Growth in rice cells requires de novo purine biosynthesis by the blast fungus Magnaporthe oryzae

Fernandez, Jessie; Yang, Kuan Ting; Cornwell, Kathryn M.; Wright, Janet; Wilson, Richard A.

doi:10.1038/srep02398

Cited by 48 publications

(64 citation statements)

References 31 publications

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“…Based on these results, we hypothesized that the host defense response was not the major reason for the restricted growth of invasion by M. oryzae hyphae. A previous study showed that the SAICAR synthetase-encoding gene MoADE1 is involved in the pathogenicity of M. oryzae but did not elicit plant defense response (Fernandez et al, 2013). Thus we focused on the synthesis of arginine and found that continuous exogenous arginine could suppress the pathogenicity defects of the interestingly Δ Mocpa2 mutant on barley leaves, which was consistent with the excised leaf-sheath assay results.…”

Section: Discussionmentioning

confidence: 99%

“…Cystathionine beta-lyase (MoStr3) and methylene tetrahydrofolate reductase (MoMet13) affect growth and development processes by regulating methionine biosynthesis (Wilson et al, 2012; Yan et al, 2013). SAICAR synthetase (MoAde1) is required for de novo adenine biosynthesis and pathogenicity (Fernandez et al, 2013). Orotate phosphoribosyl transferase (MoPyr5) is involved in uridine 5′-phosphate synthesis and controls the virulence of M. oryzae (Qi et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Carbamoyl Phosphate Synthetase Subunit MoCpa2 Affects Development and Pathogenicity by Modulating Arginine Biosynthesis in Magnaporthe oryzae

et al. 2016

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Arginine is a semi-essential amino acid that affects physiological and biochemical functions. The CPA2 gene in yeast encodes a large subunit of arginine-specific carbamoyl phosphate synthetase (CPS) and is involved in arginine biosynthesis. Here, an ortholog of yeast CPA2 was identified in the rice blast fungus Magnaporthe oryzae, and was named MoCPA2. MoCpa2 is an 1180-amino acid protein which contains an ATP grasp domain and two CPSase domains. Targeted deletion of MoCPA2 supported its role in de novo arginine biosynthesis in M. oryzae as mutant phenotypes were complemented by arginine but not ornithine. The ΔMocpa2 mutant exhibited defects in asexual development and pathogenicity but not appressorium formation. Further examination revealed that the invasive hyphae of the ΔMocpa2 mutant were restricted mainly to the primary infected cells. In addition, the ΔMocpa2 mutant was unable to induce a plant defense response and had the ability to scavenge ROS during pathogen-plant interactions. Structure analysis revealed that the ATP grasp domain and each CPS domain were indispensable for the proper localization and full function of MoCpa2. In summary, our results indicate that MoCpa2 plays an important role in arginine biosynthesis, and affects growth, conidiogenesis, and pathogenicity. These results suggest that research into metabolism and processes that mediate amino acid synthesis are valuable for understanding M. oryzae pathogenesis.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Carbamoyl Phosphate Synthetase Subunit MoCpa2 Affects Development and Pathogenicity by Modulating Arginine Biosynthesis in Magnaporthe oryzae

et al. 2016

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“…Recently, we have shown how biotrophic growth is dependent on endogenous sources of purines [47] and methionine [38] despite their abundance in host cells [47], thus experimentally confirming the host environment to be nitrogen-poor during early infection, at least from the perspective of the fungus [18], [47]. We have suggested that this demand for endogenously produced nitrogenous compounds could be a trade-off between the nitrogen requirements of the fungus on the one hand, and the need to maintain the EIHM - a likely barrier to amino acid and purine uptake - on the other [14], [47]. Such a trade-off might persist if M. oryzae biotrophic hyphae, similar to those of Colletotrichum species [48], function primarily as platforms for effector accumulation and delivery [47].…”

Section: Discussionmentioning

confidence: 99%

Characterizing Roles for the Glutathione Reductase, Thioredoxin Reductase and Thioredoxin Peroxidase-Encoding Genes of Magnaporthe oryzae during Rice Blast Disease

Fernandez

Wilson

2014

PLoS ONE

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Understanding how pathogenic fungi adapt to host plant cells is of major concern to securing global food production. The hemibiotrophic rice blast fungus Magnaporthe oryzae, cause of the most serious disease of cultivated rice, colonizes leaf cells asymptomatically as a biotroph for 4–5 days in susceptible rice cultivars before entering its destructive necrotrophic phase. During the biotrophic growth stage, M. oryzae remains undetected in the plant while acquiring nutrients and growing cell-to-cell. Which fungal processes facilitate in planta growth and development are still being elucidated. Here, we used gene functional analysis to show how components of the NADPH-requiring glutathione and thioredoxin antioxidation systems of M. oryzae contribute to disease. Loss of glutathione reductase, thioredoxin reductase and thioredoxin peroxidase-encoding genes resulted in strains severely attenuated in their ability to grow in rice cells and that failed to produce spreading necrotic lesions on the leaf surface. Glutathione reductase, but not thioredoxin reductase or thioredoxin peroxidase, was shown to be required for neutralizing plant generated reactive oxygen species (ROS). The thioredoxin proteins, but not glutathione reductase, were shown to contribute to cell-wall integrity. Furthermore, glutathione and thioredoxin gene expression, under axenic growth conditions, was dependent on both the presence of glucose and the M. oryzae sugar/ NADPH sensor Tps1, thereby suggesting how glucose availability, NADPH production and antioxidation might be connected. Taken together, this work identifies components of the fungal glutathione and thioredoxin antioxidation systems as determinants of rice blast disease that act to facilitate biotrophic colonization of host cells by M. oryzae.

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“…Leaf sheaths were inoculated with fungal spores (1×10 5 spores ml −1 in 0.20% gelatin) in the hollow interior of the sheaths as described previously [37]. Infected sheaths were kept horizontal in a glass container with humid conditions for up to 48 hr.…”

Section: Methodsmentioning

confidence: 99%

Evidence for a Transketolase-Mediated Metabolic Checkpoint Governing Biotrophic Growth in Rice Cells by the Blast Fungus Magnaporthe oryzae

2014

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The blast fungus Magnaporthe oryzae threatens global food security through the widespread destruction of cultivated rice. Foliar infection requires a specialized cell called an appressorium that generates turgor to force a thin penetration hypha through the rice cuticle and into the underlying epidermal cells, where the fungus grows for the first days of infection as a symptomless biotroph. Understanding what controls biotrophic growth could open new avenues for developing sustainable blast intervention programs. Here, using molecular genetics and live-cell imaging, we dismantled M. oryzae glucose-metabolizing pathways to reveal that the transketolase enzyme, encoded by TKL1, plays an essential role in facilitating host colonization during rice blast disease. In the absence of transketolase, Δtkl1 mutant strains formed functional appressoria that penetrated rice cuticles successfully and developed invasive hyphae (IH) in rice cells from primary hyphae. However, Δtkl1 could not undertake sustained biotrophic growth or cell-to-cell movement. Transcript data and observations using fluorescently labeled histone H1:RFP fusion proteins indicated Δtkl1 mutant strains were alive in host cells but were delayed in mitosis. Mitotic delay could be reversed and IH growth restored by the addition of exogenous ATP, a metabolite depleted in Δtkl1 mutant strains. We show that ATP might act via the TOR signaling pathway, and TOR is likely a downstream target of activation for TKL1. TKL1 is also involved in controlling the migration of appressorial nuclei into primary hyphae in host cells. When taken together, our results indicate transketolase has a novel role in mediating - via ATP and TOR signaling - an in planta-specific metabolic checkpoint that controls nuclear migration from appressoria into primary hyphae, prevents mitotic delay in early IH and promotes biotrophic growth. This work thus provides new information about the metabolic strategies employed by M. oryzae to enable rice cell colonization.

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Growth in rice cells requires de novo purine biosynthesis by the blast fungus Magnaporthe oryzae

Cited by 48 publications

References 31 publications

Carbamoyl Phosphate Synthetase Subunit MoCpa2 Affects Development and Pathogenicity by Modulating Arginine Biosynthesis in Magnaporthe oryzae

Carbamoyl Phosphate Synthetase Subunit MoCpa2 Affects Development and Pathogenicity by Modulating Arginine Biosynthesis in Magnaporthe oryzae

Characterizing Roles for the Glutathione Reductase, Thioredoxin Reductase and Thioredoxin Peroxidase-Encoding Genes of Magnaporthe oryzae during Rice Blast Disease

Evidence for a Transketolase-Mediated Metabolic Checkpoint Governing Biotrophic Growth in Rice Cells by the Blast Fungus Magnaporthe oryzae

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