidopsis thaliana genes in red, and barley in blue (only genes encoding enzymes with characterized enzymatic activity are shown (Hrmova et al., 1996; Hrmova and Fincher, 1997; Lee et al., 2003), Brachypodium distachyon BdBGLC1 (Bd1g08550) (Rubianes et al., 2019) is given in purple. The A. thaliana gene names follow Minic et al. (2004) for the BXL clade and follow Sampedro et al. (2017) for the ExoI clade. Numbers indicate ultrafast bootstrap support values for some branches.
FIGURE 4
FIGURE 4
Expression of maize genes encoding putative GH35 β-D-galactosidases in maize roots and phylogenetic analysis of plant GH35 family. (A) The level of transcripts (TGR, red-blue heat map) and abundance of corresponding proteins (averaged and normalized total spectral counts (Marcon et al., 2015), red-green heat map) of genes encoding putative β-D-galactosidases of the GH35 protein family in various zones of maize roots. Genes with expression values below 100 in all the studied samples are not shown. TGR values are sorted from maximum to minimum within each cluster. Maize genes co-expressed with primary and secondary cell wall cellulose-synthases, and with the XyG backbone synthase are given in blue, red, and green, respectively. XyG, xyloglucan; Gal, galactose; aa, amino acids; Cap, root cap; Mer, meristem; eElong, early elongation zone; Elong, zone of active elongation; lateElong, zone of late elongation before root hair initiation; RH, root hair zone; no data, no corresponding peptides were found by Marcon et al. (2015) proteomic analysis. (B) Unrooted maximum likelihood phylogenetic tree of GH35 protein family members. Maize expressed genes are given in black, and unexpressed (TGR values lower than 16 in all the analyzed root samples) in gray, Arabidopsis thaliana genes in red, flax LusBGAL (Roach et al., 2011) in blue, and radish RsBGAL1 (Kotake et al., 2005) in green. Arabidopsis gene names follow Chandrasekar and van der Hoorn (2016). HvExoI was used as outgroup, and branch length was shortened. Numbers indicate ultrafast bootstrap support values for some branches.
FIGURE 5
FIGURE 5
Expression of maize genes encoding putative β-D-xylosidases, xylanases, and α-L-arabinofuranosidases of the GH3, GH10, and GH51 families in maize roots and phylogenetic analysis of plant GH10 family. (A) The level of transcripts (TGR, red-blue heat map) and abundance of corresponding proteins (averaged and normalized total spectral counts (Marcon et al., 2015), red-green heat map) of genes encoding putative β-D-xylosidases, xylanases, and α-L-arabinofuranosidases in various zones of maize roots. Genes with expression values below 100 in all the studied samples are not shown. TGR values are sorted from maximum to minimum within each cluster. Maize genes co-expressed with primary and secondary cell wall cellulose-synthases are given in blue and red, respectively. Maize gene names for GH10 follow Hu et al. (2020). Maize gene names for GH51 follow Kozlova et al. (2015). Cap, root cap; Mer, meristem; eElong, early elongation zone; Elong, zone of active elongation; lateElong, zone of late elongation before root hair initiation; RH, root hair zone; aa, amino acids; no data, no corresponding peptides were found in any of the studied samples. (B) Unrooted maximum likelihood phylogenetic dendrogram of plant GH10 family members. Maize expressed genes are given in black, and unexpressed (TGR values lower than 16 in all the analyzed root samples) in gray, Arabidopsis thaliana in red, poplar (Derba-Maceluch et al., 2015), rice (Tu et al., 2020), and papaya (Johnston et al., 2013) genes are given in green, pink, and purple, respectively. Arabidopsis thaliana gene names follow Suzuki et al. (2002), and maize gene names follow Hu et al. (2020). Numbers indicate ultrafast bootstrap support values.
FIGURE 6
FIGURE 6
Expression of maize genes encoding putative xyloglucan endotransglucosylases/hydrolases (XTHs) of GH16 in maize roots. The level of transcripts (TGR, red-blue heat map) and abundance of corresponding proteins (averaged and normalized total spectral counts (Marcon et al., 2015), red-green heat map) of genes encoding putative XyG endotransglycosylases/hydrolases of the GH16 protein family in various zones of maize roots. Genes with expression values below 100 in all the studied samples are not shown. TGR values are sorted from maximum to minimum within each cluster. Maize genes co-expressed with primary and secondary cell wall cellulose-synthases, and the XyG backbone synthase are labeled in blue, red, and green, respectively. XyG, xyloglucan; MLG, mixed-linkage glucan; SCW, secondary cell wall, Cap, root cap; Mer, meristem; eElong, early elongation zone; Elong, zone of active elongation; lateElong, zone of late elongation before root hair initiation; RH, root hair zone; no data, no corresponding peptides were found by Marcon et al. (2015) proteomics analysis.
FIGURE 7
FIGURE 7
Unrooted maximum likelihood phylogenetic analysis of the plant GH16 family. Maize genes are given in black font for expressed genes and gray for those having TGR values lower than 16 in all the analyzed root samples, and Arabidopsis thaliana genes are given in red. Characterized XTHs of barley (Hrmova et al., 2007, 2009), Equisetum (Herburger et al., 2021), nasturtium (Crombie et al., 1998), and Brachypodium (Fan et al., 2018) are shown in purple, green, blue, and magenta, respectively. Numbers indicate ultrafast bootstrap support values for some branches.
FIGURE 8
FIGURE 8
Glycoside hydrolase activities in different zones of maize primary roots assayed in vitro and in situ. (A) The β-D-glucosidase, (B) β-D-galactosidase, β-D-xylosidase, α-L-arabinofuranosidase, xylanase, and 1,3;1,4-β-D-glucan endohydrolase activities measured in clarified homogenates. Values are given as mean (n = 3) ± SE. (C) The β-D-glucosidase and β-D-galactosidase activities of non-fixed maize primary root cross sections. Co, cortex; En, endodermis; Mx, metaxylem; Muc, mucilage; P, pith; Px, protoxylem; Rhd, rhizodermis. Bars are 50 μm.
FIGURE 9
FIGURE 9
Expression patterns of genes encoding enzymes that can mediate the synthesis, transglycosylation, and hydrolysis of cell wall matrix polysaccharides observed in growing maize roots. Only one gene representing a particular clade or family with the typical dynamics of transcript abundance is shown. The closest characterized homolog for each maize gene is indicated in parenthesis. All profiles are normalized to maximum. Cap, root cap; Mer, meristem; eElong, early elongation zone; Elong, elongation zone; lateElong, late elongation zone; PW, primary cell wall; SW, secondary cell wall.
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References

    1. Armenteros J. J. A., Tsirigos K. D., Sønderby C. K., Petersen T. N., Winther O., Brunak S., et al. (2019). SignalP 5.0 improves signal peptide predictions using deep neural networks. Nat. Biotechnol. 37 420–423. 10.1038/s41587-019-0036-z - DOI - PubMed
    1. Babcock G. D., Esen A. (1994). Substrate specificity of maize β-glucosidase. Plant Sci. 101 31–39. 10.1016/0168-9452(94)90162-7 - DOI
    1. Barnes W. J., Anderson C. T. (2018). Release, recycle, rebuild: cell-wall remodeling, autodegradation, and sugar salvage for new wall biosynthesis during plant development. Mol. Plant 11 31–46. 10.1016/j.molp.2017.08.011 - DOI - PubMed
    1. Benitez-Alfonso Y., Faulkner C., Pendle A., Miyashima S., Helariutta Y., Maule A. (2013). Symplastic intercellular connectivity regulates lateral root patterning. Dev. Cell 26 136–147. 10.1016/j.devcel.2013.06.010 - DOI - PubMed
    1. Benson D. A., Cavanaugh M., Clark K., Karsch-Mizrachi I., Lipman D. J., Ostell J., et al. (2012). GenBank. Nucleic Acids Res. 41 D36–D42. - PMC - PubMed

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