AB5046A and B, novel chlorosis-inducing substances from Nodulisporium sp.

Abstract

Novel chlorosis-inducing substances, AB5046Aand B, were isolated from the culture broth of a fungal strain. The producing organism, designated AB5046, was identified as a member of Nodulispor ium.AB5046Aand B were purified by extraction with EtOAc and silica gel chromatography. The structure of AB5046Aand B were determined to be 2-butyryl-3,5-dihydroxy-cyclohex-2-ene-l-one and 2-acetyl-3,5-dihydroxy-cyclohex-2-enel-one, respectively, by spectroscopic analyses. AB5046Aand B induced chlorosis against Japanese barnyard millet in vitro. The chlorosis activity of these compoundswas stronger against monocotyledonsthan dicotyledons. Inhibitionsof chloroplast formation, photosynthesis and essential amino acid's biosynthesis are considered as the important and attractive targets in the development of new herbicides with low toxicity to mammals. Some herbicides such as pyrazolate1}, methoxy-phenone2), fluridone3) are practically used as the inhibitors of chloroplast formation (chlorosis-inducing chemicals). Although it is known that some natural products (virdomic acids4), alternaric acid5), rhizobitoxin6), l -amino-2-nitrocyclopentanecarboxylic acid7), tentoxin8), etc.) have chlorosis-inducing activity, they are not utilized for control of weeds. In the course of screening for new herbicides, we found that a soil fungus produced new herbicidal substances, named AB5046A(1) and B (2), which induced chlorosis against Japanese barnyard millet in vitro. The color of generating foliage of the barnyard millet became completely white, as if they were bleached, whenthe seeds were treated with these compounds.In this paper, we describe the identification of the producing organism together with the isolation, fermentation, structure determination and biological activities of 1 and 2. Materials and Methods TaxonomyThe AB5046Aand B producing organism, strain AB5046, was isolated from a soil sample collected at Seta-gun in Gummaprefecture. Morphological observations of the strain grownon malt extract agar were carried out with a light microscope (Olympus Model BHS) and a scanning electron microscope (Hitachi S-430). The characteristics of the culture on potato -dextrose agar and malt extract agar were determined after 2 weeks of incubation

A polyphasic taxonomy of Daldinia (Xylariaceae)1

“…The latter examples also show that studies on the secondary metabolites of fungi from hitherto underexplored habitats may even contribute to our knowledge on the ecology of the respective organisms. Likewise, the similarity of the chemical structures of compounds reported by Igarashi et al (1993), Kozlovsky et al . (2003) and Dai et al (2006, 2009) from endophytic species of Nodulisporium to those found from teleomorphic Xylariaceae in the course of our own work suggest that the producer organisms probably constitute anamorphic states of Daldinia or its allies.…”

A Pair of Novel Heptentriol Stereoisomers from the Ascomycete Daldinia concentrica

“…Compound 4 has also previously been isolated from the culture broth of the fungus Nodulisporium sp. and found to have chlorosis activity, which was stronger against monocotyledons than against dicotyledons [12]. Helvetica Chimica Acta ± Vol.…”

“…Comparison of the physicochemical properties with reported data allowed to identify the compounds 1, 4, and 5, isolated from the same fungus, as 2,3-dihydro-5-hydroxy-2-methyl-4H-1-benzopyran-4-one [2] [11], 3,5-dihydroxy-2-(1-oxobutyl)cyclohex-2-en-1-one [12], and pyroglutamic acid ( 5-oxo-l-proline) [13], respectively. Compound 1 was reported as a metabolite from the rice culture solution of the fungus Phialophora gregata and shown to have biological activity against soybean cells [11].…”

Macrocarpones, novel metabolites from stromata of Hypoxylon macrocarpum, and new evidence on the chemotaxonomy of Hypoxylon species

“…Some collections of H. fuscum were found to contain minor quantities of the benzophenone Daldinal A (10), which had so far only been encountered in Daldinia species. (IGARASHI et al 1993), i.e., a typical Xylariaceae anamorph. Apart from particular Daldinia species, this compound has never before been isolated from Hypoxylon species or any other fungus.…”