Trehalose induces resistance to powdery mildew in wheat

Abstract

Summary• Reduction in the degree of powdery mildew infection of wheat leaves is observed after treatments with trehalose, a nonreducing disaccharide commonly found in a wide variety of organisms, including fungi.• Wheat ( Triticum aestivum ) cv. Sideral plants grown in phytotrons were inoculated with Blumeria graminis f.sp. tritici . In addition to degree of infection, the effect of trehalose solution was further investigated using light and fluorescence microscopy and enzyme assays.• Infection in wheat leaves was reduced by 50 and 95% with trehalose solution (15 g l − 1 ) following a single spraying and three sprayings, respectively; in a detached leaf assay, trehalose was effective at concentrations as low as 0.01 g l − 1 . Trehalose did not inhibit conidial germination and differentiation of appressoria ( in vitro or on the leaf epidermis), but enhanced papilla deposition in epidermal cells. Trehalose also enhanced phenylalanine ammonia-lyase (PAL) and peroxidase (PO) activities; both markers of plant defence responses. However, the level of three cinnamyl alcohol dehydrogenase (CAD) activities (conyferyl, p -coumaryl and sinapyl alcohol dehydrogenase) was unchanged.• Trehalose treatment of wheat confers resistance to B. graminis infection by activating plant defence responses (e.g. papilla deposition, PAL and PO activities).

Gene families and evolution of trehalose metabolism in plants

“…(Müller et al 1995). Exogenous application of trehalose to plants can induce both abiotic and biotic stress responses, including transcription of genes involved in protection against oxidative stress and pathogen defence (Reignault et al 2001;Bae et al 2005aBae et al , 2005b. Exogenous trehalose derived from pathogenic and symbiotic microbes also appears to modify the metabolism of their host plants Brodmann et al 2002).…”

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

“…Trehalose is a well-known non-reducing sugar that has been shown to partially induce resistance against powdery mildew (Blumeria graminis f. sp. tritici) in wheat by the activation of phenylalanine ammonia-lyase and peroxidase genes (Reignault et al 2001;Muchembled et al 2006). Control of sugar and energy metabolism in cells regulated by sucrose non-fermenting-1-related kinase (SnRK1) is a highly important plant defense mechanism against different stresses, both biotic and abiotic (BaenaGonzalez and Sheen 2008;Hey et al 2010).…”

Criblage d\'inducteurs de réactions de défense chez le blé (<i>Triticum aestivum</i>) contre l\'oïdium (<i>Blumeria graminis f.sp. tritici</i>)

“…L'évaluation des symptômes a été faite dès leur apparition (environ 10 j après) par le comptage du nombre de colonies de Bgt. Le pourcentage de protection a été calculé par le rapport donné par Reignault et al, 2001 : …”

“…L'activation des mécanismes de défense chez la plante en réponse à la pulvérisation d'inducteurs potentiels peut être démontrée également par dosage des activités enzymatiques impliquées dans les réactions de défense du blé comme la phénylalanine ammonia lyase, les peroxydases, la cinnamoyl alcool deshydrogénase (Stadnik et Buchenauer, 2000 ;Reignault et al, 2001 ;Randoux et al, 2006 ;Renard-Merlier et al, 2007).…”