Arbuscular mycorrhizal (AM) fungi enhance terrestrial plant growth by forming a symbiotic relationship with the roots of its host plant. Effects of red and green algal extracts on in vitro hyphal growth of AM fungi, Gigaspora margarita and Glomus caledonium, and on the mycorrhizal development and growth of papaya seedlings and passionfruit cuttings were investigated. Three kinds of red algae, Gracilaria verrucosa, Gelidium amansii and Eucheuma cottonii, and a green alga, Chlorella pyrenoidosa, were extracted with 75% methyl alcohol (MeOH), and these extracts were fractionated by a flash chromatograph equipped with an octa decyl silane column and eluted with 0, 10, 25, 50, and 100% MeOH. Twenty‐five percent MeOH fractions (25% MeOH eluates) of each type of alga most significantly increased in vitro hyphal growth of AM fungi. Inhibition of AM hyphal growth was not observed in any of the fractioned MeOH eluates. Root colonization of papaya and of passionfruit were markedly stimulated by the application of the 25% MeOH eluates of red and green algal extracts. The growth of these plants were promoted in comparison to the control. These results suggest that red and green algae not only contain AM stimulatory substances, but also contribute to mycorrhizal development in higher plants.
A compound that stimulated the growth of an arbuscular mycorrhizal (AM) fungus was isolated from 75% methyl alcohol (MeOH) extracts of a brown alga, Laminaria japonica Areschoug, using high-pressure liquid chromatography (HPLC). This compound (Compound 1) was identified as mannitol by HPLC and nuclear magnetic resonance (NMR) spectroscopy. Compound 1 and purchased polysaccharides (alginic acid, fucoidan, carrageenan and mannan from marine algae) were tested for in vitro hyphal growth of an AM fungus, Gigaspora margarita Becker and Hall. Compound 1 (50-500 mg L )1 ) and carrageenan (1000 mg L )1 ) significantly stimulated the hyphal growth of germinating spores of Gi. margarita. The application of 100 mg L )1 of Compound 1 to trifoliate orange (Poncirus trifoliata Raf.) inoculated with Gi. margarita promoted root colonization and increased plant growth. These results suggest low concentrations of mannitol are among the reasons for enhanced hyphal growth and root colonization by the application of algal extracts. Other sugar alcohols (100-300 mg L )1 of xylitol, sorbitol and meso-erythritol) also increased the hyphal growth of Gi. margarita.
Arbuscular Mycorrhizal (AM) fungi enhance terrestrial plant growth by forming a symbiotic relationship with the roots of its host plant. A growth stimulant for AM fungi was isolated from a brown alga Laminaria japonica Areschoug. The active substance for in vitro AM hyphal growth was isolated from 75% methanol extracts of L. japonica using a succession of chromatographic procedures, including flash chromatography equipped with an octa decyl silane (ODS) column, gel filtration chromatography and HPLC using an ODS column. Spores of Gigaspora margarita Becker & Hall, an AM fungus, were exposed to the compound in vitro, and hyphal growth of G. margarita was measured after two weeks of incubation. At 40 mg L −1 , the compound significantly stimulated the in vitro hyphal growth of G. margarita, compared to the K. Kuwada ( ) · M. Utamura control. This compound was elucidated as 5 -deoxy-5 -methylamino-adenosine by EIMS and NMR spectrum.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.