Induced accessibility and enhanced inaccessibility at the cellular level in barley XVI. The accessibility-associated factor(s) induced in barley coleoptiles inoculated with Blumeria graminis f. sp. hordei

摘要

It was examined whether successful infection by Blumeria (syn. Erysiphe) graminis f. sp. hordei (a pathogen) induced production of some chemical factors which could explain the accessible state of coleoptile cells of barley. Water-soluble extracts were prepared from coleoptiles 0, 6, 12, 18 hr after inoculation with B. graminis and uninoculated coleoptiles. Coleoptiles whose lower surfaces were treated with these extracts, were inoculated with Erysiphe pisi (a nonpathogen), and its penetration efficiency (PE) was examined. This nonpathogenic fungus formed haustoria at a significantly high PE level only in the coleoptiles treated with extracts of the B. graminis.inoculated coleoptiles prepared at 18 hr after inoculation but not with those extracted earlier than 12 hr. These results suggested that some chemical factors might be produced in coleoptiles by 18 hr after inoculation of B. graminis, at the time of incipient development of its haustoria. In thin layer chromatography of the extracts, a bluish fluorescence under UV light and a ninhydrin-positive spot was detected at position Rf =0.61. The fraction containing this spot and two other fractions which were not detected by UV or the ninhydrin reaction had accessibility-inducing activity, suggesting that some of these factors may associate mutually to induce accessibility in coleoptile cells.