Dynamics of growth regulators during infection of

Authors: Y Chen C Zhang P Cong

Publish Date: 2012/03/16

Volume: 41, Issue: 3, Pages: 247-253

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Abstract

Alternaria blotch of apple caused by Alternaria alternata apple pathotype has a severe negative effect on apple production It can cause tissue necrosis on leaves young shoots and fruit Recent studies on this pathogen have mostly focused on phytotoxicity and pathogenicity There are few reports on the roles of signaling and metabolism in the process of infection In this paper a filial generation with substantial differences in resistance between individuals with similar genetic background was used as a host An aggressive strain of A alternate that can complete the infection process 72 h after inoculation served as the pathogen A reproducible and reliable in vitro inoculation system for plant growth regulator determination was established to overcome the difficulties of inoculation of attached leaves Alterations in growth regulator concentrations were detected including indole3acetic acid IAA zeatin riboside ZR gibberellin A3 GA3 abscissic acid ABA and the polyamines putrescine Put spermidine Spd and spermine Spm Results indicated the plant growth regulators interacted with each other to modulate signaling and metabolic networks A biotrophiclike phase was inferred to exist before necrosis developed Gibberellin A3 and ABA appeared to be involved in the phase transformation from the biotrophiclike stage to the necrotrophic stage Cytokinin Put and Spd appeared to be related to disease resistance This study advances our knowledge of the pathological mechanisms of Alternaria blotch on apple and provides useful resources for development of disease control and prevention

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