Low temperature‐wheat‐fungal interactions: A carbohydrate connection

Abstract

Winter annual and perennial crop species grown in the northern boreal ecosystem must survive periods of protracted snow cover and low temperatures during the winter. In deep snow regions, plants are susceptible to winter stresses caused by both snow molds and low temperatures. Therefore, high levels of tolerance to freezing and snow molds are requisite for crops adapted to these regions. Accumulation of soluble carbohydrates in winter wheat during the autumn is linked to both hardening and resistance to attack by snow molds. Snow mold‐resistant cultivars accumulate higher levels of carbohydrate and metabolize them at slower rates than susceptible cultivars. The quantity and quality of carbohydrates, particularly fructans, remaining in the spring after snow mold attack appear important for survival of winter wheat. However, the total accumulation of carbohydrates is dependent on the stage of development of the winter cereal plant at the beginning of the winter. Recent research findings have shown that sugars are pivotal metabolic activators of the sugar‐sensing enzyme, hexokinase, which initiates signal transduction and activation of numerous metabolic genes including host defense genes. Thus, an understanding of the metabolism of soluble carbohydrates, particularly fructans, during plant growth, hardening, and snow mold infection, is essential to the elucidation of survival mechanisms in plants subjected to these winter stresses.

Influence of Climate Changes on Wheat Viruses Variability in Ukraine

“…However, often the manifestation of the adaptive reaction of the plant to the action of environmental factors is similar to the manifestation of pathologies caused by infectious defeat of the plant organism. In 1999, 2001and 2006in Poltava, Ivano-Frankivsk, Kyiv regions, and in Khmelnytsky region (2006, we found winter wheat plants with purple flag leaves, which are similar to the symptoms caused with BYDV. It was found that these symptoms are caused by both viral infections and extreme weather conditions (a sharp drop in the air temperature in the phase of the output of the tube) (Reshetnyk, 2010).…”

Ecotypic variation of water-soluble carbohydrate concentration and winter hardiness in cocksfoot (Dactylis glomerata L.)

“…The fructan concentration of foliage and stubble in autumn showed a positive correlation with winter hardiness and snow endurance but no correlation with snow mold resistance. The WSC in grasses and cereals has been found to be related with freezing tolerance and snow mold resistance during autumn and winter (Shibata & Shimada 1986;Suzuki 1989;Gaudet et al 1999). The fructan concentrations have been more closely related with snow mold resistance than the mono and disaccharide concentrations in wheat (Triticum aestivum L.) (Yoshida et al 1998).…”

“…However, the variation of winter hardiness among ecotypes collected in diverse countries and the relationship between WSC concentration and the geographic origins of these ecotypes have not been reported in cocksfoot. Snow mold resistance in cereals was closely correlated with WSC in autumn and was especially related to fructan concentration (Gaudet et al 1999). It was well known that the winter hardiness of cocksfoot was lower than that of timothy and meadow fescue (Festuca pratensis Huds.…”

Increased Cell-Wall Mass and Resistance to Freezing and Snow Mold during Cold Acclimation of Winter Wheat under Field Conditions

“…4). The content of stored carbohydrates such as fructan provide a long-term supply of respiratory energy to plants under snow cover and increases the tolerance of plants to snow mold attack (Gaudet et al, 1999).…”

“…Although freezing injury and snow mold damage are derived from different physiological mechanisms (Hofgaard et al, 2003), cold acclimation enhances resistance to freezing and snow mold. Accumulation of soluble carbohydrates is an important physiological mechanism that enhances resistance to freezing and snow mold (Levitt, 1972;Yoshida et al, 1998;Gaudet et al, 1999;Wanner and Junttila, 1999). However, because the cold acclimation process involves altered expression of many genes and corresponding biochemical and physiological changes (Thomashow, 1998), many physiological changes, in addition to accumulation of soluble sugars, are involved in enhanced resistance to freezing and snow mold.…”