Sucrose-Mediated Priming of Plant Defense Responses and Broad-Spectrum Disease Resistance by Overexpression of the Maize Pathogenesis-Related PRms Protein in Rice Plants

Abstract

Expression of pathogenesis-related (PR) genes is part of the plant's natural defense response against pathogen attack. The PRms gene encodes a fungal-inducible PR protein from maize. Here, we demonstrate that expression of PRms in transgenic rice confers broad-spectrum protection against pathogens, including fungal (Magnaporthe oryzae, Fusarium verticillioides, and Helminthosporium oryzae) and bacterial (Erwinia chrysanthemi) pathogens. The PRms-mediated disease resistance in rice plants is associated with an enhanced capacity to express and activate the natural plant defense mechanisms. Thus, PRms rice plants display a basal level of expression of endogenous defense genes in the absence of the pathogen. PRms plants also exhibit stronger and quicker defense responses during pathogen infection. We also have found that sucrose accumulates at higher levels in leaves of PRms plants. Sucrose responsiveness of rice defense genes correlates with the pathogen-responsive priming of their expression in PRms rice plants. Moreover, pretreatment of rice plants with sucrose enhances resistance to M. oryzae infection. Together, these results support a sucrose-mediated priming of defense responses in PRms rice plants which results in broad-spectrum disease resistance.

Trichoderma gamsii affected herbivore feeding behaviour on Arabidopsis thaliana by modifying the leaf metabolome and phytohormones

“…Sugars are essential for plant growth and development due to their roles as carbon and energy sources, signals and putative defence priming agents (Koch, 2004; Gomez‐Ariza et al ., 2007). T. gamsii F18 may mediate the T. ni feeding behaviour by diminishing the attractiveness of the insect for primary metabolites such as sugars (Juniper and Richard, 1986).…”

Do the seeds of Solidago gigantea Aiton have physiological determinants of invasiveness?

“…In the analyzed seeds, the high sucroseto-hexose ratio could switch the specific sucrose signal to the induction of genes encoding the synthesis of secondary metabolites involved in defense responses (Kwon et al 2011). Sucrose, the most abundant disaccharide in S. gigantea seeds, is presently regarded as the prime candidate for a signal molecule in the innate immunity of plants (Gómez-Arisa et al 2007). An effective stress response is probably possible due to coordinated interactions between hormone and sugar signaling pathways.…”

The role of sugar signaling in plant defense responses against fungal pathogens

“…They probably function as priming molecules leading to pathogen-associated molecular patterns (PAMP)-triggered immunity and effector-triggered immunity in plants ( Gómez-Ariza et al 2007;Bolouri Moghaddam and Van den Eden 2012). This novel concept of ''sweet priming'' predicts specific key roles to saccharides in perceiving, mediating and counteracting both biotic and abiotic stresses (Bolouri Moghaddam and Van den Eden 2012) (Fig.…”

“…Primed plants show fast and/or strong activation of defence responses when subsequently challenged by microbes, insects, or abiotic stress'' (Conrath 2011). According to the above definition, priming is caused by a wide range of agents, including also the proposed sucrose (Gómez-Ariza et al 2007; Bolouri-Moghaddam and Van den Ende 2012). Exogenously applied sucrose induced accumulation of the transcript of PR proteins (PR-2 and PR-5) in Arabidopsis thaliana (Thibaud et al 2004).…”