Local and systemic production of nitric oxide in tomato responses to powdery mildew infection

Abstract

Various genetic and physiological aspects of resistance of Lycopersicon spp. to Oidium neolycopersici have been reported, but limited information is available on the molecular background of the plant-pathogen interaction. This article reports the changes in nitric oxide (NO) production in three Lycopersicon spp. genotypes which show different levels of resistance to tomato powdery mildew. NO production was determined in plant leaf extracts of L. esculentum cv. Amateur (susceptible), L. chmielewskii (moderately resistant) and L. hirsutum f. glabratum (highly resistant) by the oxyhaemoglobin method during 216 h post-inoculation. A specific, two-phase increase in NO production was observed in the extracts of infected leaves of moderately and highly resistant genotypes. Moreover, transmission of a systemic response throughout the plant was observed as an increase in NO production within tissues of uninoculated leaves. The results suggest that arginine-dependent enzyme activity was probably the main source of NO in tomato tissues, which was inhibited by competitive reversible and irreversible inhibitors of animal NO synthase, but not by a plant nitrate reductase inhibitor. In resistant tomato genotypes, increased NO production was localized in infected tissues by confocal laser scanning microscopy using the fluorescent probe 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate. NO production observed in the extracts from pathogen conidia, together with elevated NO production localized in developing pathogen hyphae, demonstrates a complex role of NO in plant-pathogen interactions. Our results are discussed with regard to a possible role of increased NO production in pathogens during pathogenesis, as well as local and systemic plant defence mechanisms.

Diverse responses of wild and cultivated tomato to BABA, oligandrin andOidium neolycopersiciinfection

“…This finding might be related to a generally different extent and timing of transcript induction in the susceptible and resistant tomato genotypes. In our previous studies on these tomato genotypes, we also found differences in the extent and timing of the increased production of defence signalling molecules NO and H 2 O 2 during the time-course of powdery mildew invasion (Piterkova et al, 2009;Lebeda et al, 2014). The most remarkable difference between the genotypes studied was in the PR1 and germin-like protein classes (Fig.…”

“…BABA represents a nonprotein amino acid generally accepted as a potent priming agent conferring increased resistance to biotic and abiotic stresses in many studied plants. As model tomato genotypes, we selected the previously well-characterized highly susceptible S. lycopersicum 'Amateur', representing a domesticated inbred cultivar, and S. habrochaites that exhibits a high non-specific resistance (Mieslerova et al, 2000;Tomankova et al, 2006;Piterkova et al, 2009Piterkova et al, , 2011Lebeda et al, 2014). The defence responses were monitored as transcript-level changes of selected genes with proven roles in non-specific resistance in tomato and model plants N. tabacum or A. thaliana.…”

Resistance mechanisms of wild tomato germplasm to infection of Oidium neolycopersici

“…The key role of NO as a signal molecule and in defence processes of plants was documented in the relationships of plants to wound reaction (Orozco-Cardenas and Ryan 2002) and interactions with viruses, bacteria, oomycetes (e.g. Sedlářová et al 2011) and fungi (Tada et al 2004;Prats et al 2005;Piterková et al 2009). NO is vital for initiation and development of a hypersensitive response in plants, modification of gene expression and synthesis of PR (pathogenesis related) proteins (Wendehenne et al 2004;Zeier et al 2004;Mur et al 2006;Zaninotto et al 2006).…”

“…Experiments focused on production of ROS were followed by study of production of reactive nitrogen species (RNS), mainly NO and NO synthase-like enzyme involved in local and systemic defence responses (Piterková et al 2009), using the same three genotypes of Solanum spp., which were used for the study of ROS production (Mlíčková et al 2004). In the susceptible genotype S. lycopersicum (L. esculentum) cv.…”

“…Later attention was focused on study of resistance mechanims after infection of O. neolycopersici at the histological, biochemical and photosynthetic level (Huang et al 1998;Mieslerová et al 2004;Mlíčková et al 2004;Tománková et al 2006;Piterková et al 2009Piterková et al , 2011Prokopová et al 2010;Nožková-Hlaváčková et al, submitted). Research in the last 15 years has broadened knowledge of the genetic basis of resistance to O. neolycopersici (Lindhout et al 1994b;Ciccarese et al 1998;Huang et al 2000b;Bai et al 2003Bai et al , 2004Bai et al , 2005Li et al 2006Li et al , 2007Li et al , 2008Li et al , 2012Seifi et al 2013).…”