Cold-induced changes in cell wall stability determine the resistance of winter triticale to fungal pathogen Microdochium nivale

Abstract

The exposure of winter triticale to cold promotes genotype-dependent resistance to fungal pathogen. We present the evidence that structural and chemical modifications of the cell wall components induced by cold can be correlated with the resistance against fungal infection. Our results showed that cellulose of hardened triticale cv. Hewo (able to develop resistance after cold treatment) has more compact and integrated structure, thicker and longer fibres when compared to cv. Magnat (susceptible to fungal infection despite plant hardening). Such structure of cellulose limits water sorption, favours stronger bonding the water of crystallisation to macromolecules, impedes depolymerisation process during decomposition, and finally results in higher thermal stability of cell wall. Furthermore, the lignin composition is drastically modified in resistant plants. Pattern of the thermal decomposition indicates higher molecular mass and more complex structure of lignin, followed by the higher thermal stability. We conclude that specific structure of lignocellulosic cell wall of the resistant plants forms a barrier for fungal enzymes digesting host tissue as well as can resist better the mechanical pressure of hyphae.

Electrical Signaling, Photosynthesis and Systemic Acquired Acclimation

“…However, there could be also another scenario and plant strategy to communicate different stimuli and induce the systemic responses to local stress. In some cases, a cross-talk is seen, in which one type of locally applied stress is capable of generating a protective response or acclimation to another type of biotic or abiotic stress (Mühlenbock et al, 2008 ; Szechyńska-Hebda et al, 2015 , 2016a , b ; Czarnocka et al, 2017 ). The environmental factors, like a sudden increase in light intensity, changes in temperature, limitation in water accessibility, or pathogen attack, all of them depress efficiency of CO 2 assimilation due to reduction of stomatal conductance, but do not limit foliar absorption of light energy (Müller et al, 2001 ; Mullineaux and Karpiński, 2002 ; Holt et al, 2004 ; Baker, 2008 ).…”

Effect of a Bacillus subtilis strain on flax protection against Fusarium oxysporum and its impact on the root and stem cell walls

“…This was also observed in plants inoculated with B. subtilis or with both B. subtilis and Fol at 8 dpi (Figure 8). Similarly, Szechyńska‐Hebda, Hebda, Mirek, and Miernik (2016) have shown a higher thermal stability (increase of temperatures and a decrease of residual mass) of cellulose and lignin extracted from leaves of triticale plants more resistant to fungal infection as compared to the sensitive ones.…”

Local and systemic regulation of PSII efficiency in triticale infected by the hemibiotrophic pathogen Microdochium nivale

“…Physical barriers, i.e. the hydrophobic cuticle on the leaf surface or lignin in the cell wall (Szechyńska‐Hebda et al , Abdelhalim et al ), result in leaf tissue resistance to the mechanical and enzymatic forces of fungal hyphae and can thus define fungal behaviour (Szechyńska‐Hebda et al , ). These mechanisms can discriminate between the resistance and susceptibility of a plant infected with a weakly pathogenic fungus.…”

“…Some of these changes are also thought to increase resistance to pathogens, e.g. cellular dehydration, accumulation of defence‐related proteins and fructans and changes in the physical and chemical properties of the leaf surface and cell walls (Szechyńska‐Hebda et al , , , Kovi et al ). The lower number of QTL regions corresponding to the resistance of unhardened plants also confirms that effective defence can be developed only after cold treatment.…”

“…Samuels & Hallett, previously named Fusarium nivale (Tronsmo et al ), is a psychrotrophic fungal pathogen that causes pink snow mould on Poaceae. Microdochium nivale is able to infect crowns and leaves, either under snow or during rainy winter weather (Szechyńska‐Hebda et al , ). The first disease symptoms appear on the leaves as patches of pinkish‐white mycelium.…”