Effects of different classes of attractants, cochliophilin A and <i>N</i>-(<i>E</i>)-feruloyl-4-<i>O</i>-methyldopamine, on the response of <i>Aphanomyces cochlioides</i> zoospores in their chemoattraction and activation of motility linked with intracellular cAMP

Abstract

Cochliophilin A (5-hydroxy-6,7-methylenedioxyflavone, 1) and N-(E)-feruloyl-4-O-methyldopamine (2) are naturally occurring host-specific chemoattractants for Aphanomyces cochlioides zoospores. In a cross-competition assay, compound 1 (4 fmol) applied to diatomite particles clearly attracted A. cochlioides zoospores in an aqueous solution of excessive compound 2 (1×10 −6 M) that could mask a concentration gradient of 1 dispersed from the particles. Similarly, 2 (40 fmol) on particles also attracted A. cochlioides zoospores in an aqueous solution of 1 (1×10 −6 M). In addition, compound 2 on the particles did not attract the zoospores in an aqueous solution containing 1×10 −6 M NADP + , while 1 clearly attracted zoospores in the same solution. These results allowed us to speculate that compounds 1 and 2 do not share receptors. The chemosensory system for 1 is probably for host recognition of A. cochlioides zoospores, while the system for 2 is linked to cell differentiation.

Studies on the metabolic regulation of denitrifying bacteria and phytopathogenic microorganisms using chemical agents found in chemical ecology-based phenomena

“…Among them, Pseudomonas jessenii strain EC-S101 isolated from a spinach root administered an induction of unique hyperbranching toward A. cochlioides mycelia. 20) To isolate this hyperbranch-inducing factor and elucidate its chemical structure, we first attempted a shake culture of P. jessenii strain EC-S101 in potato-dextrose broth medium at a scale of several liters. However, neither the concentrated culture fluid thus obtained nor the extract showed any hyphal hyperbranchinducing activity.…”