The chemical inducer, BTH (benzothiadiazole) and root colonization by mycorrhizal fungi (Glomus spp.) trigger resistance against white rot (Sclerotinia sclerotiorum) in sunflower

Abstract

White rot caused by Sclerotinia sclerotiorum (SS) is one of the most devastating plant diseases of sunflower. Controlling this pathogen by available tools hardly result in acceptable control. The aim of this study was to elucidate the effects of plant resistance inducers, BTH (benzothiadiazole in Bion 50 WG) and arbuscular mycorrhizal fungi (AMF) on disease development of white rot in three sunflower genotypes. Defence responses were characterized by measuring the disease severity and identifying cellular/ histological reactions (e.g. autofluorescence) of host plants upon infection. Depending on the host genotype, a single application of inducers reduced disease symptoms. Histological examination of host responses revealed that BTH and/or AMF pre-treatments significantly impeded the development of pathogenic hyphae in Iregi szürke csíkos and P63LE13 sunflower plants and it was associated with intensive autofluorescence of cells. Both localized and systemic induction of resistance was observed. Importantly, the frequency of mycorrhization of hybrid P63LE13 and PR64H41 was significantly increased upon BTH treatment, so it had a positive effect on the formation of plant-mycorrhiza interactions in sunflower. To our knowledge, this is the first report on the additive effect of BTH on mycorrhization and the positive effect of these inducers against SS in sunflower.

Potential of Biotic and Abiotic Inducers of Eliciting Systemic Resistance in Snap Bean (Phaseolus vulgaris L.) in Controlling Rust Caused by Uromyces appendiculatus

“…Iriti and Faoro, (2003) showed that in bean cultivars against rust (Uromyces appendiculatus) Bion induce resistance and controlled the bean rust over all the tested cultivars. The same was obtained by Guo and Stotz, 2007;Azami-Sardooei et al (2013) and Bán et al (2017) who indicated that foliar applications of Bion reduced B. cinerea on cucumber and sunflower and white mold (S. sclerotiorum) disease on bean besides both systemic and localized inductions of resistance were observed. Gaffney et al (1993); Sticher et al (1997) and Kumar, (2014) reported that Salicylic acid (SA) plays an important role in the induction of plant defense as plant hormone against plant diseases via various host-pathogen interactions.…”

Systemic Resistance in Snap Bean (Phaseolus vulgaris L.) Elicited by Some Chemicals and Biotic Inducers Against White Mold Disease Caused by Sclerotinia sclerotiorum

“…Azami-Sardooei et al (2013) investigated the effects of foliar applications of different concentrations of BTH on resistance to B. cinerea on bean and cucumber, only concentrations of 250 mg/l and higher, strongly reduced susceptibility against B. cinerea. Recently, Bán et al (2017) found that the application of Bion reduced sunflower white mold (S. sclerotiorum) disease symptoms; besides both localized and systemic inductions of resistance were observed. Salicylic acid (SA) is a phenolic plant hormone which plays an important role in regulating defenses in plants against biotrophic and hemibiotrophic pathogens, however signaling pathways mediated by salicylic acid (SA) are widely studied in various hostpathogen interactions (Gaffney et al, 1993 andSticher et al, 1997).…”

Signals and Machinery for Mycorrhizae and Cereal and Oilseed Interactions towards Improved Tolerance to Environmental Stresses

“…AMF compete with pathogenic fungi for colonization sites, space, and photosynthesis. Similarly, Bán et al [ 120 ] showed that the inoculation with AMF belonging to the Glomus genus led to localized and systemic resilience to white rot ( Sclerotinia sclerotiorum ) in sunflower.…”