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Plant hormones are a group of structurally diverse small compounds that orchestrate the cellular processes governing proper plant growth and environmental adaptation. To understand the details of hormonal activity, we must study not only their inherent activities but also the cross-talk among plant hormones. In addition to their use in agriculture, plant chemical activators, such as probenazole and uniconazole, have made great contributions to understand hormonal cross-talk. However, the use of plant chemical activators is limited due to the lack of activators for certain hormones. For example, to the best of our knowledge, there are only a few chemical activators previously known to stimulate the accumulation of ABA in plants, such as absinazoles and proanthocyanidins. In many cases, antagonistic effects have been examined in experiments using exogenously applied ABA, although these studies did not account for biologically relevant concentrations. In this report, it was found that a natural product, theobroxide, had potential as a plant chemical activator for stimulating the accumulation of ABA. Using theobroxide, the antagonistic effect of ABA against GAs was proved without exogenously applying ABA or using mutant plants. Our results suggest that ABA levels could be chemically controlled to elicit ABA-dependent biological phenomena.

(+)-(2S,3R)-Piscidic acid was efficiently synthesized with high optical purity (90% e.e.) via Sharpless catalytic asymmetric dihydroxylation of a trisubstituted olefin in only 6 steps from commercially available 4-hydroxyphenylpyruvic acid as the starting material. The reaction proceeded with high optical purity by using the chiral ligands, dihydroquinidine 2,5-diphenyl-4,6-pyrimidinediyl diether or dihydroquinidine 1,4-anthraquinonediyl diether.

Theobroxide has been isolated from culture filtrates of Lasiodiplodia theobromae as a potato tuber-inducing compound. In this study, the metabolism of theobroxide was investigated using cowpea as an experimental model and [2H3-7]theobroxide as a substrate for analyzing a metabolite, which revealed that theobroxide applied exogenously to the roots was converted into 3-O-β-D-glucopyranosyltheobroxide.

Heinz body hemolysis factors were isolated from boiled onion extracts and characterized as three novel sulfur-containing compounds: sodium trans-1-propenylthiosulfate, sodium cis-1-propenylthiosulfate, sodium n-propylthiosulfate.

Induction of some plant organs including tubers and flower buds begins with sensing environmental cues, such as photoperiod and temperature in the leaves. Theobroxide has been shown to induce potato tuberization and flower-bud formation in morning glory under non-inductive photoperiodic conditions, stimulating the activity of lipoxygenase (LOX) and the synthesis of jasmonic acid (JA). In the present study, the ability of theobroxide to overcome the inhibitory effect of unfavorable high temperature on the induction of tubers in potato and flower buds in morning glory was examined. Both tuber induction and flower-bud formation under non-inductive high temperatures were promoted by the application of theobroxide at a high concentration. However, although theobroxide treatment resulted in an increase in fresh weight during potato tuber growth at 30°C, morning glory plants treated with theobroxide at 35°C failed to bloom, implying that theobroxide may assist only in flower-bud formation.

In previous reports we have reported that theobroxide induces characteristic accumulation of allene oxide cyclase (AOC; EC 5.3.99.6) protein and jasmonic acid (JA) in Pharbitis nil. In the present study, PnAOC, an AOC gene from Pharbitis nil was cloned. Immunofluorescence assays indicated that the AOC protein is located in the chloroplast of vascular bundles in Pharbitis nil leaves. The PnAOC cDNA sequence lacking the chloroplast signal peptide was successfully expressed in Escherichia coli, and a gas chromatography-mass spectrum assay suggested the relative AOC activity of the recombinant PnAOC protein in comparison with Arabidopsis AOC2. Interestingly, a biphasic expression of PnAOC was induced by theobroxide, which is consistent with the accumulation patterns of AOC protein and JA. All these results indicate that AOC is the primary target of theobroxide regulation and suggest that feedback regulation of PnAOC by JA occurs upon theobroxide treatment in Pharbitis nil.

Root exudate of Vigna unguiculata was extracted from a soil system consisting of charcoal and vermiculite. Germination stimulating activity for Striga gesnerioides was found in extracts of the soil system, and an active compound was isolated. The chemical structure of the active ingredient was determined to be (+)-4-O-acetylorobanchol, based on analysis of the spectral data of 1-D and 2-D NMR together with nuclear Overhauser effect (NOE) experiments. Application of the active compound to the seeds of S. gesnerioides at a concentration of 0.35 × 10−9 mol/disk led to 69% germination. The germination observed with application of GR-24, a positive control, at 0.57 × 10−10 mol/disk was 80%.

The novel cyclic peptide, epichlicin, was isolated from Epichloe typhina, an endophytic fungus of the timothy plant (Phleum pretense L.). Its structure was determined by NMR studies and by mass spectrometry. Enantiomers of 3-amino tetradecanoic acid, a constituent amino acid of epichlicin, were synthesized as authentic standards. The stereochemistry of each amino acid was elucidated through a combination of the advanced Marfey method and chemical manipulation. Epichlicin showed inhibitory activity toward the spore germination of Cladosporium phlei, a pathogenic fungus of the timothy plant at an IC50 value of 22 nM.

In the current studies, we investigated the influences of theobroxide on stem elongation in spinach (Spinacia oleracea L.). Our results showed that stem elongation and flower formation were inhibited by spraying spinach plants with theobroxide under inductive, long day conditions (16 h light/8 h dark), while application of exogenous applied GA3 prevented the effect of theobroxide. Quantitative analysis showed that theobroxide suppressed GA1 biosynthesis, whereas the endogenous content of jasmonic acid was unchanged. However, under short day conditions (10 h light/14 h dark), there were no differences in stem length between treated and untreated plants. These results suggest that the inhibition of stem elongation by theobroxide is probably due to the suppression of gibberellin biosynthesis.

Summary Theobroxide, a novel active compound isolated from a fungus, has been reported previously to induce potato tuberization and flower bud formation in Pharbitis nil under non-inductive long-day conditions. Up to date, the action mechanism of theobroxide on flower-bud induction of P. nil, however, is still unknown. In the present study, we observed a reduction of the stem length, along with the induction of flower buds, in theobroxide-treated and short-day-grown P. nil plants. Also, the results showed that flower bud formation was delayed markedly in P. nil seedlings with removal of cotyledons or exposure to night break. The suppression effect of night-break and cotyledon-removal, however, was abolished completely by spraying theobroxide. Endogenous gibberellin1/3 contents in P. nil plants treated with theobroxide or grown under short-day conditions were relatively lower, suggesting that gibberellins probably are negatively involved in theobroxide- and short-day-induced flower-bud formation of P. nil.

Bioassay-guided investigation of the bark of Elaeocarpus parvifolius led to the isolation of three new ellagic acid derivatives, 4-O-methylellagic acid 3'-alpha-rhamnoside (2), 4-O-methylellagic acid 3'-(3''-O-acetyl)-alpha-rhamnoside (3), and 4-O-methylellagic acid 3'-(4''-O-acetyl)-alpha-rhamnoside (4) in addition to the known ellagic acid derivative, 4-O-methylellagic acid 3'-(2'',3''-di-O-acetyl)-alpha-rhamnoside (1). Their structures were elucidated on the basis of analysis of 1H NMR, 13C NMR, HMQC, HMBC and MS spectroscopic data. Compounds 1-4 were evaluated for their growth-inhibitory effect on Babesia gibsoni in vitro. Compounds 2 and 4 showed very weak activity, while compounds 1 and 3 showed moderate activity, with IC50 values of 28.5 and 52.1 microg/ml, respectively.

Theobroxide, a natural product, strongly stimulates the biosynthesis of jasmonic acid (JA) in Pharbitis nil. In this study, we investigated the accumulation of protein by the immunoblot analysis of lipoxygenase (LOX), allene oxide synthase (AOS) and allene oxide cyclase (AOC), key enzymes in JA biosynthesis, and how the endogenous levels of JA in Pharbitis nil are affected by theobroxide. The effect of JA on the accumulations of these proteins was monitored simultaneously. The results show that theobroxide treatment led to a high level accumulation of JA, which is due to high accumulations of LOX, AOS and AOC proteins induced by theobroxide treatment both under short day (SD) and long day (LD) conditions. However, under SD conditions AOS and AOC proteins are not enhanced by JA treatment. Kinetic analysis of protein levels show that a biphasic activation of AOC protein by theobroxide is displayed and the first activation of AOC protein together with elevated JA levels are observed within 30 minutes after treatment. Meanwhile, AOS and LOX proteins are activated by theobroxide later than AOC protein, suggesting that AOC plays an essential role in the initial JA formation induced by theobroxide. Since theobroxide-increased JA levels also show a biphasic manner similar to AOC activation and AOS, LOX proteins are activated later than AOC, and thus we propose a positive JA feedback regulation. Interestingly, AOS protein, which is also the enzyme for the biosynthesis of 9,10-ketol-octadecadienoic acid (KODA, a flowering inducing factor), accumulates markedly due to the simultaneous involvement of theobroxide and SD conditions, suggesting that AOS probably plays a role in flower bud formation in Pharbitis nil.

In this study, exogenous factors affecting the elongation growth in the short day plant, Pharbitis nil, was investigated. Theobroxide inhibited stem elongation in Pharbitis nil both under short day (SD) and long day (LD) conditions. Salicylhydroxamic acid (SHAM), an inhibitor of jasmonic acid (JA) biosynthesis, and GA3 recovered the inhibitory effect of theobroxide on stem elongation. Quantitative analysis of JA showed that the level of endogenous JA increased significantly in theobroxide treated plants, while exogenously applied GA3 and SHAM suppressed JA biosynthesis stimulated by theobroxide. The activity of lipoxygenase (LOX, the key enzyme of JA biosynthesis) also was stimulated by theobroxide and this stimulation was nullified by SHAM and GA3. Quantitative analysis of GA1 showed that theobroxide suppressed GA1 biosynthesis. In non theobroxide treated Pharbitis nil, SD conditions stimulated JA biosynthesis and LOX activity, while GA1 biosynthesis was suppressed. All these results suggest that JA probably is involved negatively in the control of stem elongation, and the balance between JA and gibberellin might determine the stem growth in Pharbitis nil.

Theobroxide, a novel compound isolated from fungus Lasiodiplodia theobromae culture, stimulates potato (Solanum tuberosum L.) tuber formation in vitro and in vivo, and induces flowering of Japanese morning glory (Pharbitis nil) under non-inductive long day conditions. To assess the mode of action of theobroxide in the tuberization process we measured endogenous levels of jasmonic acid and lipoxygenase activity in the cultures after the treatment with theobroxide. The results showed that theobroxide not only stimulated microtuber formation alone, but also enhanced the inductive effect of jasmonic acid when they were used in combination. The endogenous JA content increased in response to theobroxide in both old and new tissues. Moreover, theobroxide increased lipoxygenase activity in the cultures, at 2 and 3 week after culture initiation. Additionally, histological observations indicated that theobroxide might play a role in the swelling of micro-tubers formed in vitro in a similar manner as that of jasmonic acid. These results suggest that the inductive effect of theobroxide on potato micro-tuber formation might be achieved through triggering jasmonic acid production.

Life cycles of plants including tuberization and flowering are strongly related to environmental factors such as photoperiod and temperature. Theobroxide induces potato tuber formation and flower bud formation of morning glory under non-inductive conditions and stimulates the activity of lipoxygenase (LOX). In this study, to understand the LOX activity more systematically, the relationships between LOX activity and light and temperature, which effects potato tuber and flower-bud formation, have been investigated. The results showed that LOX activity in morning glory was greatly enhanced up to 30 min and then declined after switching from the light to the dark condition, while the activity did not vary when switching from the dark to the light condition. In addition, the temperature profile of measured LOX activity in the potato and morning glory plants was nearly consistent with the time taken to form potato tubers and flower buds in morning glory, respectively, at different growing temperatures. These results strongly suggest that LOX activity is directly connected with light and temperature to regulate the formation of tubers and flower-buds.

Lasiodiplodia theobromae is known as a multi-infectious microorganism that causes considerable crop damage, particularly to tropical fruits. When the fruits are infected by L. theobromae, the typical symptom is the appearance of black spots on the surface of the infected fruit. When injected in to the peel of banana, the culture filtrate of L. theobromae induced formation of black spots. The structure of the isolated compound responsible for this effect was determined to be (3S,4R)-3-carboxy-2-methylene-heptan-4-olide on the basis of analysis of MS, IR, and 1H and 13C NMR spectroscopic data, including HMQC, HMBC, and 1H-1H COSY experiments. The active compound was not only isolated from the culture filtrate derived from potato dextrose medium, but also from the extract of infected peels of bananas.

Floret opening of excised spikelets in Sorghum bicolor (L.) Moench and Sorghum Sudanesis (Piper) Stapf was significantly stimulated by immersing into 2 mM methyl jasmonate (MeJA) solution. In male sterile (MS) lines of Sorghum bicolor (L.) Moench, floret opening was more sensitive to MeJA than that in maintainer (MT) lines. Salicylic acid (SA) could abolish the effect of MeJA on the opening of spikelets. These data indicate that MeJA plays a role in floret opening in sorghum, and that SA interacts with MeJA in regulating of this process.

A new antifungal compound, (3S)-4,6-dihydro-8-methoxy-3,5-dimethyl-6-oxo-3H-2-benzopyran (4), was isolated from Penicillium expansum. During the isolation procedure 4 was determined to be unstable and readily reacted with methanol, ethanol, and water, forming three new isochromans, (1S,3S)-6-hydroxy-1,8-dimethoxy-3,5-dimethylisochroman (1), 1-ethoxy-6-hydroxy-8-methoxy-3,5-dimethylisochroman (2), and 1,6-dihydroxy-8-methoxy-3,5-dimethylisochroman (3), respectively. (3S)-6-Hydroxy-8-methoxy-3,5-dimethylisochroman (5) was reisolated from P. expansum. In fungicide disk assays, compounds 1, 2, and 4 inhibited the mycelial growth of Lasiodiplodia theobromae at 100 microg/mL by 76%, 74%, and 69%, respectively.

The inhibitory effects of 45 plant extracts selected from Central Kalimantan, Indonesia on Babesia gibsoni in vitro and their acute toxicity to mice were evaluated. Of these plant extracts studied, Arcangelisia flava, Curcuma zedoaria, Garcinia benthamiana, Lansium domesticum and Peronema canescens were found to have appreciable antibabesial activity with IC50 values from 5.3 to 49.3 microg/ml without acute toxicity in mice at the intraperitoneal dose of 0.7 g/kg of body weight.

Theobroxide is a natural compound from the fungus Lasiodiplodia theobromae and has a significantly inductive effect on potato tuber formation in vitro and in vivo. Considering the similar roles of theobroxide and jasmonic acid (JA) in tuberization, we investigated the influence of theobroxide on endogenous levels of JA and its analogue tuberonic acid (TA), as well as on lipoxygenase (LOX) activity in potato leaves. Salicylhydroxamic acid (SHAM), the JA biosynthesis inhibitor, was used to test its effect on theobroxide-induced tuber formation, on endogenous JA and TA levels, and on LOX activity. The results showed that theobroxide increased endogenous levels of JA and TA, and LOX activity. However, this inductive effect was inhibited by SHAM, associated with a reduction in tuber formation. These results suggest that the inductive effect of theobroxide on tuber formation is probably achieved by stimulating JA and TA synthesis.

The syntheses of β-resorcylic acid derivatives 1 and 2, isolated from fungus Lasiodiplodia theobromae, and their dimethyl ethers were accomplished. (R)-(−)-1,3-Butanediol was used as a chiral source of the side chain C6-synthon. The dianion of the benzoic acid moiety was alkylated with C6-bromide to give the desired skeleton. Several β-resorcylic acid derivatives including 1 and 2 were synthesized via hydrogenation, lactonization, demethylation and esterification. The (R)-configuration of the stereogenic center in the side chain was proved by this synthesis. It is confirmed that two phenolic hydroxy groups are required for 1 and 2 to exhibit potato micro-tuber inducing activity.

2001 Three new sesquiterpenoids, lubiminoic acid, epilubiminoic acid and aethione, and six known sesquiterpenoids, solavetivone, 3β-hydroxysolavetivone, 13-hydroxysolavetivone, an-hydro-β-rotunol, epilubimin and lubimin, were isolated from roots of S. aethiopicum L. Their structures were elucidated by spectroscopic data.

15-Norlubiminol and 15-norepilubiminol were obtained from Solanum aethiopicum as an inseparable 1:1 mixture in a relatively poor yield to that of the major phytoalexins, lubimin and epilubimin. Their structures were confirmed by chemical conversion starting from lubimin and epilubimin. Baeyer-Villiger oxidation of the protected lubimins with m-chloroperoxybenzoic acid provided the desired formates. Deoxygenation with triphenylphosphine selenide and subsequent methanolysis provided 15-norlubiminols, whose 1H-NMR spectra were respectively identical with that of the corresponding isomer in the natural 15-norlubiminol mixture. The antifungal activity of 15-norlubiminols would be weaker than that of lubimins.

Theobroxide is an epoxy cyclohexene compound isolated from the culture filtrate of the fungus Lasiodiplodia theobromae that induces potato microtuber formation in vitro (Nakamori and others 1994). When sprayed on potato (Solanum tuberosum L.) and morning glory (Pharbitis nil) plants, which require short days to induce tubers and flower buds, respectively, potato plants kept in noninducing conditions (long days) produced tubers. Theobroxide spray treatment also produced flower buds in morning glory plants kept under noninducing conditions (long days). Furthermore, under inducing conditions (short days), the number of flowers of seedlings sprayed with theobroxide was about 1.5 times that of controls.

Two novel resorcinol derivatives were isolated from the mycelium of Lasiodiplodia theobromae IFO 31059 as potato micro-tuber inducing compounds. Their structures were established by spectroscopic methods as ethyl (6′R)-2,4-dihydroxy-6-(6′-hydroxyheptyl)benzoate (8) and isobutyl (6′R)-2.4-dihydroxy-6-(6′-hydroxyheptyl)benzoate (9). The absolute stereochemistry of the asymmetric center of (8) was determined by an advanced Mosher method.

Qualitative and quantitative analyses of endogenous jasmonoids were done by liquid chromatography/ selected ion monitoring (LC-SIM) using deuterium-labeled compounds as internal standards. To prove the practicality of this way of analyzing the contents of endogenous jasmonoids in plants, the method was used for estimating jasmonoids in potato plants.

Cladosporium phlei as well as Epichloe typhina are natural fungal pathogens of timothy grass (Phleum pratense). An increase of resistance of the grass against C. phlei in the presence of E. typhina was already shown in several experimental designs. However, E. typhina can grow endophytically for long periods without causing external symptoms which makes the detection of infected plants and, thus, an exact evaluation of the resistance effect in the field difficult. New or modified methods were developed and used for the effective detection of the endophyte in field samples and for the isolation of both fungi. The relevance of a protective effect of E. typhina in timothy grass against infection with C. phlei was clearly established in field samples as well as in growth chamber and in vitro experiments.

The structure of cepaciamide A was revised to be (3 R ,3′ S ,2″ S ,11″ S ,12″ R )-3-[3′-(2″-hydroxy-11″,12″-methyleneoctadecanoyloxy)hexadecamido]-2-piperidinone with respect to the absolute configuration of the C 3′- and C 2″- positions and the position of the cyclopropane ring by using synthetic methods. The structure of cepaciamide B was also determined to be (3 R ,3′ S ,2″ S ,11″ Z )-3-[3′-(2″-hydroxy-11″-octadecenoyloxy)hexadecamido]-2-piperidinone.

All four stereoisomers of (2S, 3R)-(+)-piscidic acid were synthesized with high optical purity via Sharpless catalytic asymmetric dihydroxylation of (Z)- and (E)-trisubstituted olefins in 6 steps from (4-hydroxyphenyl)pyruvic acid. The Wittig reaction of methyl (4-hydroxyphenyl)pyruvate with (carbomethoxymethylene)triphenylphosphorane gave (Z)- and (E)-trisubstituted olefins in a 3:1 ratio. After protecting the phenolic hydroxyl group as the tert-butyldimethylsilyl ether, the (Z)-olefin was subjected to asymmetric dihydroxylation by using the chiral ligand, dihydroquinidine 1,4-anthraquinonediyl diether, and the reaction proceeded with 89% e.e. Desilylation and subsequent alkaline hydrolysis gave (2S, 3R)-(+)-piscidic acid. The optical purity was increased to >99% e.e. by recrystallization. The use of dihydroquinine 1,4-anthraquinonediyl diether enable (2R, 3S)-(-)-piscidic acid to be obtained. In the asymmetric dihydroxylation of the (E)-olefin, phthalazine ligands (dihydroquinidine and dihydroquinine 1,...

Three new fungal metabolites were isolated from the culture filtrate of the fungus, Lasiodiplodia theobromae IFO 31059 and identified as (5 R ) and (5 S ) 5-hydroxylasiodiplodins and 5-oxolasiodiplodin. The first two showed weak potato micro-tuber inducing activities, although only at very high dosage levels.

The Al accumulation mechanisms in an Al accumulator plant, Melastoma malabathricum L. (Melastoma), was investigated. Al was located in the upper epidermal cells and also distributed in mesophyll cells in leaf sections. In root sections, Al was found in all the root tissues, particularly in the epidermis and endodermis. Al concentrations in young leaves, mature leaves, old leaves, and roots were 8.0, 9.2, 14.4, and 10.1 mg g1, respectively. Approximately 45% of total Al in oldest leaves, and approximately 60% of total Al in leaves of other positions and roots were extracted in Tris-HCl buffer (pH 7.0). Since Al in the residual parts was mostly dissolved in hot 0.5 M H2SO4 containing 2% cetyl trimethylammonium bromide, residual Al seemed to consist mainly of monomeric Al and Al bound to pectic substances and hemicellulose. Al in the Tris-HCl extract consisted of non-monomeric Al (complexed form). Oxalate concentration in the Tris-HCl extract in leaves was significantly higher in the +Al treatment than in the –Al treatment and there was a positive correlation between the Al concentration and oxalate concentration. 27Al NMR spectrum of fresh leaves indicated the presence in the order of monomeric Al, Al-oxalate, Al-(oxalate)2, and Al-(oxalate)3 in intact leaves.

A novel potato micro-tuber-inducing compound was isolated from the culture broth of Lasiodiplodia theobromae Shimokita 2. The structure of the isolated compound was determined as (3R,6S)-6-hydroxylasiodiplodin by means of spectroscopic analyses, the modified Mosher method, and chemical conversion. The compound showed potato micro-tuber-inducing activity at a concentration of 10(-4) M, using the culture of single-node segments of potato stems in vitro.

Bioassay-guided fractionation of boiled aqueous extracts from the whole plant of Phyllanthus niruri led to the isolation of 1-O-galloyl-6-O-luteoyl-alpha-d-glucose (1), with IC(50) values of 4.7 microg/mL against Babesia gibsoni and 1.4 microg/mL against Plasmodium falciparum in vitro. The known compounds beta-glucogallin (2), quercetin 3-O-beta-d-glucopyranosyl-(2-->1)-O-beta-d-xylopyranoside (3), beta-sitosterol, and gallic acid were also isolated. Structures of these compounds were elucidated on the basis of their chemical and spectroscopic data.

the treated leaves up to 25 days after the application of [2"C](±)JA. In the other parts of the plants, the upper leaves contained the most total radioactivity, followed by the stems and lower leaves. Under long days no tubers were produced, and the radioactivity of the stolons was observed. In contrast, under short days tuber were produced, and the radioactivities were present in stolons and tubers. Flower buds and flowers were produced more under long days and accumulated high radioactivity. It is concluded from the combined data that JA is metabolized to TAG and transported to all parts of the plant. A high accumulation of TAG in tubers and flower buds may induce the formation of tubers and flower buds.

A novel fungitoxic compound, cepaciamide A, was isolated from Pseudomonas cepacia D-202. Its structure and stereochemistry were elucidated by the spectroscopic and synthetic methods.

A maize plant (Zea mays) planted in a test tube was found to inhibit the growth of the soil-borne plant pathogen, Fusarium oxysporum f. sp. melongenae. The antifungal compounds, 6-methoxybenzoxazolinone and 6,7-dimethoxybenzoxazolinone, were isolated from an ethanol extract of Zea mays roots, and (6R)-7,8-dihydro-3-oxo-alpha-ionone and (6R,9R)-7,8-dihydro-3-oxo-alpha-ionol were isolated from the root exudate.

The Solanum abutiloides plant is highly resistant to soil-borne pathogens such as Fusarium oxysporum f. sp. melongenae, Verticillium dahliae, and Ralstonia solanacearum. This species is utilized as a mating source of resistant cultivars and is also used as a rootstock. The root exudate of Solanum abutiloides was extracted from a soil system composed of charcoal and vermiculite. Anti-fungal activity was found in the extract, and an active ingredient was isolated. The chemical structure of the active compound was determined to be 3-beta-acetoxysolavetivone, a new sesquiterpenoid. The anti-fungal activity of 3-beta-acetoxysolavetivone examined by the inhibition of spore germination of Fusarium oxysporum was close to that of lubimin, and higher than that of solavetivone.

Theobroxide has been isolated from culture filtrates of Lasiodiplodia theobromae as a potato tuber-inducing compound. In this study, the metabolism of theobroxide was investigated using cowpea as an experimental model and [2H3-7]theobroxide as a substrate for analyzing a metabolite, which revealed that theobroxide applied exogenously to the roots was converted into 3- O-β-D-glucopyranosyltheobroxide.

Summary Coronatine was investigated in order to find its primary target in the biosynthesis of ethylene in cell suspension cultures of Lycopersicon peruvianum (L. p.) and Lycopersicon esculentum (L. e.). A stimulation of the ethylene forming enzyme (EFE) beginning after 30 to 60 minutes of the experiments and a decrease of the endogenous ACC-pool beginning after about 2 hours were detected, but could not be shown to be the primary effect of the toxin. Methyl jasmonate (Ja-Me) was tested in the same kind of experiments because of structural similarities with coronatine and gave effects similar to the toxin in contrast to auxin. Methyl (+)-epijasmonate was separated from its three other stereoisomers to confirm the structure activity relationship according to coronatine. Typical biotests for the toxin (hypertrophy of potato tuber tisue) as well as for the plant growth regulator (tuber induction at potato stolons) showed similar effects of coronatine and jasmonates in every case. Some structurally related compounds were tested in the cell culture system and implications for the mode of action are discused.

Fungitoxic compounds from the roots of tomato stocks, Taibyo Shinko No.1, were determined as four unsaturated hydroxy fatty acids [(13S)-13-hydroxy-(9Z, 11E)-9, 11-octadecadienoic acid, 13-hydroxy-(9E, 11E)-9, 11-octadecadienoic acid, (9S)-9-hydroxy-(10E, 12Z)-10, 12-octadecadienoic acid and 9-hydroxy-(10E, 12E)-10, 12-octadecadienoic acid], a dicarboxylic acid (azelaic acid), a quinone (2, 6-dimethoxy-p-benzoquinone) and five phenolic compounds (vanillin, syringaldehyde, p-hydroxybenzaldehyde, p-hydroxybenzoic acid, vanillic acid). It can be considered that the fungitoxic compounds related to resistance of the tomato stock against soil-borne disease were alkaloids, but not these universal compounds in plants.