Open AccessApplication of glycerol as a foliar spray activates the defence response and enhances disease resistance of T heobroma cacao
Author(s) -
Zhang Yufan,
Smith Philip,
Maximova Siela N.,
Guiltinan Mark J.
Publication year - 2015
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.12158
Subject(s) - glycerol , theobroma , biology , endogeny , chlorosis , pathogenesis related protein , phytophthora palmivora , reactive oxygen species , inducer , biochemistry , botany , gene expression , gene , phytophthora
Summary Previous work has implicated glycerol‐3‐phosphate ( G3P ) as a mobile inducer of systemic immunity in plants. We tested the hypothesis that the exogenous application of glycerol as a foliar spray might enhance the disease resistance of T heobroma cacao through the modulation of endogenous G3P levels. We found that exogenous application of glycerol to cacao leaves over a period of 4 days increased the endogenous level of G3P and decreased the level of oleic acid (18:1). Reactive oxygen species ( ROS ) were produced (a marker of defence activation) and the expression of many pathogenesis‐related genes was induced. Notably, the effects of glycerol application on G3P and 18:1 fatty acid content, and gene expression levels, in cacao leaves were dosage dependent. A 100 m m glycerol spray application was sufficient to stimulate the defence response without causing any observable damage, and resulted in a significantly decreased lesion formation by the cacao pathogen P hytophthora capsici ; however, a 500 m m glycerol treatment led to chlorosis and cell death. The effects of glycerol treatment on the level of 18:1 and ROS were constrained to the locally treated leaves without affecting distal tissues. The mechanism of the glycerol‐mediated defence response in cacao and its potential use as part of a sustainable farming system are discussed.