Flux of nitric oxide between the necrotrophic pathogen Botrytis cinerea and the host plant

Abstract

Nitric oxide (NO) production by Botrytis cinerea and the effect of externally supplied NO were studied during saprophytic growth and plant infection. Fluorescence analysis with 4,5-diaminofluorescein diacetate and electrochemical studies were conducted in vitro between 4 and 20 h of incubation and in planta between 15 and 75 h post-inoculation. The production of NO by B. cinerea in vitro was detected inside the germinating spores and mycelium and in the surrounding medium. In planta production of NO showed a large variation that was dependent on the host plant and developmental stage of the infection. The induced production of NO was detected from 16 h of in vitro incubation in response to externally added NO. The production of NO by B. cinerea is probably modulated to promote fungal colonization of the plant tissue. The production of NO which diffuses outside the fungal cells and the induction of NO production by exogenous NO open up the possibility of NO cross-talk between the fungus and the plant. Finally, the existence of an NO concentration threshold is proposed, which may increase or reduce the plant defence against necrotrophic fungal pathogens.

Nitric oxide: an effective weapon of the plant or the pathogen?

“…The organisms cope with a broad range of potential NO sources, which appear to be reductive or oxidative in operation. Fungi do not contain NOS‐like sequences in their genomes, except for some fungal species from the genus Aspergillus ( A. flavus , A. oryzae and A. niger ) and Glomerella graminicola (Turrion‐Gomez and Benito, ). However, it has been suggested that NO synthesis in fungi is derived from an l ‐arginine‐dependent pathway using a complex NOS‐like system.…”

“…However, L‐NAME applied to the necrotroph Botrytis cinerea growing on medium as well as in planta did not diminish the production of NO (Turrion‐Gomez and Benito, ). Moreover, when searching for the source of NO production through NR, B. cinerea was incubated with NO 3 − ; however, no NO signal was detected, suggesting that a physiological and genetic system other than NOS and NR is responsible for NO production in this pathogen (Turrion‐Gomez and Benito, ).…”

Nitric oxide in plants: an assessment of the current state of knowledge

“…For example, the virulence factor cryptogein produced by the oomycete Phytophthora cryptogea aids pathogenesis by promoting host cell death via NO generation (Foissner et al 2000; Lamotte et al 2004). In addition, pathogen-generated NO can promote the formation of key fungal infection structures (Prats et al 2008; Turrion-Gomez and Benito 2011). Thus, depending on the pathogenic lifestyle, NO can act as either a pathogen virulence or a host defence factor (Perchepied et al 2010; Turrion-Gomez and Benito 2011; Mur et al 2012; Rasul et al 2012).…”

“…This poses a question that is not only relevant to plant pathology: How exactly could NO fulfil these very different roles? It seems probable that the relative concentration of NO is important (Beligni and Lamattina 1999; Turrion-Gomez and Benito 2011) but equally, cell-, tissue- or organelle-specific roles are vital, reflecting interactions with differing components and signalling pathways.…”

A gomba eredetű elicitor kitozán hatása a zárósejtek működésére: a sztómamozgás és a zárósejt fotoszintézisének kapcsolata

“…Ugyanis részt vesz a PTI és a védekezési válaszreakciók kialakításában, képes a HR kiváltására, valamint képes a szimbiózisok kialakulását elősegíteni. Hogy mi állhat ezen ellentmondásos hatások hátterében jelenleg még nem ismert, azonban feltételezhetően az eltérő folyamatok indukciójáért a NO koncentráció-függő hatásmechanizmusa tehető felelőssé [102,103].…”