N-Acetylglucosamine-1-P Uridylyltransferase 1 and 2 Are Required for Gametogenesis and Embryo Development in Arabidopsis thaliana

Chen, Ya-Huei; Shen, Hwei-Ling; Hsu, Pei-Jung; Hwang, San‐Gwang; Cheng, Wei-Chih

doi:10.1093/pcp/pcu127

Cited by 21 publications

(40 citation statements)

References 47 publications

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“…In plants, defects in the enzymes involved in de novo UDP‐GlcNAc synthesis severely impact growth and development[11,16,17]. We demonstrated the significant function of AtGNK for UDP‐GlcNAc synthesis; however, we did not observe morphological changes or growth defects in the atgnk mutant compared with the wild type, which was most likely because of a sufficient supply of UDP‐GlcNAc from the de novo synthesis pathway under our growth conditions.…”

Section: Discussionmentioning

confidence: 59%

Identification of anN‐acetylglucosamine kinase essential for UDP‐N‐acetylglucosamine salvage synthesis inArabidopsis

et al. 2015

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a b s t r a c tUridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) donates GlcNAc for various glycans and glycoconjugates. We previously found that GlcNAc supplementation increases the UDP-GlcNAc content in Arabidopsis; however, the metabolic pathway was undefined. Here, we show that the homolog of human GlcNAc kinase (GNK) is conserved in land plants. Enzymatic assays of the Arabidopsis homologous protein (AtGNK) revealed kinase activity that was highly specific for GlcNAc. We also demonstrate the role of AtGNK in plants by using its knockout mutant, which presents lower UDP-GlcNAc contents and is insensitive to GlcNAc supplementation. Moreover, our results demonstrate the presence of a GlcNAc salvage pathway in plants.

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Section: Discussionmentioning

confidence: 59%

Identification of anN‐acetylglucosamine kinase essential for UDP‐N‐acetylglucosamine salvage synthesis inArabidopsis

et al. 2015

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“…The reproductive abilities of transgenic plants were also compromised in studies of mutants of some other enzymes involved in nucleotide sugar synthesis, e.g. UDP-N-acetylglucosamine pyrophosphorylase (Chen et al, 2014) and CMP-3-deoxy-D-manno-octulosonic acid synthetase (Kobayashi et al, 2011). Whereas all these studies underlined the importance of nucleotide sugars for plant reproduction, other more refined approaches are needed to define physiological roles of the UDP-sugar producing pyrophosphorylases.…”

Section: Discussionmentioning

confidence: 99%

Identification and characterization of inhibitors of UDP‐glucose and UDP‐sugar pyrophosphorylases for in vivo studies

2017

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Identification and characterization of inhibitors of UDP-glucose and UDP-sugar pyrophosphorylases for in vivo studies.The Plant Journal, 90 (6) SUMMARY UDP-sugars serve as ultimate precursors in hundreds of glycosylation reactions (e.g. for protein and lipid glycosylation, synthesis of sucrose, cell wall polysaccharides, etc.), underlying an important role of UDPsugar-producing enzymes in cellular metabolism. However, genetic studies on mechanisms of UDP-sugar formation were frequently hampered by reproductive impairment of the resulting mutants, making it difficult to assess an in vivo role of a given enzyme. Here, a chemical library containing 17 500 compounds was separately screened against purified UDP-glucose pyrophosphorylase (UGPase) and UDP-sugar pyrophosphorylase (USPase), both enzymes representing the primary mechanisms of UDP-sugar formation. Several compounds have been identified which, at 50 lM, exerted at least 50% inhibition of the pyrophosphorylase activity. In all cases, both UGPase and USPase activities were inhibited, probably reflecting common structural features of active sites of these enzymes. One of these compounds (cmp #6), a salicylamide derivative, was found as effective inhibitor of Arabidopsis pollen germination and Arabidopsis cell culture growth. Hit optimization on cmp #6 yielded two analogs (cmp #6D and cmp #6D2), which acted as uncompetitive inhibitors against both UGPase and USPase, and were strong inhibitors in the pollen test, with apparent inhibition constants of less than 1 lM. Their effects on pollen germination were relieved by addition of UDPglucose and UDP-galactose, suggesting that the inhibitors targeted UDP-sugar formation. The results suggest that cmp #6 and its analogs may represent useful tools to study in vivo roles of the pyrophosphorylases, helping to overcome the limitations of genetic approaches.

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“…Since the impact of NO on plant metabolism is related to its concentration being precisely regulated by the plant, depending on its abundance NO may provoke opposite effects under physiological and stress conditions [ 23 , 50 ]. In this study we reported how potato leaves from the same genotypes challenged with pathogens of different lifestyles, e.g.…”

Section: Discussionmentioning

confidence: 99%

Contrasting Regulation of NO and ROS in Potato Defense-Associated Metabolism in Response to Pathogens of Different Lifestyles

Floryszak‐Wieczorek

Arasimowicz‐Jelonek

2016

PLoS ONE

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Our research provides new insights into how the low and steady-state levels of nitric oxide (NO) and reactive oxygen species (ROS) in potato leaves are altered after the challenge with the hemibiotroph Phytophthora infestans or the necrotroph Botrytis cinerea, with the subsequent rapid and invader-dependent modification of defense responses with opposite effects. Mainly in the avirulent (avr) P. infestans–potato system, NO well balanced with the superoxide level was tuned with a battery of SA-dependent defense genes, leading to the establishment of the hypersensitive response (HR) successfully arresting the pathogen. Relatively high levels of S-nitrosoglutathione and S-nitrosothiols concentrated in the main vein of potato leaves indicated the mobile function of these compounds as a reservoir of NO bioactivity. In contrast, low-level production of NO and ROS during virulent (vr) P. infestans-potato interactions might be crucial in the delayed up-regulation of PR-1 and PR-3 genes and compromised resistance to the hemibiotrophic pathogen. In turn, B. cinerea triggered huge NO overproduction and governed inhibition of superoxide production by blunting NADPH oxidase. Nevertheless, a relatively high level of H2O2 was found owing to the germin-like activity in cooperation with NO-mediated HR-like cell death in potato genotypes favorable to the necrotrophic pathogen. Moreover, B. cinerea not only provoked cell death, but also modulated the host redox milieu by boosting protein nitration, which attenuated SA production but not SA-dependent defense gene expression. Finally, based on obtained data the organismal cost of having machinery for HR in plant resistance to biotrophs is also discussed, while emphasizing new efforts to identify other components of the NO/ROS cell death pathway and improve plant protection against pathogens of different lifestyles.

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N-Acetylglucosamine-1-P Uridylyltransferase 1 and 2 Are Required for Gametogenesis and Embryo Development in Arabidopsis thaliana

Cited by 21 publications

References 47 publications

Identification of anN‐acetylglucosamine kinase essential for UDP‐N‐acetylglucosamine salvage synthesis inArabidopsis

Identification of anN‐acetylglucosamine kinase essential for UDP‐N‐acetylglucosamine salvage synthesis inArabidopsis

Identification and characterization of inhibitors of UDP‐glucose and UDP‐sugar pyrophosphorylases for in vivo studies

Contrasting Regulation of NO and ROS in Potato Defense-Associated Metabolism in Response to Pathogens of Different Lifestyles

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