Lipid peroxidation in cotton: Xanthomonas interactions and the role of lipoxygenases during the hypersensitive reaction

Abstract

The first two authors contributed equally to this work. SummaryLipid peroxidation, often associated with hypersensitive cell death, may be initiated either by active oxygen species (AOS) or lipoxygenases (LOX). Here we report a detailed analysis of this oxidative process in both incompatible and compatible interactions between the cotton cultivar Reba B50 and Xanthomonas campestris pv. malvacearum (Xcm). The hypersensitive reaction (HR) was characterized by a massive production of polyunsaturated fatty acid (PUFA) hydroperoxides together with typical tissue dehydration. Among these, isomers peroxidized on carbon 9, largely predominant, were chiral, showing an excess in the S enantiomer. The HR process was accompanied by an increase in 9S-LOX activity and preceded by transcription of a LOX gene (GhKLox1). These results showed that: (i) AOS produced during the oxidative burst were not involved in PUFA peroxidation during HR; and (ii) as previously described in elicited leaves of tobacco, the massive enzymatic lipid peroxidation was closely associated with hypersensitive cell death. During disease development in this cotton cultivar, the 9-lipoxygenation of PUFAs was late, weak, preceded by a faint accumulation of GhKLox1 transcripts, and associated with chlorosis but not with necrosis. Consequently, the main difference between incompatible and compatible interactions was in the precocity and intensity of the oxidative process, rather than in its nature. These data provide the evidence for a correlation between lipid peroxidation and hypersensitive cell death induced by pathogens.

Coffee resistance to the main diseases: leaf rust and coffee berry disease

“…Increase in activity of phenoloxidases and its interaction with endogenous phenols have been correlated with the onset of HR (Hammerschmidt and Nicholson 1999). Lipoxygenase contributes to the HR via disruption of cell membrane lipids, to defence through the formation of toxic lipid oxidation products, as well as in the formation of lipid-derived signals (Croft et al, 1993;Jalloul et al, 2002;Montillet et al, 2005).…”

A proteomic study of Methylobacterium extorquens reveals a response regulator essential for epiphytic growth

“…As mentioned earlier, these proteins are known to be involved in coping with stress caused by electrophiles (GloA, Dps) and ROS (KatE, SodA, Dps). The latter group comprises proteins protective not only against superoxide anions and hydrogen peroxide but also alkyl hydroperoxides (see induction of Ohr and AhpC; Table 2) that are all important components of the plant defense response against microbial infection (33,41) and by-products of aerobic metabolism (see above).…”

Closely-related Xanthomonas citri subsp. citri isolates trigger distinct histological and transcriptional responses in Citrus limon

“…These compounds could produce damage in the membrane by an alternative way to the oxidative burst produced during hypersensitivity reactions (HR) of an incompatible interaction (Adam et al, 1989;Porter et al, 1995;Mittler et al, 1996). However, the LOX mechanism has been proven to be associated with plant-pathogen interaction, and has been observed in both compatible and incompatible interactions (Jalloul et al, 2002). In concordance with Chiesa et al (2013), we could say that it is possible that Xcc T inactivates ROS mechanism; nonetheless, the plant can activate another defense pathway, such as the LOX mechanism.…”