Characterization of Galacturonosyl Transferase Genes rgtA, rgtB, rgtC, rgtD, and rgtE Responsible for Lipopolysaccharide Synthesis in Nitrogen-fixing Endosymbiont Rhizobium leguminosarum

Brown, Dean R.; Forsberg, Lennart S.; Kannenberg, Elmar L.; Carlson, Russell W.

doi:10.1074/jbc.m111.311571

Cited by 9 publications

(13 citation statements)

References 37 publications

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“…A chitinase-like protein was overexpressed in the Arabidopsis hot2 mutant, which has excellent tolerance to heat, salt, and drought stresses [32]. Galacturonosyl transferase is the core element of pectin biosynthesis in the plant cell wall, indicating that upregulation of alpha-1,4-galacturonosyltransferase could adjust the osmotic potential via alterations to the plant cell wall [33]. Significant upregulation of genes encoding beta-amylase, which are involved in starch and sucrose metabolism (ko00500) was also noted.…”

Section: Discussionmentioning

confidence: 99%

Identifying resurrection genes through the differentially expressed genes between Selaginella tamariscina (Beauv.) spring and Selaginella moellendorffii Hieron under drought stress

Zhang

Sun

et al. 2019

PLoS ONE

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Selaginella tamariscina (Beauv.) spring, a primitive vascular resurrection plant, can survive extreme drought and recover when water becomes available. To identify drought-inducible genes and to clarify the molecular mechanism of drought tolerance, a comparative transcriptional pattern analysis was conducted between S. tamariscina and Selaginella moellendorffii Hieron (drought sensitive). 133 drought related genes were identified, including 72 functional genes and 61 regulatory genes. And several drought responsive reactions, such as antioxidant activity, osmotic balance, cuticle defense and signal transduction were highlighted in S. tamariscina under drought. Notably, besides peroxidase, catalase and L-ascorbate oxidase genes, DEGs associated with phenylalanine metabolism and polyamine catabolism could be alternative ways to enhance antioxidant ability in S. tamariscina. DEGs related to soluble carbohydrate metabolism, late embryogenesis abundant protein (LEA) and aquaporin protein (AQP) confirmed that osmotic adjustment could resist drought during desiccation. DEGs involved in xyloglucan metabolic process, pectin metabolic process and cutin biosynthesis may also contribute to drought tolerance of S. tamariscina by cuticle defense. Drought-responsive genes encoding protein kinases, calcium sensors, transcription factors (TFs) and plant hormones also help to drought resistance of S. tamariscina. The preliminary validation experiments were performed and the results were consistent with our hypothetical integrated regulatory network. The results of this study provide candidate resurrection genes and an integrated regulatory network for further studies on the molecular mechanisms of stress tolerance in S. tamariscina.

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Section: Discussionmentioning

confidence: 99%

Identifying resurrection genes through the differentially expressed genes between Selaginella tamariscina (Beauv.) spring and Selaginella moellendorffii Hieron under drought stress

Zhang

Sun

et al. 2019

PLoS ONE

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“…Despite the apparent up-regulation of PagL in R. etli bacteroids, the modification catalyzed by PagL does not appear to be essential for nodule development and nitrogen-fixation. The 3- O deacylation reaction, like other lipid A modification reactions, could play a role in protecting bacterial symbionts from the plant immune response during pathogenic infections [18, 36, 48]. PagL activity in Gram-negative pathogens has been linked to an increase in resistance to antimicrobial peptides [49].…”

Section: Discussionmentioning

confidence: 99%

“…The resulting lipid A intermediate, Kdo 2 -lipid IV A intermediate is then processed by enzymes that are absent in E. coli . The R. etli lipid A modification enzymes include a 4′-phosphatase (LpxF) [12], a 1-phosphatase (LpxE) [13], a C28-specific long-chain acyltransferase (LpxXL) [14, 15], a galacturonosyltransferase (RgtD) [16–18], a lipid A oxidase (LpxQ) [19, 20], and an unidentified 3- O -deacylase [21]. …”

Section: Introductionmentioning

confidence: 99%

The calcium-stimulated lipid A 3-O deacylase from Rhizobium etli is not essential for plant nodulation

Sohlenkamp

Raetz

Ingram

2013

Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biolog

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The lipid A component of lipopolysaccharide from the nitrogen-fixing plant endosymbiont, Rhizobium etli, is structurally very different from that found in most enteric bacteria. The lipid A from free-living R. etli is structurally heterogeneous and exists as a mixture of species which are either pentaacylated or tetraacylated. In contrast, the lipid A from R. etli bacteroids is reported to consist exclusively of tetraacylated lipid A species. The tetraacylated lipid A species in both cases lack a β-hydroxymyristoyl chain at the 3-position of lipid A. Here, we show that the lipid A modification enzyme responsible for 3-O deacylation in R. etli is a homolog of the PagL protein originally described in Salmonella enterica sv. Typhimurium. In contrast to the PagL proteins described from other species, R. etli PagL displays a calcium dependency. To determine the importance of the lipid A modification catalyzed by PagL, we isolated and characterized a R. etli mutant deficient in the pagL gene. Mass spectrometric analysis confirmed that the mutant strain was exclusively tetraacylated and radiochemical analysis revealed that 3-O deacylase activity was absent in membranes prepared from the mutant. The R. etli mutant was not impaired in its ability to form nitrogen-fixing nodules on Phaseolus vulgaris but it displayed slower nodulation kinetics relative to the wild-type strain. The lipid A modification catalyzed by R. etli PagL, therefore, is not required for nodulation but may play other roles such as protecting bacterial endosymbionts from plant immune responses during infection.

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“…In Rhizobia, the phosphatases LpxE and LpxF dephosphorylate the 1 and 4 positions, respectively, of lipid A at the periplasmic surface of the IM (Karbarz et al, 2003;Wang et al, 2006). Sugars are then added to the 1 and 4 positions by the glycosyltransferases RgtF and RgtD, respectively, before the transport of mature LPS molecules to the OM (Brown et al, 2012(Brown et al, , 2013. NA1000 harbors a gene (CCNA_03113) with similarity to LpxE, but none with similarity to LpxF, raising the possibility that CtpA substitutes for LpxF.…”

Section: Ctpa Is Required For Wild-type Lipid a Structure And Abundancementioning

confidence: 99%

Caulobacter requires anionic sphingolipids and deactivation of fur to lose lipid A

Zik

Yoon

Guan

et al. 2022

Preprint

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Lipid A, the membrane-anchored portion of lipopolysaccharide, is an essential component of the outer membrane (OM) of nearly all Gram-negative bacteria. Here, we identify regulatory and structural factors that together permit Caulobacter crescentus to eliminate lipid A from its OM. Mutations in the ferric uptake regulator fur allow Caulobacter to survive in the absence of either LpxC, which catalyzes an early step of lipid A synthesis, or CtpA, a tyrosine phosphatase homolog which we find is needed for wild-type lipid A structure and abundance. Alterations in Fur-regulated processes, rather than iron status per se, underlie the ability to eliminate lipid A. Fitness of lipid A-deficient Caulobacter requires a previously uncharacterized anionic sphingolipid, ceramide phosphoglycerate (CPG), which also mediates sensitivity to the antibiotic colistin. Our results demonstrate that, in an altered regulatory landscape, anionic sphingolipids can support the integrity of a lipid A-deficient OM.

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Characterization of Galacturonosyl Transferase Genes rgtA, rgtB, rgtC, rgtD, and rgtE Responsible for Lipopolysaccharide Synthesis in Nitrogen-fixing Endosymbiont Rhizobium leguminosarum

Cited by 9 publications

References 37 publications

Identifying resurrection genes through the differentially expressed genes between Selaginella tamariscina (Beauv.) spring and Selaginella moellendorffii Hieron under drought stress

Identifying resurrection genes through the differentially expressed genes between Selaginella tamariscina (Beauv.) spring and Selaginella moellendorffii Hieron under drought stress

The calcium-stimulated lipid A 3-O deacylase from Rhizobium etli is not essential for plant nodulation

Caulobacter requires anionic sphingolipids and deactivation of fur to lose lipid A

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