Fighting Asian Soybean Rust

Langenbach, Caspar; Campe, Ruth; Beyer, Sebastian F.; Mueller, André N.; Conrath, Uwe

doi:10.3389/fpls.2016.00797

Cited by 86 publications

(79 citation statements)

References 155 publications

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“…Therefore, currently the most effective control for ASR is fungicide application which may cost up to $25 per acre but varies every year (Livingston et al, 2004). However, insensitivity to fungicides is also increasing in Pp because of the evolution of more resistant strains, especially in South America where Pp poses a major threat (Langenbach et al, 2016). Therefore, there is a need to find alternative strategies or integrated approaches to the control of ASR.…”

Section: Introductionmentioning

confidence: 99%

Transcriptome‐based analyses of phosphite‐mediated suppression of rust pathogens Puccinia emaculata and Phakopsora pachyrhizi and functional characterization of selected fungal target genes

et al. 2018

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Phosphite (Phi) is used commercially to manage diseases mainly caused by oomycetes, primarily due to its low cost compared with other fungicides and its persistent control of oomycetous pathogens. We explored the use of Phi in controlling the fungal pathogens Puccinia emaculata and Phakopsora pachyrhizi, the causal agents of switchgrass rust and Asian soybean rust, respectively. Phi primes host defenses and efficiently inhibits the growth of P. emaculata, P. pachyrhizi and several other fungal pathogens tested. To understand these Phi-mediated effects, a detailed molecular analysis was undertaken in both the host and the pathogen. Transcriptomic studies in switchgrass revealed that Phi activates plant defense signaling as early as 1 h after application by increasing the expression of several cytoplasmic and membrane receptor-like kinases and defense-related genes within 24 h of application. Unlike in oomycetes, RNA sequencing of P. emaculata and P. pachyrhizi did not exhibit Phi-mediated retardation of cell wall biosynthesis. The genes with reduced expression in either or both rust fungi belonged to functional categories such as ribosomal protein, actin, RNA-dependent RNA polymerase, and aldehyde dehydrogenase. A few P. emaculata genes that had reduced expression upon Phi treatment were further characterized. Application of double-stranded RNAs specific to P. emaculata genes encoding glutamate N-acetyltransferase and cystathionine gamma-synthase to switchgrass leaves resulted in reduced disease severity upon P. emaculata inoculation, suggesting their role in pathogen survival and/or pathogenesis.

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Section: Introductionmentioning

confidence: 99%

Transcriptome‐based analyses of phosphite‐mediated suppression of rust pathogens Puccinia emaculata and Phakopsora pachyrhizi and functional characterization of selected fungal target genes

et al. 2018

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“…The unavailability of commercial cultivars with acceptable levels of resistance to ASR and a high genetic variability of the P. pachyrhizi population are the major causes of the failure to control ASR (Yamanaka et al, 2010). Application of foliar fungicides, particularly quinone outside and demethylation inhibitors (QoIs and DMIs), has been recommended for minimizing the losses caused by ASR (Langenbach, Campe, Beyer, Mueller, & Conrath, 2016). Additionally, the use of inducers of resistance such as the Acibenzolar-S-Methyl (ASM), an analogue of the salicylic acid, could be an alternative for ASR management (Cruz, Rodrigues, Diniz, Moreira, & Barros, 2014;Cruz et al, 2013;Dallagnol, Navarini, Ugalde, Balardin, & Catellam, 2006;Duarte, Zambolim, Rodrigues, Rios, & Lopes, 2009;Rodrigues et al, 2009).…”

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confidence: 99%

Leaf gas exchange and chlorophyll a fluorescence in soybean leaves infected by Phakopsora pachyrhizi

Rios

Aucique‐Pérez

et al. 2017

Journal of Phytopathology

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Asian soybean rust (ASR), caused by Phakopsora pachyrhizi, is one of the most important foliar diseases affecting soybean production worldwide. This study aimed to investigate the photosynthetic performance (leaf gas exchange, chlorophyll (Chl) a fluorescence images and photosynthetic pigment pools) of soybean plants sprayed with Acibenzolar‐S‐Methyl (ASM) and the fungicide epoxiconazole + pyraclostrobin (Epo+Pyr) and further inoculated with P. pachyrhizi. The ASR symptoms progressed much faster on the leaves of plants from the control treatment (water spray) in comparison with the ASM and Epo+Pyr treatments. In general, the values for the leaf gas exchange parameters net carbon assimilation rate (A), stomatal conductance to water vapour (gs), internal CO2 concentration (Ci) and transpiration rate (E) increased for the infected plants sprayed with ASM or Epo+Pyr in comparison with plants from the control treatment. The values for the initial fluorescence (Fo), maximal fluorescence (Fm), maximal photosystem II quantum efficiency (Fv/Fm), effective photosystem II quantum yield (Y(II)) and quantum yield of regulated energy dissipation (Y(NPQ)) were consistently higher for the ASM and Epo+Pyr treatments in comparison with the control treatment at advanced stages of fungal infection. By contrast, the values for quantum yield of non‐regulated energy dissipation (Y(NO) were significantly lower for the ASM and Epo+Pyr treatments. The concentrations of total Chl a+b and carotenoids significantly increased for infected plants sprayed with ASM and Epo+Pyr in comparison with plants from the control treatment. The results of this study demonstrated that the spray of soybean plants with either ASM or Epo+Pyr contributed to reduce the negative effect of ASR on the photosynthesis of soybean plants.

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“…For example, natural inducers of disease resistance in soybean (e.g. beneficial microbes, plant volatiles), mycoparasites, and plant oils are reported to suppress fungal development or sporulation (reviewed by Langenbach et al, 2016a). Silicon and phosphite have both been reported to act dually by stimulating plant defence and directly inhibiting Pp, either by antagonizing fungal growth or building up a penetration barrier in the soybean cuticle (Ma and Yamaji, 2006;da Cruz et al, 2013;Gill et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

The Arabidopsis non‐host defence‐associated coumarin scopoletin protects soybean from Asian soybean rust

et al. 2019

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Summary The fungus Phakopsora pachyrhizi (Pp) causes Asian soybean rust (SBR) disease which provokes tremendous losses in global soybean production. Pp is mainly controlled with synthetic fungicides to which the fungus swiftly develops fungicide resistance. To substitute or complement synthetic fungicides in Asian soybean rust control, we aimed to identify antifungal metabolites in Arabidopsis which is not a host for Pp. Comparative transcriptional and metabolic profiling of the Pp‐inoculated Arabidopsis non‐host and the soybean host revealed induction of phenylpropanoid metabolism‐associated genes in both species but activation of scopoletin biosynthesis only in the resistant non‐host. Scopoletin is a coumarin and an antioxidant. In vitro experiments disclosed fungistatic activity of scopoletin against Pp, associated with reduced accumulation of reactive oxygen species (ROS) in fungal pre‐infection structures. Non‐antioxidant and antioxidant molecules including coumarins with a similar structure to scopoletin were inactive or much less effective at inhibiting fungal accumulation of ROS and germination of Pp spores. When sprayed onto Arabidopsis leaves, scopoletin also suppressed the formation of Pp pre‐infection structures and penetration of the plant. However, scopoletin neither directly activated defence nor did it prime Arabidopsis for enhanced defence, therefore emphasizing fungistatic activity as the exclusive mode of action of scopoletin against Pp. Because scopletin also protected soybean from Pp infection, the coumarin may serve as a natural fungicide or as a lead for the development of near‐to‐nature fungicides against Asian soybean rust.

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Fighting Asian Soybean Rust

Cited by 86 publications

References 155 publications

Transcriptome‐based analyses of phosphite‐mediated suppression of rust pathogens Puccinia emaculata and Phakopsora pachyrhizi and functional characterization of selected fungal target genes

Transcriptome‐based analyses of phosphite‐mediated suppression of rust pathogens Puccinia emaculata and Phakopsora pachyrhizi and functional characterization of selected fungal target genes

Leaf gas exchange and chlorophyll a fluorescence in soybean leaves infected by Phakopsora pachyrhizi

The Arabidopsis non‐host defence‐associated coumarin scopoletin protects soybean from Asian soybean rust

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