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Callose and β‐1,3‐glucanase inhibit Phytophthora cinnamomi in a resistant avocado rootstock
Author(s) -
van den Berg N.,
Christie J. B.,
Aveling T. A. S.,
Engelbrecht J.
Publication year - 2018
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/ppa.12819
Subject(s) - phytophthora cinnamomi , callose , biology , rootstock , zoospore , phytophthora cactorum , plant disease resistance , botany , phytophthora , inoculation , haustorium , pathogen , root rot , defence mechanisms , horticulture , microbiology and biotechnology , cell wall , spore , host (biology) , ecology , biochemistry , gene
Phytophthora root rot ( PRR ) of avocado, caused by Phytophthora cinnamomi , is a significant threat to sustainable production wherever the crop is grown. Resistant rootstocks in combination with phosphite applications are the most effective options for managing this disease. Recently, the mechanisms underpinning PRR resistance have been investigated by the avocado community. Here, biochemical assays and confocal and scanning electron microscopy were used to investigate early defence responses in PRR resistant and ‐susceptible avocado rootstocks. Zoospore germination and subsequent hyphal growth for the pathogen were significantly inhibited on the surface of resistant avocado roots. When penetration occurred in the resistant R0.06 rootstock, callose was deposited in the epidermal cells, parenchyma and cortex of roots. In addition, β‐1,3‐glucanase was released early (6 h post‐inoculation, hpi) in response to the pathogen, followed by a significant increase in catalase by 24 hpi. In contrast, susceptible R0.12 roots responded only with the deposition of lignin and phenolic compounds incapable of impeding pathogen colonization. In this study, PRR resistance was attributed to a timely multilayered response to infection by P. cinnamomi .