Fungicidal properties of ginger (Zingiber officinale) essential oils against Phytophthora colocasiae.

Recently, plant essential oils (EOs) have attracted special attention in plant disease control and food preservation. Since ancient times, essential oils extracted from plants have exhibited many biological characteristics, especially antimicrobial properties. Recent studies have described the potentials of EOs and derivatives to inhibit the growth and reproduction of microorganisms, mainly in response of overwhelming concerns of consumers about food safety. In the context of returning to nature, with the advancement of science and technology and improved living standards, people have begun to seek solutions for food hygiene without chemical additives. Therefore, biological pesticides and plant-oriented chemicals have received special attention from scientists because they are environmentally friendly and nonhazardous, sustainable, and effective alternatives against many noxious phytopathogens. Present study is intended to appraise the fungicidal properties of ginger EOs to combat leaf blight disease of taro, which threatens global taro production. Farmers often hinge on extremely toxic synthetic fungicides to manage diseases, but the residual effects and resistance of chemicals are unavoidable. The microwave-assisted hydrodistillation method was used for ginger EOs extraction and an FTIR (ATR) spectrometer was used to evaluate their chemical composition and citral was identified as most abundant compound (89.05%) in oil. The pathogen isolated from lesions of diseased taro plants was identified as Phytophthora colocasiae and used as test fungus in the present study. Ginger EO was evaluated in-vitro for antifungal properties against mycelium growth, sporangium production, zoospore germination, leaf, and corm necrosis inhibition. Repeated experiments have shown that the concentration of ginger essential oil (1250 ppm) proved to be the lowest dose to obtain 100% inhibition of fungal growth and spore germination, sporangia formation and leaf necrosis assessment. These results are derived from this fungal species and a hypothesis that involves further research on other plant pathogens to demonstrate the overall potency of essential oils. This study references the easy, economic, and environmental management and control of plant diseases using essential oils and byproducts.

C-coordinated O-carboxymethyl chitosan Cu(II) complex exerts antifungal activity by disrupting the cell membrane integrity of Phytophthora capsici Leonian.

Damage to the cell membrane is an effective method to prevent drug resistance in plant fungal diseases. Here, we proposed a negative remodeling model of the cell membrane structure induced by the C-coordinated O-carboxymethyl chitosan Cu (II) complex (O-CSLn-Cu). FITC-labeled O-CSLn-Cu (FITC-O-CSLn-Cu) was first synthesized via a nucleophilic substitution reaction and confirmed by FT-IR. FITC-labeled O-CSLn-Cu could pass through the fungal cell membrane, as detected by confocal laser scanning microscopy (CLSM) coupled with fluorescein isothiocyanate (FITC)-fluorescence. O-CSLn-Cu treatment led to apparent morphological changes in the membranes of P. capsici Leonian and giant unilamellar vesicles (GUVs) by transmission electron microscopy (TEM). Then, we performed component analysis of the cell membrane from the P. capsici Leonian affected by O-CSLn-Cu with a particular interest in membrane physicochemical properties. Many unsaturated fatty acids (UFAs) and key enzymes promoting UFA synthesis of the cell membrane were downregulated. Similarly, a large number of membrane proteins responsible for substance transport and biochemical reactions were downregulated. Furthermore, O-CSLn-Cu treatments increased plasma membrane permeability with significant leakage of intercellular electrolytes, soluble proteins and sugars, and lipid peroxidation with decreasing membrane fluidity. Finally, aquaporin 10 was proven to be a potential molecular target sensitive to antimicrobial agents according to composition analysis of membrane structure and immunohistochemistry.

Cryopreservation of Fern Spores and Pollen.

Fern spores and pollen are haploid plant germplasm of microscopic nature that can be used to regenerate full plants through germination (fern spores) or to fertilize seed-bearing plants through breeding programs (pollen). Due to their short life span in conventional storage (i.e., dry at -20 °C), the use of cryopreservation has been indicated for long-term ex situ conservation. While fern spores of most species and pollen from many seeded plants tolerate desiccation and can be stored dry at liquid nitrogen temperatures, some pollen is desiccation sensitive, and cryopreservation protocols require controlled drying and cooling and some level of cryoprotection. In this chapter we describe the cryopreservation process for fern spores used in the Millennium Seed Bank of Royal Botanic Gardens, Kew, including some details of the fern spores harvest and cleaning methods. In addition, two protocols for pollen cryopreservation are described, one generic for desiccation-tolerant pollen that can be used for multiple species and one specific for a desiccation sensitive pollen (Zea mays).

2-Phenylethyl Isothiocyanate Exerts Antifungal Activity against Alternaria alternata by Affecting Membrane Integrity and Mycotoxin Production.

Black spot caused by Alternaria alternata is one of the important diseases of pear fruit during storage. Isothiocyanates are known as being strong antifungal compounds in vitro against different fungi. The aim of this study was to assess the antifungal effects of the volatile compound 2-phenylethyl isothiocyanate (2-PEITC) against A. alternata in vitro and in pear fruit, and to explore the underlying inhibitory mechanisms. The in vitro results showed that 2-PEITC significantly inhibited spore germination and mycelial growth of A. alternata-the inhibitory effects showed a dose-dependent pattern and the minimum inhibitory concentration (MIC) was 1.22 mM. The development of black spot rot on the pear fruit inoculated with A. alternata was also significantly decreased by 2-PEITC fumigation. At 1.22 mM concentration, the lesion diameter was only 39% of that in the control fruit at 7 days after inoculation. Further results of the leakage of electrolyte, increase of intracellular OD260, and propidium iodide (PI) staining proved that 2-PEITC broke cell membrane permeability of A. alternata. Moreover, 2-PEITC treatment significantly decreased alternariol (AOH), alternariolmonomethyl ether (AME), altenuene (ALT), and tentoxin (TEN) contents of A. alternata. Taken together, these data suggest that the mechanisms underlying the antifungal effect of 2-PEITC against A. alternata might be via reduction in toxin content and breakdown of cell membrane integrity.

Effects of sophorolipids on fungal and oomycete pathogens in relation to pH solubility.

AIMS: The objective of this study was to determine the effects of sophorolipids on several fungal and oomycete plant pathogens and the relationship between sophorolipids at different pH and antimicrobial activities. METHODS AND RESULTS: Sophorolipids had different solubility at different pH with a dramatic increase in solubility when pH was 6 or higher. Inhibition of mycelial growth of Phytophthora infestans by sophorolipids was affected by pH values, showing that when the pH value was higher, the inhibition rate was lower. Sophorolipids inhibited spore germination and mycelial growth of several fungal and oomycete pathogens in vitro including Fusarium sp., F. oxysporum, F. concentricum, Pythium ultimum, Pyricularia oryzae, Rhizoctorzia solani, Alternaria kikuchiana, Gaeumannomyces graminis var. tritici and P. infestans and caused morphological changes in hyphae by microscope observation. Sophorolipids reduced ß-1,3-glucanase activity in mycelia of P. infestans. In greenhouse studies, foliar application of sophorolipids at 3 mg ml-1 reduced severity of late blight of potato caused by P. infestans significantly. CONCLUSION: Sophorolipids influenced spore germination and hyphal tip growth of several plant pathogens and pH solubility of sophorolipids had an effect on their efficacy. Application of sophorolipids reduced late blight disease on potato under greenhouse conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: The findings indicated that sophorolipids have the potential to be developed as a convenient and easy-to-use formulation for managing plant diseases.

[Vancomycin-based Lowenstein-Jensen selective medium for reducing contamination of mycobacterial cultures by spore-forming bacteria]. / Milieu sélectif de Lowenstein-Jensen à base de vancomycine pour la réduction des contaminations de cultures de mycobactéries par les bactéries sporulantes.

INTRODUCTION: despite the development of new methods, culture on solid medium is the gold standard for the diagnosis of tuberculosis. However, this method is associated with increased rates of contamination of cultures by spore-forming bacteria. These bacteria are generally sensitive to vancomycin and to a combinsation of vancomycin, colistin, nystatin, and trimethoprim (VCNT). The purpose of this study was to assess the effectiveness of VCNT-based selective Lowenstein-Jensen (LJ) medium in reducing contamination of cultures by spore-forming bacteria. METHODS: sputum samples, collected from the 120 TB and non-TB patients included in the study between October 2016 and May 2017, were decontaminated with the modified Petroff method. Decontamination pellets were inoculated onto conventional LJ media and selective VCNT-based LJ medium containing 10µg/ml vancomycin. Fifteen strains of spore-forming bacteria were inoculated onto the same media in order to assess their sensitivity to VCNT. RESULTS: the contamination of cultures on VCNT-based LJ medium containing 10µg/ml of vancomycin and LJ medium were 11.66% (14/120) and 39.16% (47/120) with p <0.0001, respectively. Sensitivity of spore-forming bacteria to VCNT decreased with the increasing of culture incubation time. CONCLUSION: VCNT-based selective LJ medium containing 10µg/ml vancomycin led to a significant reduction in the rate of culture contamination. This environment could contribute to improve the quality of mycobacterial cultures and thus bacteriological diagnosis of tuberculosis.

Antimicrobial and Phytotoxic Activity of Origanum heracleoticum and O. majorana Essential Oils Growing in Cilento (Southern Italy).

There is a growing interest in a potential use of essential oils (EOs) as a replacement for traditional pesticides and herbicides. The aims of this study were to: (i) Identify the chemical composition of the two EOs derived from Origanum heracleoticum L. and O. majorana L., (ii) evaluate the in vitro antifungal activity of the EOs against some postharvest phytopathogens (Botrytis cinerea, Penicillium expansum, Aspergillus niger and Monilinia fructicola), (iii) evaluate the in vitro antibacterial activity against Bacillus megaterium, Clavibacter michiganensis, Xanthomonas campestris, Pseudomonas fluorescens and P. syringae pv. phaseolicola, (iv) evaluate the effect of both studied EOs on the spore germination percentage and their minimum inhibitory concentration (MIC) against M. fructicola, and (v) study the possible phytotoxicity of the two EOs and their major constituents, carvacrol for O. heracleoticum and terpinen-4-ol for O. majorana, against tha germination and initial radicle growth of radish, lettuce, garden cress and tomato. The two EOs demonstrated promising in vitro antimicrobial and antifungal activities against all tested microorganisms. EOs showed high inhibition of spore germination percentage at the minimal inhibitory concentration of 500 and 2000 µg/mL, respectively. Moreover, both germination and radical elongation of selected plant species were sensitive to the oils.

Genetic and Functional Analyses of the DKxanthene Biosynthetic Gene Cluster from Myxococcus stipitatus DSM 14675.

DKxanthenes are a class of yellow secondary metabolites produced by myxobacterial genera Myxococcus and Stigmatella. We identified a putative 49.5 kb DKxanthene biosynthetic gene cluster from Myxococcus stipitatus DSM 14675 by genomic sequence and mutational analysis. The cluster was comprisedof 15 genes (MYSTI_06004-MYSTI_06018) encoding polyketide synthases, non-ribosomal peptide synthases, and proteins with unknown functions. Disruption of the genes by plasmid insertion resulted in defects in the production of yellow pigments. High-performance liquid chromatography and liquid chromatography-tandem mass spectrometry analysis indicated that the yellow pigments produced by M. stipitatus DSM 14675 might be noble DKxanthene derivatives. M. stipitatus did not require DKxanthenes for the formation of heat-resistant viable spores, unlike Myxococcus xanthus. Furthermore, DKxanthenes showed growth inhibitory activity against the fungi Aspergillus niger, Candida albicans, and Rhizopus stolonifer.

Class C ARFs evolved before the origin of land plants and antagonize differentiation and developmental transitions in Marchantia polymorpha.

A plethora of developmental and physiological processes in land plants is influenced by auxin, to a large extent via alterations in gene expression by AUXIN RESPONSE FACTORs (ARFs). The canonical auxin transcriptional response system is a land plant innovation, however, charophycean algae possess orthologues of at least some classes of ARF and AUXIN/INDOLE-3-ACETIC ACID (AUX/IAA) genes, suggesting that elements of the canonical land plant system existed in an ancestral alga. We reconstructed the phylogenetic relationships between streptophyte ARF and AUX/IAA genes and functionally characterized the solitary class C ARF, MpARF3, in Marchantia polymorpha. Phylogenetic analyses indicate that multiple ARF classes, including class C ARFs, existed in an ancestral alga. Loss- and gain-of-function MpARF3 alleles result in pleiotropic effects in the gametophyte, with MpARF3 inhibiting differentiation and developmental transitions in multiple stages of the life cycle. Although loss-of-function Mparf3 and Mpmir160 alleles respond to exogenous auxin treatments, strong miR-resistant MpARF3 alleles are auxin-insensitive, suggesting that class C ARFs act in a context-dependent fashion. We conclude that two modules independently evolved to regulate a pre-existing ARF transcriptional network. Whereas the auxin-TIR1-AUX/IAA pathway evolved to repress class A/B ARF activity, miR160 evolved to repress class C ARFs in a dynamic fashion.

Development of an efficient conjugal DNA transfer system between Escherichia coli and a non-sporulating Streptomyces strain.

Bacterial conjugation is a powerful tool used for DNA transfer from Escherichia coli into various bacteria including streptomycetes. In this methodology, spores are usually employed as recipient cells of the genetic information. However, some industrially important Streptomyces do not produce spores making difficult their genetic manipulation. In these strains, the use of mechanically fragmented mycelia allows DNA transfer with low efficiency. Streptomyces peucetius var. caesius is a non-sporulating bacteria which produces the antitumor compound doxorubicin. The use of aerial mycelia of this microorganism, failed to get intergeneric conjugation with E. coli. In the present work, by using young aerial mycelia of this microorganism and an excess of E. coli cells (~7×108cellsmL-1) in soybean-mannitol medium (MS) supplemented with 20mMMgCl2 resulted in a high number of exconjugant colonies (5×10-4) when compared to other reports from this genus (1.1×10-5 to 2.5×10-8). The effectiveness of these conditions was confirmed by isolating null mutants of two different glucokinases from S. peucetius var. caesius. The novelty in using young aerial mycelia as receptor cells, allowed an efficient conjugative process and opened the way for genetic manipulation of additional non-spore forming actinobacteria exhibiting natural resistance to be genetically manipulated.

Effects of postharvest oligochitosan treatment on fungal diseases and defence responses in Dongxue peach fruit.

In this study, the effects of oligochitosan treatment on controlling postharvest diseases in Dongxue peach ( Prunus Persica L. Batsch, cv Dongxuemi) were examined and the possible underlying mechanisms were discussed. Results showed that the disease incidence and lesion area in peach fruit inoculated with Monilinia fructicola and Penicillium expansum were all remarkably reduced by oligochitosan treatment. Oligochitosan treatment inhibited spore germination and mycelial growth of the two fungi in vitro. Oligochitosan treatment also induced upregulation of the salicylic acid signalling pathway-related genes (NPR1, PR1 and phenylalanine ammonia lyase) and enhanced the levels of total phenolics, flavonoids and lignin in peach. Meanwhile, enzymatic activities of superoxide dismutase, catalase, polyphenoloxidase, ascorbate peroxidase and phenylalanine ammonia lyase also increased. These findings suggest that the effects of oligochitosan on the disease control of peach fruit may be associated with its direct antimicrobial effects as well as increasing antioxidant, phenylpropanoid metabolism and accumulating antifungal compounds by activating the salicylic acid-dependent pathway.

Morphological and transcriptomic evidence for ammonium induction of sexual reproduction in Thalassiosira pseudonana and other centric diatoms.

The reproductive strategy of diatoms includes asexual and sexual phases, but in many species, including the model centric diatom Thalassiosira pseudonana, sexual reproduction has never been observed. Furthermore, the environmental factors that trigger sexual reproduction in diatoms are not understood. Although genome sequences of a few diatoms are available, little is known about the molecular basis for sexual reproduction. Here we show that ammonium reliably induces the key sexual morphologies, including oogonia, auxospores, and spermatogonia, in two strains of T. pseudonana, T. weissflogii, and Cyclotella cryptica. RNA sequencing revealed 1,274 genes whose expression patterns changed when T. pseudonana was induced into sexual reproduction by ammonium. Some of the induced genes are linked to meiosis or encode flagellar structures of heterokont and cryptophyte algae. The identification of ammonium as an environmental trigger suggests an unexpected link between diatom bloom dynamics and strategies for enhancing population genetic diversity.

In vitro effect of two commercial anti-coccidial drugs against myxospores of Kudoa septempunctata genotype ST3 (Myxozoa, Multivalvulida).

Kudoa septempunctata (Myxozoa: Multivalvulida) myxospores infect the trunk muscles of olive flounder (Paralichthys olivaceus). In this study, two popular commercially formulated anti-coccidial drugs (amprolium hydrochloride and toltrazuril) were serially diluted and incubated with purified mature Kudoa septempunctata myxospores. The viability of K. septempunctata spores was determined after a 2-day incubation followed by Hoechst 33342 and propidium iodide staining, and scanning electron microscopy. Amprolium hydrochloride significantly decreased spore viability (18% of control) at a concentration of 920 µg/mL, whereas toltrazuril showed almost no effect (83% of control). Viability of the control (untreated spores) was 90%. In vivo studies are required to confirm the efficacy of amprolium hydrochloride in fish infected with K. septempunctata myxospores on their growth and immune system performance.

Asexual Recombinants of Plasmopara halstedii Pathotypes from Dual Infection of Sunflower.

Genetically homogenous strains of Plasmopara halstedii differing in host specificity and fungicide tolerance were used to test the hypothesis that asexual genetic recombination occurs and may account for the high genotype diversity of this homothallic reproducing oomycete, which causes downy mildew in sunflower. Dual inoculation of sunflower seedlings with single zoospore strains of complementary infection characteristics caused sporulation under conditions where inoculation with each strain alone failed to infect. PCR-based investigation with strain-specific primers proved the presence of genetic traits from both progenitors in single sporangia collected from sporangiophores of such infections. Sister zoospores released from these sporangia revealed the genotype of the one or the other parental strain thus indicating heterokaryology of sporangia. Moreover, some zoospores showed amplification products of both parents, which suggests that the generally mononucleic spores derived from genetic recombination. The possibility of parasexual genetic exchange in the host-independent stage of infection and the evolutionary consequences are discussed.

The decision to germinate is regulated by divergent molecular networks in spores and seeds.

Dispersal is a key step in land plant life cycles, usually via formation of spores or seeds. Regulation of spore- or seed-germination allows control over the timing of transition from one generation to the next, enabling plant dispersal. A combination of environmental and genetic factors determines when seed germination occurs. Endogenous hormones mediate this decision in response to the environment. Less is known about how spore germination is controlled in earlier-evolving nonseed plants. Here, we present an in-depth analysis of the environmental and hormonal regulation of spore germination in the model bryophyte Physcomitrella patens (Aphanoregma patens). Our data suggest that the environmental signals regulating germination are conserved, but also that downstream hormone integration pathways mediating these responses in seeds were acquired after the evolution of the bryophyte lineage. Moreover, the role of abscisic acid and diterpenes (gibberellins) in germination assumed much greater importance as land plant evolution progressed. We conclude that the endogenous hormone signalling networks mediating germination in response to the environment may have evolved independently in spores and seeds. This paves the way for future research about how the mechanisms of plant dispersal on land evolved.

Oligomycins and pamamycin homologs impair motility and induce lysis of zoospores of the grapevine downy mildew pathogen, Plasmopara viticola.

Four antibiotics (pamamycin, oligomycin A, oligomycin B and echinosporin) were isolated and characterized from the fermentation broth of the marine Streptomyces strains B8496 and B8739. Bioassays revealed that each of these compounds impaired motility and caused subsequent lysis of P. viticola zoospores in a dose- and time-dependent manner. Pamamycin displayed the strongest motility inhibitory and lytic activities (IC50 0.1 µg mL(-1)) followed by oligomycin B (IC50 0.15 and 0.2 µg mL(-1)) and oligomycin F (IC50 0.3 and 0.5 µg mL(-1)). Oligomycin A and echinosporin also showed motility inhibitory activities against the zoospores with IC50 values of 3.0 and 10.0 µg mL(-1), respectively. This is the first report of motility inhibitory and lytic activities of these antibiotics against zoospores of a phytopathogenic peronosporomycete. Structures of all the isolated compounds were determined based on detailed spectroscopic analysis.

Enhancement of downy mildew disease resistance in pearl millet by the G_app7 bioactive compound produced by Ganoderma applanatum.

Pearl millet (Pennisetum glaucum) stands sixth among the most important cereal crops grown in the semi-arid and arid regions of the world. The downy mildew disease caused by Sclerospora graminicola, an oomycete pathogen, has been recognized as a major biotic constraint in pearl millet production. On the other hand, basidiomycetes are known to produce a large number of antimicrobial metabolites, providing a good source of anti-oomycete agrochemicals. Here, we report the discovery and efficacy of a compound, named G_app7, purified from Ganoderma applanatum on inhibition of growth and development of S. graminicola, as well as the effects of seed treatment with G_app7 on protection of pearl millet from downy mildew. G_app7 consistently demonstrated remarkable effects against S. graminicola by recording significant inhibition of sporangium formation (41.4%), zoospore release (77.5%) and zoospore motility (91%). Analyses of G_app7 compound using two-dimensional nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry revealed its close resemblance to metominostrobin, a derivative of strobilurin group of fungicides. Furthermore, the G_app7 was shown to stably maintain the inhibitory effects at different temperatures between 25 and 80 °C. In addition, the anti-oomycete activity of G_app7 was fairly stable for a period of at least 12 months at 4 °C and was only completely lost after being autoclaved. Seed treatment with G_app7 resulted in a significant increase in disease protection (63%) under greenhouse conditions compared with water control. The identification and isolation of this novel and functional anti-oomycete compound from G. applanatum provide a considerable agrochemical importance for plant protection against downy mildew in an environmentally safe and economical manner.

A New Lactone from Chaetomium globosum Strain M65 that Inhibits the Motility of Zoospores.

In a search for endophytes from medicinal plants of Bangladesh, we isolated the M65 fungal strain from the fruit of Azadirachta indica. Following chemical screening, chromatographic purification of the culture extract of strain M65 led to the isolation of the previously reported lasiodiplodin (2), the known derivative 1, and the new derivative 3a, along with two further known compounds (4 and 5). The new (3R,5R)-5-hydroxylasiodiplodin (3a), the enantiomer of the known (3S,5S)-5-hydroxylasiodiplodin (3b), inhibited the motility of zoospores of a devastating late blight phytopathogen Phytophthora capsici by 100% at a concentration of 10 µg/mL. The respective activities of the other metabolites were negligible.

In Vitro Inactivation of Kudoa septempunctata Spores Infecting the Muscle of Olive Flounder Paralichthys olivaceus.

Kudoa septempunctata, a myxosporean parasite infecting the trunk muscles of olive flounder (Paralichthys olivaceus), has been recently reported to be the causative agent of a type of food poisoning in humans. Patients exhibited acute diarrhea and vomiting after ingestion of the raw flesh of infected flounder. A recent increase in the number of food-poisoning cases has prompted us to develop a control strategy of this parasite. In this study, we evaluated the efficacy of several temperature and chemical treatments for inactivating K. septempunctata spores in vitro using the vital staining assay with the fluorescent dyes Hoechst 33342 and propidium iodide (PI). Screening tests of treatment methods against K. septempunctata suggested that 25% ethanol for 5 min, 80°C for 10 s, limonene at 10 µL/mL for 5 min, and salinities at 0‰ and 160‰ for 5 min were effective for killing spores. To verify toxicity loss in K. septempunctata spores after the treatments, tight junction barrier integrity assays with Caco-2 cells were conducted. The results of the Caco-2 assays corresponded well with those of the Hoechst 33342-PI staining assay. Further studies are required to determine a practical treatment procedure for inactivating spores considering the treatment application in the production process of cultured olive flounder.

Macrocyclic Trichothecenes from Myrothecium roridum Strain M10 with Motility Inhibitory and Zoosporicidal Activities against Phytophthora nicotianae.

The cytotoxicity of the extract obtained from Myrothecium roridum M10 and a characteristic (1)H signal at δH ∼8 led to the assumption that verrucarin/roridin-type compounds were present. Upscaling on rice medium led to the isolation of four new metabolites: verrucarins Y (1) and Z (6) (macrocyclic trichothecenes), bilain D (12) (a diketopiperazine derivative), and hamavellone C (14) (an unusual cyclopropyl diketone). In addition, nine known trichothecenes [verrucarin A (3), 16-hydroxyverrucarin A (5), verrucarin B (7), 16-hydroxyverrucarin B (8), verrucarin J (2), verrucarin X (4), roridin A (9), roridin L-2 (10), and trichoverritone (11)] and a bicyclic lactone [myrotheciumone A (15)] were identified. Their structures and configurations were determined by spectroscopic methods, published data, Mosher's method, and considering biosyntheses. Some trichothecenes showed motility inhibition followed by lysis of the zoospores against devastating Phytophthora nicotianae within 5 min. Compounds 2, 3, 7, and 9 also exhibited potent activities against Candida albicans and Mucor miehei.