scholarly journals Functional Characterization of Hydroxyproline-O-Galactosyltransferases For Arabidopsis Arabinogalactan-Proteins synthesis

2021 ◽  
Author(s):  
Dasmeet Kaur ◽  
Michael A. Held ◽  
Mountain R. Smith ◽  
Allan M. Showalter
Keyword(s):  
Cell Wall ◽  
Seed Set ◽  
Pollen Viability ◽  
Expression Patterns ◽  
Functional Characterization ◽  
Primary Root ◽  
Arabinogalactan Proteins ◽  
Root Tip ◽  
Composition Analysis ◽  
Genetic Redundancy

Abstract Background: Arabinogalactan-proteins (AGPs) are structurally complex hydroxyproline-rich cell wall glycoproteins ubiquitous in the plant kingdom. AGPs biosynthesis involves a series of post-translational modifications including the addition of type II arabinogalactans to non-contiguous Hyp residues. To date, eight Hyp-galactosyltransferases (Hyp-GALTs; GALT2-GALT9) belonging to CAZy GT31, are known to catalyze the addition of the first galactose residues to AGP protein backbones and enable subsequent AGP glycosylation. The extent of genetic redundancy, however, remains to be elucidated for the Hyp-GALT gene family. Results: To examine their gene redundancy and functions, we generated various multiple gene knock-outs, including a triple mutant (galt5galt8galt9), two quadruple mutants (galt2galt5galt7galt8, galt2galt5galt7galt9), and one quintuple mutant (galt2galt5galt7galt8galt9), and comprehensively examined their biochemical and physiological phenotypes. The key findings include: AGP precipitations with β-Yariv reagent showed that GALT2, GALT5, GALT7, GALT8 and GALT9 act redundantly with respect to AGP glycosylation in cauline and rosette leaves, while the activity of GALT7, GALT8 and GALT9 dominate in the stem, silique and flowers. Monosaccharide composition analysis showed that galactose was decreased in the silique and root AGPs of the Hyp-GALT mutants. The AGP profile of 25789 quintuple mutant stems indicated changes in AGP profiles compared to WT. Additionally, TEM analysis of 25789 quintuple mutant stems indicated cell wall defects coincident with the observed developmental and growth impairment in these Hyp-GALT mutants. Correlated with expression patterns, GALT2, GALT5, GALT7, GALT8, and GALT9 display equal additive effects on insensitivity to β-Yariv-induced growth inhibition, silique length, plant height, and pollen viability. Interestingly, GALT7, GALT8, and GALT9 contributed more to primary root growth and root tip swelling under salt stress, whereas GALT2 and GALT5 played more important roles in seed morphology, germination defects and seed set. Pollen defects likely contributed to the reduced seed set in these mutants. Conclusion: Additive and pleiotropic effects of GALT2, GALT5, GALT7, GALT8 and GALT9 on vegetative and reproductive growth phenotypes were teased apart via generation of different combinations of Hyp-GALT knock-out mutants. Taken together, the generation of higher order Hyp-GALT mutants demonstrate the functional importance of AG polysaccharides decorating the AGPs with respect to various aspects of plant growth and development.

scholarly journals Functional characterization of hydroxyproline-O-galactosyltransferases for Arabidopsis arabinogalactan-protein synthesis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Dasmeet Kaur ◽  
Michael A. Held ◽  
Mountain R. Smith ◽  
Allan M. Showalter
Keyword(s):  
Cell Wall ◽  
Seed Set ◽  
Pollen Viability ◽  
Expression Patterns ◽  
Functional Characterization ◽  
Primary Root ◽  
Arabinogalactan Protein ◽  
Root Tip ◽  
Composition Analysis ◽  
Genetic Redundancy

Abstract Background Arabinogalactan-proteins (AGPs) are structurally complex hydroxyproline-rich cell wall glycoproteins ubiquitous in the plant kingdom. AGPs biosynthesis involves a series of post-translational modifications including the addition of type II arabinogalactans to non-contiguous Hyp residues. To date, eight Hyp-galactosyltransferases (Hyp-GALTs; GALT2-GALT9) belonging to CAZy GT31, are known to catalyze the addition of the first galactose residues to AGP protein backbones and enable subsequent AGP glycosylation. The extent of genetic redundancy, however, remains to be elucidated for the Hyp-GALT gene family. Results To examine their gene redundancy and functions, we generated various multiple gene knock-outs, including a triple mutant (galt5 galt8 galt9), two quadruple mutants (galt2 galt5 galt7 galt8, galt2 galt5 galt7 galt9), and one quintuple mutant (galt2 galt5 galt7 galt8 galt9), and comprehensively examined their biochemical and physiological phenotypes. The key findings include: AGP precipitations with β-Yariv reagent showed that GALT2, GALT5, GALT7, GALT8 and GALT9 act redundantly with respect to AGP glycosylation in cauline and rosette leaves, while the activity of GALT7, GALT8 and GALT9 dominate in the stem, silique and flowers. Monosaccharide composition analysis showed that galactose was decreased in the silique and root AGPs of the Hyp-GALT mutants. TEM analysis of 25789 quintuple mutant stems indicated cell wall defects coincident with the observed developmental and growth impairment in these Hyp-GALT mutants. Correlated with expression patterns, galt2, galt5, galt7, galt8, and galt9 display equal additive effects on insensitivity to β-Yariv-induced growth inhibition, silique length, plant height, and pollen viability. Interestingly, galt7, galt8, and galt9 contributed more to primary root growth and root tip swelling under salt stress, whereas galt2 and galt5 played more important roles in seed morphology, germination defects and seed set. Pollen defects likely contributed to the reduced seed set in these mutants. Conclusion Additive and pleiotropic effects of GALT2, GALT5, GALT7, GALT8 and GALT9 on vegetative and reproductive growth phenotypes were teased apart via generation of different combinations of Hyp-GALT knock-out mutants. Taken together, the generation of higher order Hyp-GALT mutants demonstrate the functional importance of AG polysaccharides decorating the AGPs with respect to various aspects of plant growth and development.

scholarly journals The Arabidopsis Root Tip (Phospho)Proteomes at Growth-Promoting versus Growth-Repressing Conditions Reveal Novel Root Growth Regulators

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1665
Author(s):  
Natalia Nikonorova ◽  
Evan Murphy ◽  
Cassio Flavio Fonseca de Lima ◽  
Shanshuo Zhu ◽  
Brigitte van de Cotte ◽  
...  
Keyword(s):  
Cell Wall ◽  
Root Growth ◽  
Growth Regulators ◽  
Growth Regulation ◽  
Phosphorylation Site ◽  
Primary Root ◽  
Root Tip ◽  
Arabidopsis Root ◽  
Growth Promoting ◽  
The Impact

Auxin plays a dual role in growth regulation and, depending on the tissue and concentration of the hormone, it can either promote or inhibit division and expansion processes in plants. Recent studies have revealed that, beyond transcriptional reprogramming, alternative auxin-controlled mechanisms regulate root growth. Here, we explored the impact of different concentrations of the synthetic auxin NAA that establish growth-promoting and -repressing conditions on the root tip proteome and phosphoproteome, generating a unique resource. From the phosphoproteome data, we pinpointed (novel) growth regulators, such as the RALF34-THE1 module. Our results, together with previously published studies, suggest that auxin, H+-ATPases, cell wall modifications and cell wall sensing receptor-like kinases are tightly embedded in a pathway regulating cell elongation. Furthermore, our study assigned a novel role to MKK2 as a regulator of primary root growth and a (potential) regulator of auxin biosynthesis and signalling, and suggests the importance of the MKK2 Thr31 phosphorylation site for growth regulation in the Arabidopsis root tip.

scholarly journals Genome-Wide Identification and Expression Profile Analysis of the Phospholipase C Gene Family in Wheat (Triticum aestivum L.)

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 885
Author(s):  
Xianguo Wang ◽  
Yang Liu ◽  
Zheng Li ◽  
Xiang Gao ◽  
Jian Dong ◽  
...  
Keyword(s):  
Gene Family ◽  
Phospholipase C ◽  
Profile Analysis ◽  
Expression Patterns ◽  
Functional Characterization ◽  
Primary Root ◽  
In Silico Analysis ◽  
Triticum Aestivum L ◽  
Stress Conditions ◽  
Phosphatase Domain

Phospholipid-hydrolyzing enzymes include members of the phospholipase C (PLC) family that play important roles in regulating plant growth and responding to stress. In the present study, a systematic in silico analysis of the wheat PLC gene family revealed a total of 26 wheat PLC genes (TaPLCs). Phylogenetic and sequence alignment analyses divided the wheat PLC genes into 2 subfamilies, TaPI-PLC (containing the typical X, Y, and C2 domains) and TaNPC (containing a phosphatase domain). TaPLC expression patterns differed among tissues, organs, and under abiotic stress conditions. The transcript levels of 8 TaPLC genes were validated through qPCR analyses. Most of the TaPLC genes were sensitive to salt stress and were up-regulated rapidly, and some were sensitive to low temperatures and drought. Overexpression of TaPI-PLC1-2B significantly improved resistance to salt and drought stress in Arabidopsis, and the primary root of P1-OE was significantly longer than that of the wild type under stress conditions. Our results not only provide comprehensive information for understanding the PLC gene family in wheat, but can also provide a solid foundation for functional characterization of the wheat PLC gene family.

scholarly journals Genome-wide identification and characterization of SnRK family genes in Brassica napus

2020 ◽  
Author(s):  
Weizhuo Zhu ◽  
Dezhi Wu ◽  
Lixi Jiang ◽  
Lingzhen Ye
Keyword(s):  
Brassica Napus ◽  
Abiotic Stresses ◽  
Expression Patterns ◽  
Functional Characterization ◽  
Composition Analysis ◽  
Distribution Analysis ◽  
Element Analysis ◽  
Genome Wide ◽  
Identification And Characterization

Abstract Background: Sucrose non-fermenting 1 related protein kinases (SnRK) play crucial roles in responding to biotic and abiotic stresses through activating protein phosphorylation pathways. However, little information of SnRK genes was available in Brassica napus, one of important oil crops. Recently, the released sequences of the reference genome of B.napus provide a good chance to perform genome-wide identification and characterization of BnSnRK gene family in the rapeseed.Results: Totally 114 SnRK genes distributed on 19 chromosomes were identified in the genome of B.napus and classified into three subfamilies on the basis of phylogenetic analysis and the domain types. According to gene structure and motif composition analysis, the BnSnRK sequences showed obvious divergence among three subfamilies. Gene duplication and synteny between the genomes of the rapeseed and Arabidopsis were also analyzed to provide insights into the evolutionary characteristics of BnSnRK family genes. Cis-element analysis revealed that BnSnRKs may response to diverse environmental stresses. Moreover, the expression patterns of BnSnRKs in various tissues and under diverse abiotic stresses were distinct difference. Besides, Single Nucleotide Polymorphisms (SNP) distribution analysis suggests the function disparity of BnSnRK family genes in different genotypes of the rapeseed.Conclusion: We examined genomic structures, evolution features, expression patterns and SNP distribution of 114 BnSnRKs. The results provide valuable information for functional characterization of BnSnRK genes in future studies.

scholarly journals Identification and Functional Characterization of Apple MdCKX5.2 in Root Development and Abiotic Stress Tolerance

Horticulturae ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 62
Author(s):  
Yang Liu ◽  
Xun Wang ◽  
Xiaofei Wang ◽  
Wensheng Gao ◽  
Chunxiang You
Keyword(s):  
Expression Analysis ◽  
Root Development ◽  
Expression Profiles ◽  
Abiotic Stress Tolerance ◽  
Expression Patterns ◽  
Functional Characterization ◽  
Primary Root ◽  
Cytokinin Oxidase ◽  
Lateral Root Development ◽  
Exogenous Cytokinin

Cytokinin oxidase/dehydrogenases (CKXs) are the key enzymes in cytokinin degradation and have been widely studied in model plants. Little is known about apple’s (Malus×domestica) CKX genes. Here, using genome-wide analysis, we identified 10 MdCKX genes in apple. The phylogenetics, chromosome locations, and genome structures were then tested. Expression analysis showed that MdCKX genes had different expression profiles in apple, pointing to the different roles. Meanwhile, relative expression analysis showed that these genes have different expression patterns in response to several exogenous cytokinin factors, including trans-zeatin (ZT), thidiazuron (TDZ), and N6-furfuryladenine (KT). Finally, we introduced the MdCKX5.2 gene into Arabidopsis to evaluate its functions, and the results suggested the transgenic Arabidopsis displayed phenotypes related to promoting primary root and lateral root development, response to exogenous ZT, and conferring to drought and salt tolerant. Taken together, our results provide insights on the possible application of the MdCKX5.2 gene for molecular breeding in apples.

scholarly journals In silico and expression analyses of fasciclin-like arabinogalactan proteins reveal functional conservation during embryo and seed development

2019 ◽  
Vol 32 (4) ◽  
pp. 353-370 ◽  
Author(s):  
Mário Costa ◽  
Ana Marta Pereira ◽  
Sara Cristina Pinto ◽  
Jessy Silva ◽  
Luís Gustavo Pereira ◽  
...  
Keyword(s):  
Cell Wall ◽  
Seed Development ◽  
Plant Cell Wall ◽  
Functional Organization ◽  
Sequence Similarity ◽  
Expression Patterns ◽  
Arabinogalactan Proteins ◽  
Cork Oak ◽  
Functional Domain ◽  
Functional Conservation

Key message The fasciclin-like arabinogalactan proteins organization into four groups is conserved and may be related to specific roles in developmental processes across angiosperms. Abstract Fasciclin-like arabinogalactan proteins (FLAs) are a subclass of arabinogalactan proteins (AGPs), which contain fasciclin-like domains in addition to typical AGP domains. FLAs are present across all embryophytes, and despite their low overall sequence similarity, conserved regions that define the fasciclin functional domain (FAS) have been identified, suggesting that the cell adhesion property is also conserved. FLAs in Arabidopsis have been organized into four subgroups according to the number and distribution of functional domains. Recent studies associated FLAs with cell wall-related processes where domain organization seemed to be related to functional roles. In Arabidopsis, FLAs containing a single FAS domain were found to be important for the integrity and elasticity of the plant cell wall matrix, and FLAs with two FAS domains and two AGP domains were found to be involved in maintaining proper cell expansion under salt stress conditions. The main purpose of the present work was to elucidate the expression pattern of selected FLA genes during embryo and seed development using RT-qPCR. AtFLA8 and AtFLA10, two Arabidopsis genes that stood out in previous microarray studies of embryo development, were further examined using promoter-driven gene reporter analyses. We also studied the expression of cork oak FLA genes and found that their expression partially parallels the expression patterns of the putative AtFLA orthologs. We propose that the functional organization of FLAs is conserved and may be related to fundamental aspects of embryogenesis and seed development across angiosperms. Phylogenetic studies were performed, and we show that the same basic four-subgroup organization described for Arabidopsis FLA gene classification is valid for most Arabidopsis FLA orthologs of several plant species, namely poplar, corn and cork oak.

scholarly journals The rice BZ1 locus is required for glycosylation of arabinogalactan proteins and galactolipid and plays a role in both mechanical strength and leaf color

2020 ◽  
Author(s):  
Sitong Liu ◽  
Yijun Tang ◽  
Nan Ruan ◽  
Zhengjun Dang ◽  
Yuwei Huang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Mechanical Strength ◽  
Agronomic Traits ◽  
Functional Characterization ◽  
Arabinogalactan Proteins ◽  
Lipid Profiling ◽  
Chloroplast Membrane ◽  
Rice Mutant ◽  
Altered Cell ◽  
Sugar Chains

Abstract Background: The cell wall and chloroplast are two fundamental structures determining plant mechanical strength and grain yield. Therefore, understanding mechanisms that improve plants’ ability to develop a robust cell wall and well-developed chloroplast is of utmost importance for agricultural activities. Results: In this study, we report the functional characterization of a novel rice mutant, brittle stem and zebra leaf (bz1), which displays altered cell wall composition and collapsed chloroplast membrane. Molecular and biochemical analysis revealed that BZ1 encodes a functional UDP-galactose/glucose epimerase (UGE) and is ubiquitously expressed with higher expression in stem and leaf tissues. Multiple techniques analyses, including immunoblots, immuno-gold, and cryogenic scanning electron microscopy, demonstrated a significantly impaired glycosylation of arabinogalactan proteins (AGPs) and disordered cellulose microfibril deposition in bz1. Lipid profiling assay showed that the amount of monogalactosyldiacylglycerols (MGDG), a major chloroplast membrane glycolipid, was significantly decreased in bz1. Taken together, these results strongly demonstrate that BZ1 participates in UDP-galactose supply for the sugar chains biosynthesis of AGPs and MGDG, which thereby, respectively, results in altered cell wall and abnormal chloroplast development. Due to inferior mechanical strength and reduced photosynthesis, bz1 plants displayed detrimental agronomic traits, whereas BZ1 overexpressing lines showed enhanced plant growth. Transcriptome analysis of stems and leaves further showed that numerous key genes involved in AGPs biosynthesis and photosynthesis metabolism were substantially suppressed in bz1.Conclusions: Our finding identifies BZ1 as a dual-targeting UGE protein for glycosylation of AGPs and MGDG and suggests a strategy for breeding robust elite crops.

scholarly journals Genome-Wide Analysis of Glycoside Hydrolase Family 35 Genes and Their Potential Roles in Cell Wall Development in Medicago truncatula

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1639
Author(s):  
Junfeng Yang ◽  
Qian Li ◽  
Wenxuan Du ◽  
Yu Yao ◽  
Guoan Shen ◽  
...  
Keyword(s):  
Cell Wall ◽  
Medicago Truncatula ◽  
Glycoside Hydrolase ◽  
Expression Patterns ◽  
Functional Characterization ◽  
Glycoside Hydrolase Family ◽  
Forage Crops ◽  
Specific Expression ◽  
Hydrolase Family ◽  
Expression Module

Plant β-galactosidases (BGAL) function in various cell wall biogeneses and modifications, and they belong to the glycoside hydrolase family. However, the roles of BGAL family members in Medicago truncatula cell wall remodeling remain unclear. In this study, a total of 25 MtBGAL members of the glycoside hydrolase gene family 35 were identified, and they were clustered into nine sub-families. Many cis-acting elements possibly related to MeJA and abscisic acid responses were identified in the promoter region of the MtBGAL genes. Transcript analyses showed that these MtBGAL genes exhibited distinct expression patterns in various tissues and developing stem internodes. Furthermore, a stem-specific expression module associated with cell wall metabolic pathways was identified by weighted correlation network analysis (WGCNA). In particular, MtBGAL1 and MtBGAL23 within the stem-specific expression module were highly expressed in mature stems. In addition, several genes involved in lignin, cellulose, hemicellulose and pectin pathways were co-expressed with MtBGAL1 and MtBGAL23. It was also found that MtBGAL1 and MtBGAL23 were localized to the cell wall at the subcellular level, indicating their roles in the modification of cell wall metabolites in Medicago. As a whole, these results will be useful for further functional characterization and utilization of BGAL genes in cell wall modifications aiming to improve the quality of legume forage crops.

scholarly journals Auxin-triggered changes in the Arabidopsis root tip (phospho)proteome reveal novel root growth regulators

2021 ◽  
Author(s):  
Natalia Nikonorova ◽  
Evan Murphy ◽  
Cassio Flavio Fonseca de Lima ◽  
Shanshuo Zhu ◽  
Brigitte van de Cotte ◽  
...  
Keyword(s):  
Cell Wall ◽  
Root Growth ◽  
Growth Regulators ◽  
Growth Regulation ◽  
Phosphorylation Site ◽  
Primary Root ◽  
Root Tip ◽  
Arabidopsis Root ◽  
Transcriptional Reprogramming ◽  
The Impact

ABSTRACTAuxin plays a dual role in growth regulation and, depending on the tissue and concentration of the hormone, it can either promote or inhibit division and expansion processes in plants. Recent studies revealed that, beyond transcriptional reprogramming, alternative auxin-controlled mechanisms regulate root growth. Here, we explored the impact of different auxin concentrations on the root tip proteome and phosphoproteome, generating a unique resource. From the phosphoproteome data we pinpointed (novel) growth regulators, such as the RALF34-THE1 module. Our results together with previously published studies suggest that auxin, H+-ATPases, cell wall modifications and cell wall sensing receptor-like kinases are tightly embedded in a pathway regulating cell elongation. Furthermore, our study assigned a novel role to MKK2 as a regulator of primary root growth and a (potential) regulator of auxin biosynthesis and signalling, and suggests the importance of the MKK2 Thr31phosphorylation site for growth regulation in theArabidopsisroot tip.ONE SENTENCE SUMMARYAn auxin-triggered Arabidopsis root tip (phospho)proteome reveals novel root growth regulators

scholarly journals Genome-wide identification and characterization of SnRK family genes in Brassica napus

2020 ◽  
Author(s):  
Weizhuo Zhu ◽  
Dezhi Wu ◽  
Lixi Jiang ◽  
Lingzhen Ye
Keyword(s):  
Brassica Napus ◽  
Abiotic Stresses ◽  
Expression Patterns ◽  
Functional Characterization ◽  
Composition Analysis ◽  
Distribution Analysis ◽  
Element Analysis ◽  
Genome Wide ◽  
Identification And Characterization

Abstract Background: Sucrose non-fermenting 1 related protein kinases (SnRK) play crucial roles in responding to biotic and abiotic stresses through activating protein phosphorylation pathways. However, little information of SnRK genes was available in Brassica napus, one of important oil crops. Recently, the released sequences of the reference genome of B.napus provide a good chance to perform genome-wide identification and characterization of BnSnRK gene family in the rapeseed.Results: Totally 114 SnRK genes distributed on 19 chromosomes were identified in the genome of B.napus and classified into three subfamilies on the basis of phylogenetic analysis and the domain types. According to gene structure and motif composition analysis, the BnSnRK sequences showed obvious divergence among three subfamilies. Gene duplication and synteny between the genomes of the rapeseed and Arabidopsis were also analyzed to provide insights into the evolutionary characteristics of BnSnRK family genes. Cis-element analysis revealed that BnSnRKs may response to diverse environmental stresses. Moreover, the expression patterns of BnSnRKs in various tissues and under diverse abiotic stresses were distinct difference. Besides, Single Nucleotide Polymorphisms (SNP) distribution analysis suggests the function disparity of BnSnRK family genes in different genotypes of the rapeseed.Conclusion: We examined genomic structures, evolution features, expression patterns and SNP distribution of 114 BnSnRKs. The results provide valuable information for functional characterization of BnSnRK genes in future studies.

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