Homoserine and asparagine are host signals that trigger in planta expression of a pathogenesis gene in<i>Nectria haematococca</i>

Yang, Zhennai; Rogers, Linda; Song, Yuanda; Guo, Wenjin; Kolattukudy, P.E.

doi:10.1073/pnas.0500312102

Cited by 52 publications

(38 citation statements)

References 41 publications

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“…cDNA prepared from cultured mycelium was diluted 1/100 to compensate for the biomass differences in planta. (59) showed that the pelD gene of Nectria haematococca was expressed in response to homoserine and asparagine, that a specific plant factor responsible for expression of one of these genes was identified. The inability of E. festucae Fl1 to induce lpsB expression in the presence of a plant extract suggests that the inducing factor was not stable or, alternatively, that specific signaling between the epichloë endophyte and the grass host occurs.…”

Section: Discussionmentioning

confidence: 99%

A Complex Ergovaline Gene Cluster in Epichloë Endophytes of Grasses

Fleetwood

Scott

Lane

et al. 2007

Appl Environ Microbiol

128

127

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Clavicipitaceous fungal endophytes of the genera Epichloë and Neotyphodium form symbioses with grasses of the subfamily Pooideae, in which they can synthesize an array of bioprotective alkaloids. Some strains produce the ergopeptine alkaloid ergovaline, which is implicated in livestock toxicoses caused by ingestion of endophyteinfected grasses. Cloning and analysis of a nonribosomal peptide synthetase (NRPS) gene from Neotyphodium lolii revealed a putative gene cluster for ergovaline biosynthesis containing a single-module NRPS gene, lpsB, and other genes orthologous to genes in the ergopeptine gene cluster of Claviceps purpurea and the clavine cluster of Aspergillus fumigatus. Despite conservation of gene sequence, gene order is substantially different between the N. lolii, C. purpurea, and A. fumigatus ergot alkaloid gene clusters. Southern analysis indicated that the N. lolii cluster was linked with previously identified ergovaline biosynthetic genes dmaW and lpsA. The ergovaline genes are closely associated with transposon relics, including retrotransposons and autonomous and nonautonomous DNA transposons. All genes in the cluster were highly expressed in planta, but expression was very low or undetectable in mycelia from axenic culture. This work provides a genetic foundation for elucidating biochemical steps in the ergovaline pathway, the ecological role of individual ergot alkaloid compounds, and the regulation of their synthesis in planta.

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Section: Discussionmentioning

confidence: 99%

A Complex Ergovaline Gene Cluster in Epichloë Endophytes of Grasses

Fleetwood

Scott

Lane

et al. 2007

Appl Environ Microbiol

128

127

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“…Furthermore, there is evidence that pathogens specialise to use homoserine as a host signal to trigger the expression of pathogenesis genes (Yang et al, 2005). Also, derivatives of homoserine such as homoserine lactone serve as signal substances involved in microbiological quorum sensing, enabling bacteria to communicate and coordinate behaviour and responses to nutritional status via signalling molecules (Bauer and Mathesius, 2004).…”

Section: Discussionmentioning

confidence: 99%

“…These authors used a 31 P-NMR technique that made it possible to discriminate between OPHS in the cytosol and in the chloroplasts based on a shift in the OPHS resonance spectrum caused by different pH-values. Homoserine (or its derivatives) may also function in planta as a host signal for the expression of pathogenesis genes such as pelD in Nectria haematococca (Yang et al, 2005). To gain knowledge of the role of HSK and its possible effect on OPHS levels, especially in the context of cellular compartment, we applied a transgenic approach in potato.…”

Section: Introductionmentioning

confidence: 99%

Regulation of aspartate-derived amino acid homeostasis in potato plants (Solanum tuberosum L.) by expression of E. coli homoserine kinase

et al. 2007

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Summary. The availability of the carbon backbone O-phosphohomoserine (OPHS) is critical to methionine (met) and threonine (thr) synthesis. OPHS derives from homoserine and is formed by homoserine kinase (HSK). To clarify the function of HSK in cellular metabolism, the E. coli HSK ortholog thrB was expressed in potato plants targeting the EcHSK protein to chloroplasts and to the cytosol. Both approaches resulted in up to 11 times increased total HSK enzyme activity. Transgenic plants exhibited reduced homoserine levels while met and thr did not accumulate significantly. However, the precursor cysteine and upstream intermediates of met such as cystathionine and homocysteine did indicating an accelerated carbon flow towards the end products. Coincidently, plants with elevated cytosolic levels of EcHSK exhibited a reduction in transcript levels of the endogenous HSK, as well as of threonine synthase (TS), cystathionine b-lyase (CbL), and met synthase (MS). In all plants, cystathionine g-synthase (CgS) expression remained relatively unchanged from wild type levels, while S-adenosylmethionine synthetase (SAMS) expression increased. Feeding studies with externally supplied homoserine fostered the synthesis of met and thr but the regulation of synthesis of both amino acids retained the wild type regulation pattern. The results indicate that excess of plastidial localised HSK activity does not influence the de novo synthesis of met and thr. However, expression of HSK in the cytosol resulted in the down-regulation of gene expression of pathway genes probably mediated via OPHS. We integrated these data in a novel working model describing the regulatory mechanism of met and thr homeostasis.

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“…Some examples of the latter are cell wall components that induce expression of cell wall degrading enzymes (Huertas-Gonzalez et al, 1999;RuizRoldan et al, 1999;Sexton et al, 2000), phytoalexins that induce the enzymes that can detoxify them (e.g. pisatin demethylase 1) (Straney and VanEtten, 1994), and the amino acids homoserine and asparagine, found in high levels in pea seedling hypocotyls and capable of inducing expression of pelD (Yang et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Expression of effector gene SIX1 of Fusarium oxysporum requires living plant cells

Does

Duyvesteijn

Goltstein

et al. 2008

Fungal Genetics and Biology

100

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General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. b s t r a c tFusarium oxysporum is an asexual, soil inhabiting fungus that comprises many different formae speciales, each pathogenic towards a different host plant. In absence of a suitable host all F. oxysporum isolates appear to have a very similar lifestyle, feeding on plant debris and colonizing the rhizosphere of living plants. Upon infection F. oxysporum switches from a saprophytic to an infectious lifestyle, which probably includes the reprogramming of gene expression. In this work we show that the expression of the known effector gene SIX1 of F. oxysporum f. sp. lycopersici is strongly upregulated during colonization of the host plant. Using GFP (green fluorescent protein) as reporter, we show that induction of SIX1 expression starts immediately upon penetration of the root cortex. Induction requires living plant cells, but is not host specific and does not depend on morphological features of roots, since plant cells in culture can also induce SIX1 expression. Taken together, F. oxysporum seems to be able to distinguish between living and dead plant material, preventing unnecessary switches from a saprophytic to an infectious lifestyle.

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Homoserine and asparagine are host signals that trigger in planta expression of a pathogenesis gene inNectria haematococca

Cited by 52 publications

References 41 publications

A Complex Ergovaline Gene Cluster in Epichloë Endophytes of Grasses

A Complex Ergovaline Gene Cluster in Epichloë Endophytes of Grasses

Regulation of aspartate-derived amino acid homeostasis in potato plants (Solanum tuberosum L.) by expression of E. coli homoserine kinase

Expression of effector gene SIX1 of Fusarium oxysporum requires living plant cells

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