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Xylanase (EIX) from the fungus Trichoderma viride elicits ethylene biosynthesis in leaf tissues of Nicotiana tabacum cv Xanthi but not in cv Hicks. The increase in ethylene biosynthesis is accompanied by an accumulation of 1-aminocyclopropane-1-carboxylic acid (ACC), an increase in extractable ACC synthase activity, and increases in ACC synthase and ACC(More)
Endophytic isolates of Trichoderma species are being considered as biocontrol agents for diseases of Theobroma cacao (cacao). Gene expression was studied during the interaction between cacao seedlings and four endophytic Trichoderma isolates, T. ovalisporum-DIS 70a, T. hamatum-DIS 219b, T. harzianum-DIS 219f, and Trichoderma sp.-DIS 172ai. Isolates DIS 70a,(More)
Pathogenic diseases represent a major constraint to the growth and yield of cacao (Theobroma cacao L.). Ongoing research on model plant systems has revealed that defense responses are activated via signaling pathways mediated by endogenous signaling molecules such as salicylic acid, jasmonic acid and ethylene. Activation of plant defenses is associated with(More)
Theobroma cacao (cacao) is cultivated in tropical climates and is exposed to drought stress. The impact of the endophytic fungus Trichoderma hamatum isolate DIS 219b on cacao's response to drought was studied. Colonization by DIS 219b delayed drought-induced changes in stomatal conductance, net photosynthesis, and green fluorescence emissions. The altered(More)
Four biologically active cDNA clones were derived from the Alternanthera mosaic virus (AltMV; genus Potexvirus) isolate, AltMV-SP, which differ in symptoms in infected Nicotiana benthamiana plants. Two clones induced necrosis and plant death; a mixture of all four clones induced milder symptoms than AltMV-SP. Replication of all clones was enhanced by a(More)
We have previously demonstrated that a protein purified from xylan-induced culture filtrates of Trichoderma viride contains beta-1,4-endoxylanase activity and induces ethylene biosynthesis in tobacco (Nicotiana tabacum cv Xanthi) leaf discs. When the ethylene biosynthesis-inducing xylanase (EIX) was applied to cut petioles of detached tobacco leaves, it(More)
Nep1 is an extracellular fungal protein that causes necrosis when applied to many dicotyledonous plants, including invasive weed species. Using transmission electron microscopy, it was determined that application of Nep1 (1.0 micro g mL(-)(1), 0.1% [v/v] Silwet-L77) to Arabidopsis and two invasive weed species, spotted knapweed (Centaurea maculosa) and(More)
Phvytophthora megakarya is a devastating oomycete pathogen that causes black pod disease in cacao. Phytophthora species produce a protein that has a similar sequence to the necrosis and ethylene inducing protein (Nep1) of Fusarium oxysporum. Multiple copies of NEP1 orthologs (PmegNEP) have been identified in P. megakarya and four other Phytophthora species(More)
ABSTRACT An epidemic of vascular wilt caused by Fusarium oxysporum f. sp. erythroxyli is currently occurring on Erythroxylum coca var. coca in the coca-growing regions of the Huallaga Valley in Peru. Random amplified polymorphic DNA (RAPD) analysis of isolates of the pathogen was undertaken to elucidate its genetic complexity, as well as to identify a(More)
Treatment of Arabidopsis (Arabidopsis thaliana) with a necrosis- and ethylene-inducing peptide (Nep1) from Fusarium oxysporum inhibited both root and cotyledon growth and triggered cell death, thereby generating necrotic spots. Nep1-like proteins are produced by divergent microbes, many of which are plant pathogens. Nep1 in the plant was localized to the(More)