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Trujillo-Moya C, Ganthaler A, Stöggl W, Arc E, Kranner I, Schueler S, Ertl R, Espinosa-Ruiz A, Martínez-Godoy MÁ, George JP, Mayr S. Advances in understanding Norway spruce natural resistance to needle bladder rust infection: transcriptional and secondary metabolites profiling. BMC Genomics 2022; 23:435. [PMID: 35692040 PMCID: PMC9190139 DOI: 10.1186/s12864-022-08661-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 05/24/2022] [Indexed: 11/14/2022] Open
Abstract
Background Needle rust caused by the fungus Chrysomyxa rhododendri causes significant growth decline and increased mortality of young Norway spruce trees in subalpine forests. Extremely rare trees with enhanced resistance represent promising candidates for practice-oriented reproduction approaches. They also enable the investigation of tree molecular defence and resistance mechanisms against this fungal disease. Here, we combined RNA-Seq, RT-qPCR and secondary metabolite analyses during a period of 38 days following natural infection to investigate differences in constitutive and infection-induced defence between the resistant genotype PRA-R and three susceptible genotypes. Results Gene expression and secondary metabolites significantly differed among genotypes from day 7 on and revealed already known, but also novel candidate genes involved in spruce molecular defence against this pathogen. Several key genes related to (here and previously identified) spruce defence pathways to needle rust were differentially expressed in PRA-R compared to susceptible genotypes, both constitutively (in non-symptomatic needles) and infection-induced (in symptomatic needles). These genes encoded both new and well-known antifungal proteins such as endochitinases and chitinases. Specific genetic characteristics concurred with varying phenolic, terpene, and hormone needle contents in the resistant genotype, among them higher accumulation of several flavonoids (mainly kaempferol and taxifolin), stilbenes, geranyl acetone, α-ionone, abscisic acid and salicylic acid. Conclusions Combined transcriptional and metabolic profiling of the Norway spruce defence response to infection by C. rhododendri in adult trees under subalpine conditions confirmed the results previously gained on artificially infected young clones in the greenhouse, both regarding timing and development of infection, and providing new insights into genes and metabolic pathways involved. The comparison of genotypes with different degrees of susceptibility proved that several of the identified key genes are differently regulated in PRA-R, and that the resistant genotype combines a strong constitutive defence with an induced response in infected symptomatic needles following fungal invasion. Genetic and metabolic differences between the resistant and susceptible genotypes indicated a more effective hypersensitive response (HR) in needles of PRA-R that prevents penetration and spread of the rust fungus and leads to a lower proportion of symptomatic needles as well as reduced symptom development on the few affected needles. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08661-y.
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Affiliation(s)
- Carlos Trujillo-Moya
- Department of Forest Growth, Silviculture & Genetics, Austrian Research Centre for Forests BFW, Seckendorff-Gudent-Weg 8, 1131, Vienna, Austria.
| | - Andrea Ganthaler
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | - Wolfgang Stöggl
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | - Erwann Arc
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | - Ilse Kranner
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | - Silvio Schueler
- Department of Forest Growth, Silviculture & Genetics, Austrian Research Centre for Forests BFW, Seckendorff-Gudent-Weg 8, 1131, Vienna, Austria
| | - Reinhard Ertl
- University of Veterinary Medicine, VetCore Facility for Research, Veterinärplatz 1, 1210, Vienna, Austria
| | - Ana Espinosa-Ruiz
- Institute for Plant Molecular and Cell Biology (IBMCP), Consejo Superior de Investigaciones Científicas (CSIC) - Universidad Politécnica de Valencia (UPV), Valencia, Spain
| | - Maria Ángeles Martínez-Godoy
- Institute for Plant Molecular and Cell Biology (IBMCP), Consejo Superior de Investigaciones Científicas (CSIC) - Universidad Politécnica de Valencia (UPV), Valencia, Spain
| | - Jan-Peter George
- Department of Forest Growth, Silviculture & Genetics, Austrian Research Centre for Forests BFW, Seckendorff-Gudent-Weg 8, 1131, Vienna, Austria
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
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Trujillo-Moya C, Ganthaler A, Stöggl W, Kranner I, Schüler S, Ertl R, Schlosser S, George JP, Mayr S. RNA-Seq and secondary metabolite analyses reveal a putative defence-transcriptome in Norway spruce (Picea abies) against needle bladder rust (Chrysomyxa rhododendri) infection. BMC Genomics 2020; 21:336. [PMID: 32357832 PMCID: PMC7195740 DOI: 10.1186/s12864-020-6587-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 02/18/2020] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Norway spruce trees in subalpine forests frequently face infections by the needle rust fungus Chrysomyxa rhododendri, which causes significant growth decline and increased mortality of young trees. Yet, it is unknown whether trees actively respond to fungal attack by activating molecular defence responses and/or respective gene expression. RESULTS Here, we report results from an infection experiment, in which the transcriptomes (via RNA-Seq analysis) and phenolic profiles (via UHPLC-MS) of control and infected trees were compared over a period of 39 days. Gene expression between infected and uninfected ramets significantly differed after 21 days of infection and revealed already known, but also novel candidate genes involved in spruce molecular defence against pathogens. CONCLUSIONS Combined RNA-Seq and biochemical data suggest that Norway spruce response to infection by C. rhododendri is restricted locally and primarily activated between 9 and 21 days after infestation, involving a potential isolation of the fungus by a hypersensitive response (HR) associated with an activation of phenolic pathways. Identified key regulatory genes represent a solid basis for further specific analyses in spruce varieties with varying susceptibility, to better characterise resistant clones and to elucidate the resistance mechanism.
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Affiliation(s)
- Carlos Trujillo-Moya
- Federal Research and Training Centre for Forests, Landscape and Natural Hazards (BFW)-Department of Forest Genetics, Seckendorff-Gudent-Weg 8, 1131 Vienna, Austria
| | - Andrea Ganthaler
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Wolfgang Stöggl
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Ilse Kranner
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Silvio Schüler
- Federal Research and Training Centre for Forests, Landscape and Natural Hazards (BFW)- Department of Forest Growth & Silviculture, Seckendorff-Gudent-Weg 8, 1131 Vienna, Austria
| | - Reinhard Ertl
- VetCore Facility for Research, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria
| | - Sarah Schlosser
- VetCore Facility for Research, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria
| | - Jan-Peter George
- Federal Research and Training Centre for Forests, Landscape and Natural Hazards (BFW)-Department of Forest Genetics, Seckendorff-Gudent-Weg 8, 1131 Vienna, Austria
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
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Ganthaler A, Losso A, Mayr S. Using image analysis for quantitative assessment of needle bladder rust disease of Norway spruce. PLANT PATHOLOGY 2018; 67:1122-1130. [PMID: 29861507 PMCID: PMC5969058 DOI: 10.1111/ppa.12842] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
High elevation spruce forests of the European Alps are frequently infected by the needle rust Chrysomyxa rhododendri, a pathogen causing remarkable defoliation, reduced tree growth and limited rejuvenation. Exact quantification of the disease severity on different spatial scales is crucial for monitoring, management and resistance breeding activities. Based on the distinct yellow discolouration of attacked needles, it was investigated whether image analysis of digital photographs can be used to quantify disease severity and to improve phenotyping compared to conventional assessment in terms of time, effort and application range. The developed protocol for preprocessing and analysis of digital RGB images enabled identification of disease symptoms and healthy needle areas on images obtained in ground surveys (total number of analysed images n = 62) and by the use of a semiprofessional quadcopter (n = 13). Obtained disease severities correlated linearly with results obtained by manual counting of healthy and diseased needles for all approaches, including images of individual branches with natural background (R2 = 0.87) and with black background (R2 = 0.95), juvenile plants (R2 = 0.94), and top views and side views of entire tree crowns of adult trees (R2 = 0.98 and 0.88, respectively). Results underline that a well-defined signal related to needle bladder rust symptoms of Norway spruce can be extracted from images recorded by standard digital cameras and using drones. The presented protocol enables precise and time-efficient quantification of disease symptoms caused by C. rhododendri and provides several advantages compared to conventional assessment by manual counting or visual estimations.
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Affiliation(s)
- A. Ganthaler
- Department of BotanyUniversity InnsbruckSternwartestrasse 15InnsbruckA‐6020Austria
| | - A. Losso
- Department of BotanyUniversity InnsbruckSternwartestrasse 15InnsbruckA‐6020Austria
| | - S. Mayr
- Department of BotanyUniversity InnsbruckSternwartestrasse 15InnsbruckA‐6020Austria
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Ganthaler A, Stöggl W, Kranner I, Mayr S. Foliar Phenolic Compounds in Norway Spruce with Varying Susceptibility to Chrysomyxa rhododendri: Analyses of Seasonal and Infection-Induced Accumulation Patterns. FRONTIERS IN PLANT SCIENCE 2017; 8:1173. [PMID: 28713417 PMCID: PMC5492020 DOI: 10.3389/fpls.2017.01173] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 06/19/2017] [Indexed: 05/15/2023]
Abstract
Secondary phenolic metabolites are involved in plant responses to various biotic stress factors, and are apparently important for the defense against fungal pathogens. In this study, we investigated their role in defense against the rust Chrysomyxa rhododendri in Norway spruce. The fungal pathogen undergoes a seasonal lifecycle with host shift; after overwintering in rhododendron shrubs, it attacks the sprouting current-year spruce needles and causes needle fall in autumn. Repeated infections lead to reduced timber yield and severe problems with rejuvenation in subalpine Norway spruce forests. Trees with varying susceptibility to infection by C. rhododendri were selected and foliar phenolic composition was assessed using UHPLC-MS. We report on seasonal accumulation patterns and infection-related changes in the concentrations of 16 metabolites, including flavonoids, stilbenes, simple phenylpropanoids and the precursor shikimic acid, and their correlation with the infection degree of the tree. We found significant variation in the phenolic profiles during needle development: flavonoids were predominant in the first weeks after sprouting, whereas stilbenes, picein and shikimic acid increased during the first year. Following infection, several flavonoids and resveratrol increased up to 1.8 fold in concentration, whereas picein and shikimic acid were reduced by about 70 and 60%, respectively. The constitutive and early stage infection-induced concentrations of kaempferol, quercetin and taxifolin as well as the late stage infection-induced concentrations of stilbenes and picein were negatively correlated with infection degree. We conclude that a combination of constitutive and inducible accumulation of phenolic compounds is associated with the lower susceptibility of individual trees to C. rhododendri. The potentially fungicidal flavonoid aglycones may limit hyphal growth and prevent development of infection symptoms, and high levels of stilbenes may impede the infection of older needles. The presented results underline a highly compound-specific seasonal accumulation and defense response of Norway spruce and may facilitate the selection of promising trees for breeding programs.
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Affiliation(s)
- Andrea Ganthaler
- Faculty of Biology, Department of Botany, Institute of Botany, University of InnsbruckInnsbruck, Austria
- alpS – Centre for Climate Change AdaptationInnsbruck, Austria
| | - Wolfgang Stöggl
- Faculty of Biology, Department of Botany, Institute of Botany, University of InnsbruckInnsbruck, Austria
| | - Ilse Kranner
- Faculty of Biology, Department of Botany, Institute of Botany, University of InnsbruckInnsbruck, Austria
| | - Stefan Mayr
- Faculty of Biology, Department of Botany, Institute of Botany, University of InnsbruckInnsbruck, Austria
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Ganthaler A, Stöggl W, Mayr S, Kranner I, Schüler S, Wischnitzki E, Sehr EM, Fluch S, Trujillo-Moya C. Association genetics of phenolic needle compounds in Norway spruce with variable susceptibility to needle bladder rust. PLANT MOLECULAR BIOLOGY 2017; 94:229-251. [PMID: 28190131 PMCID: PMC5443855 DOI: 10.1007/s11103-017-0589-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 01/24/2017] [Indexed: 05/15/2023]
Abstract
KEY MESSAGE Accumulation of phenolic needle metabolites in Norway spruce is regulated by many genes with small and additive effects and is correlated with the susceptibility against fungal attack. Norway spruce accumulates high foliar concentrations of secondary phenolic metabolites, with important functions for pathogen defence responses. However, the molecular genetic basis underlying the quantitative variation of phenolic compounds and their role in enhanced resistance of spruce to infection by needle bladder rust are unknown. To address these questions, a set of 1035 genome-wide single nucleotide polymorphisms (SNPs) was associated to the quantitative variation of four simple phenylpropanoids, eight stilbenes, nine flavonoids, six related arithmetic parameters and the susceptibility to infection by Chrysomyxa rhododendri in an unstructured natural population of Norway spruce. Thirty-one significant genetic associations for the flavonoids gallocatechin, kaempferol 3-glucoside and quercetin 3-glucoside and the stilbenes resveratrol, piceatannol, astringin and isorhapontin were discovered, explaining 22-59% of phenotypic variation, and indicating a regulation of phenolic accumulation by many genes with small and additive effects. The phenolics profile differed between trees with high and low susceptibility to the fungus, underlining the importance of phenolic compounds in the defence mechanisms of Norway spruce to C. rhododendri. Results highlight the utility of association studies in non-model tree species and may enable marker-assisted selection of Norway spruce adapted to severe pathogen attack.
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Affiliation(s)
- Andrea Ganthaler
- Institute of Botany, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria.
- alpS - Centre for Climate Change Adaptation, Grabenweg 68, 6020, Innsbruck, Austria.
| | - Wolfgang Stöggl
- Institute of Botany, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria
| | - Stefan Mayr
- Institute of Botany, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria
| | - Ilse Kranner
- Institute of Botany, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria
| | - Silvio Schüler
- Department of Forest Genetics, Federal Research and Training Centre for Forests, Natural Hazards and Landscapes (BFW), Seckendorff-Gudent-Weg 8, 1131, Vienna, Austria
| | - Elisabeth Wischnitzki
- Health and Environment Department, AIT Austrian Institute of Technology GmbH, Konrad-Lorenz-Strasse 24, 3430, Tulln, Austria
| | - Eva Maria Sehr
- Health and Environment Department, AIT Austrian Institute of Technology GmbH, Konrad-Lorenz-Strasse 24, 3430, Tulln, Austria
| | - Silvia Fluch
- Health and Environment Department, AIT Austrian Institute of Technology GmbH, Konrad-Lorenz-Strasse 24, 3430, Tulln, Austria
| | - Carlos Trujillo-Moya
- Department of Forest Genetics, Federal Research and Training Centre for Forests, Natural Hazards and Landscapes (BFW), Seckendorff-Gudent-Weg 8, 1131, Vienna, Austria
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Beikircher B, Mayr S. Winter peridermal conductance of apple trees: lammas shoots and spring shoots compared. TREES (BERLIN, GERMANY : WEST) 2013; 27:707-715. [PMID: 23794789 PMCID: PMC3688303 DOI: 10.1007/s00468-012-0826-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 11/29/2012] [Accepted: 12/03/2012] [Indexed: 05/10/2023]
Abstract
Lammas shoots are flushes formed by some woody species later in the growing season. Having less time to develop, tissue formation is suggested to be incomplete leading to a higher peridermal water loss during consecutive months. In this study, we analysed morphological and anatomical parameters, peridermal conductance to water vapour and the level of native embolism in mid-winter and late-winter of lammas shoots and normal spring shoots of the apple varieties Malus domestica 'Gala' and 'Nicoter'. Lammas shoots showed a significantly higher shoot cross-sectional area due to larger pith and corticular parenchyma areas. In contrast, phloem was significantly thicker in spring shoots. No pronounced differences were observed in xylem and collenchyma thickness or mean hydraulic conduit diameter. The phellem of spring shoots was composed of more suberinised cells compared to lammas shoots, which led to a significantly higher peridermal conductance in the latter. The amount of native embolism in mid-winter did not differ between shoot types, but in late-winter lammas shoots were more embolised than spring shoots. Data show that the restricted vegetation period of lammas shoots affects their development and, in consequence, their transpiration shield. This may also pose a risk for winter desiccation.
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Affiliation(s)
- B. Beikircher
- Institute of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - S. Mayr
- Institute of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
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