Chemotaxis of Actinoplanes missouriensis Zoospores to Fungal Conidia, Chlamydospores and Sclerotia

Abstract

The chemotactic response of Actinoplanes missouriensis zoospores to three different types of fungal spores (conidia of Curvularia lunata, chlamydospores of Fusarium solani and sclerotia of Macrophominaphaseolina) and their exudates was examined in vitro and in soil. Zoospores were attracted in vitro to substances exuded by fungal spores and to a number of organic compounds but not to sodium phosphate buffer solution. Numbers of zoospores attracted to spores of C . lunata, F. solani or M . phaseolina and their exudates, mixed in a sterilized soil, were significantly (P = 0.05) greater than to soil only supplemented with buffer. Movement of zoospores in an unsterilized soil to conidia, chlamydospores or sclerotia was significantly greater (P = 0.05) than background populations occurring in soil held at 0, -10 and -50 mbar matric potential. Attraction of zoospores to fungal spores and (or) their exudates was generally in the order of conidia > chlamydospores > sclerotia both in vitro and in soil. The results suggest that compounds exuded by living fungal spores may act as attractant for motile Actinoplanes zoospores.

Zinc Improves Biocontrol of Fusarium Crown and Root Rot of Tomato by Pseudomonas fluorescens and Represses the Production of Pathogen Metabolites Inhibitory to Bacterial Antibiotic Biosynthesis

“…This is perhaps the first evidence that pathogens can have a direct impact on the mechanism(s) of action of biocontrol agents. Previously, fungal pathogens have been shown to have a selective influence, positive and negative, on the proliferation of bacterial biocontrol agents in the rhizosphere of wheat (24) and to influence bacterial chemotaxis (2).…”

Microbial dispersal in unsaturated porous media: Characteristics of motile bacterial cell motions in unsaturated angular pore networks

“…PNM, d=0.5μm PNM, d=1μm PNM, d=2.5μm Brockman et al, 2004Wang & Griffin, 1976Arora, 1986Issa et al, 1993Bashan & Levanony, 1987 (mm 2 /s) Figure 8. Effect of hydration condition on bacterial chemotactic sensitivity coefficient as a function of matric potential: comparison with experimental data available for soil bacterial species with chemotactic movement (Wong and Griffin [1976], Arora [1986], Bashan and Levanony [1987], Issa et al [1993], andBrockman et al [2004] for accusand samples with mean grain size of 0.53 mm) d denotes simulated bacterial cell size chosen from observed range of bacterial cell sizes in soil [Portillo et al, 2013]. The bacterial cell velocity is chosen to be 60 lm/ s from observed average swimming motility for many bacterial cells [McCarter, 2005].…”

Complete genome sequence of the motile actinomycete Actinoplanes missouriensis 431T (= NBRC 102363T)

“…Released zoospores have chemotactic properties for several substrate types, including sugars, amino acids, aromatic compounds and mineral ions [6,7]. Flagella of the zoospores consist of a 44-kDa flagellar protein (FliC) [5] encoded by the fliC gene, which has been applied as a molecular marker in a taxonomic study of the genus Actinoplanes [8].…”

“…The genus is of morphological interest because its members typically produce spherical, subspherical, cylindrical, or very irregular sporangia arising from vegetative mycelia [1,4]. Sporangiospores, which are released following the immersion of sporangia in water, are motile by means of polar or peritrichous flagella [5] and display a positive chemotactic response to a number of amino acids, aromatic compounds, sugars and inorganic ions [6,7]. Recently, the flagellin gene of various Actinoplanes strains was successfully amplified and sequenced to reveal the evolutionary relationships between flagellar genes [8].…”