Postulation of virulence groups and resistance factors in the quinoa/downy mildew pathosystem using material from Ecuador

Ochoa, J.; Frinking, H. D.; Jacobs, Th.

doi:10.1046/j.1365-3059.1999.00352.x

Cited by 29 publications

(14 citation statements)

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“…Currently, very little is known about the physiological mechanisms involved in the P. variabilisquinoa interaction, or about the genetic basis of downy mildew tolerance and the role other phenotypic traits in disease susceptibility. Previous studies for quinoa tolerance using greenhouse experiments, seedlings, detached leaves and field scorings primarily focused on quantitative measures by scoring disease symptoms (Ochoa et al, 1999;Bonifacio, 2003;Khalifa and Thabet, 2018). Response to mildew infection utilizes visual scoring of disease severity, which is the proportion of leaf tissue with lesions caused by the pathogen .…”

Section: Introductionmentioning

confidence: 99%

Genetic variation for tolerance to the downy mildew pathogenPeronospora variabilisin genetic resources of quinoa (Chenopodium quinoa)

Colque-Little

Abondano

Lund

et al. 2020

Preprint

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Background: Quinoa (Chenopodium quinoa Willd.) is an ancient grain crop that is tolerant to abiotic stress and has favorable nutritional properties. Downy mildew is the main disease of quinoa and is caused by infections of the biotrophic oomycete Peronospora variabilis Gaüm. Since the disease causes major yield losses, identifying sources of downy mildew tolerance in genetic resources and understanding its genetic basis are important goals in quinoa breeding. Results: We infected 132 South American genotypes, three Danish cultivars and the weedy relative C. album with a single isolate of P. variabilis under greenhouse conditions and observed a large variation in disease traits like severity of infection, which ranged from 5% to 83%. Linear mixed models revealed a significant effect of genotypes on disease traits with high heritabilities (0.72 to 0.81). Factors like altitude at site of origin or seed saponin content did not correlate with mildew tolerance, but stomatal width was weakly correlated with severity of infection. Despite the strong genotypic effects on mildew tolerance, genome-wide association mapping with 88 genotypes failed to identify significant marker-trait associations indicating a polygenic architecture of mildew tolerance. Conclusions: The strong genetic effects on mildew tolerance allow to identify genetic resources, which are valuable sources of resistance in future quinoa breeding.

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Section: Introductionmentioning

confidence: 99%

Genetic variation for tolerance to the downy mildew pathogenPeronospora variabilisin genetic resources of quinoa (Chenopodium quinoa)

Colque-Little

Abondano

Lund

et al. 2020

Preprint

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“…Principal objectives for these programs include traditional breeding goals for grain yield, disease resistance (Ochoa et al 1999), drought tolerance, and saponin content, as well as the development of molecular markers to manage germplasm and facilitate traditional plant breeding.…”

Section: Introductionmentioning

confidence: 99%

A genetic linkage map of quinoa (Chenopodium quinoa) based on AFLP, RAPD, and SSR markers

et al. 2004

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Quinoa ( Chenopodium quinoa Willd.) is an important seed crop for human consumption in the Andean region of South America. It is the primary staple in areas too arid or saline for the major cereal crops. The objective of this project was to build the first genetic linkage map of quinoa. Selection of the mapping population was based on a preliminary genetic similarity analysis of four potential mapping parents. Breeding lines 'Ku-2' and '0654', a Chilean lowland type and a Peruvian Altiplano type, respectively, showed a low similarity coefficient of 0.31 and were selected to form an F(2) mapping population. The genetic map is based on 80 F(2) individuals from this population and consists of 230 amplified length polymorphism (AFLP), 19 simple-sequence repeat (SSR), and six randomly amplified polymorphic DNA markers. The map spans 1,020 cM and contains 35 linkage groups with an average marker density of 4.0 cM per marker. Clustering of AFLP markers was not observed. Additionally, we report the primer sequences and map locations for 19 SSR markers that will be valuable tools for future quinoa genome analysis. This map provides a key starting point for genetic dissection of agronomically important characteristics of quinoa, including seed saponin content, grain yield, maturity, and resistance to disease, frost, and drought. Current efforts are geared towards the generation of more than 200 mapped SSR markers and the development of several recombinant-inbred mapping populations.

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“…Most of the studies of P. variabilis have been oriented on screening quinoa cultivars for resistance in agricultural fields and observe quantitative differences in susceptibility [6-8, 16, 22, 23]. Some studies have evaluated the resistance of different quinoa cultivars to P. variabilis infection under controlled conditions [24,25] or detached leaf assays [12]. However, mechanistic understanding or molecular studies of the interaction of quinoa with P. variabilis or the downy mildew disease progression are not available.…”

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confidence: 99%

The disease progression and molecular defense response in Chenopodium quinoa infected with Peronospora variabilis, the causal agent of quinoa downy mildew

Palma-Encinas

Widell

et al. 2019

Preprint

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The downy mildew disease, caused by the biotrophic oomycete Peronospora variabilis, is the largest environmental threat to quinoa (Chenopodium quinoa Willd.) cultivation in the Andean highlands. However, so far no molecular information on the quinoa-Peronospora interaction has been reported. Here, we have developed tools to study the downy mildew disease in quinoa at gene expression level. Living P. variabilis could be isolated and maintained in the presence of a fungicide, allowing the characterization of downy mildew disease progression in two differently susceptible quinoa cultivars under controlled conditions. Quinoa gene expression changes induced by P. variabilis were analysed by qRT-PCR for quinoa homologues of Arabidopsis thaliana pathogen-associated genes. Overall, we observed a slower disease progression and higher tolerance in the quinoa cultivar Kurmi than in the cultivar Maniquena Real. We also observed that quinoa orthologs of A. thaliana genes involved in the salicylic acid defense response pathway (AtCAT2 and AtEP3) did not have changes in its gene expression. In contrast, quinoa orthologs of A. thaliana gene markers of the induction of the jasmonic acid response pathway (AtWRKY33 and AtHSP90) were significantly induced in plants infected with P. variabilis. These genes could be used as defense response markers to select quinoa cultivars that are more tolerant to P. variabilis infection.concentrations has further raised the interest in quinoa to meet future food demands internationally [1,[3][4][5]. However, quinoa production in the major original cultivation areas is strongly limited by the downy mildew disease, which can reduce the yield by 35-90% [6-9]. The downy mildew disease is caused by the oomycete P. variabilis Gäum. [4, 10, 11] and has been spread to every continent where quinoa is cultivated [12][13][14][15][16]. The worldwide distribution of P. variabilis has likely been expanded by commercial trade of infected seeds [17, 18]. P. variabilis specifically infects Chenopodium species and is an obligate biotroph [19,20]. Little is known about P. variabilis biology, including mode of transmission, leaf penetration and signals for sporangiospore and oospore formation [21]. Most of the studies of P. variabilis have been oriented on screening quinoa cultivars for resistance in agricultural fields and observe quantitative differences in susceptibility [6-8, 16, 22, 23]. Some studies have evaluated the resistance of different quinoa cultivars to P. variabilis infection under controlled conditions [24,25] or detached leaf assays [12]. However, mechanistic understanding or molecular studies of the interaction of quinoa with P. variabilis or the downy mildew disease progression are not available. With the recent availability of the genomic sequences of quinoa [26][27][28] and the close relatives to P. variabilis, Peronospora tabacina [29] and Hyaloperonospora arabidopsidis [30,31], improved methodology and knowledge on the infection cycle of P. variabilis can open up for detailed molecular studies...

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Postulation of virulence groups and resistance factors in the quinoa/downy mildew pathosystem using material from Ecuador

Cited by 29 publications

References 1 publication

Genetic variation for tolerance to the downy mildew pathogenPeronospora variabilisin genetic resources of quinoa (Chenopodium quinoa)

Genetic variation for tolerance to the downy mildew pathogenPeronospora variabilisin genetic resources of quinoa (Chenopodium quinoa)

A genetic linkage map of quinoa (Chenopodium quinoa) based on AFLP, RAPD, and SSR markers

The disease progression and molecular defense response in Chenopodium quinoa infected with Peronospora variabilis, the causal agent of quinoa downy mildew

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