Browsing by Autor "Valeria Palma-Encinas"

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First report of Peronospora variabilis causing downy mildew disease in cañahua (Chenopodium pallidicaule) in Bolivia
(2021) Oscar M. Rollano‐Peñaloza; Valeria Palma-Encinas; Paola M. Nogales-Ascarrunz; Susanne Widell; Allan G. Rasmusson; Patricia Mollinedo
<title>Abstract</title> Cañahua (<italic>Chenopodium pallidicaule</italic> Aellen) is a semi-domesticated grain cultivated in the Andean highlands for millennia. Cañahua seeds have high nutritional value and it has become attractive because of its high resistance to frost, drought and saline soils. In May 2018, cañahua plants showed symptoms of the downy mildew disease caused by <italic>Peronospora variabilis</italic> which is known to heavily affect its tetraploid-relative quinoa. Besides the typical symptoms in the plant, visual confirmation of <italic>P. variabilis</italic> reproductive structures by microscopy was achieved. In order to verify the ability of <italic>P. variabilis</italic> to infect cañahua, an artificial infection in three cañahua varieties was performed. The three cañahua varieties were infected by <italic>P. variabilis</italic> and developed downy mildew disease symptoms. The pathogen identity was confirmed by PCR and Sanger sequencing of the <italic>PvCox2</italic> and <italic>PvITS region</italic>. DNA sequence identification confirmed that the <italic>P. variabilis</italic> that usually infects quinoa can also infect cañahua plants. Therefore, cañahua when grown next to quinoa must be carefully watched for downy mildew disease symptoms because <italic>P. variabilis</italic> can be a potential threat for future large scale cañahua agriculture.
The disease progression and molecular defense response in Chenopodium quinoa infected with Peronospora variabilis , the causal agent of quinoa downy mildew
(2019) Oscar M. Rollano‐Peñaloza; Valeria Palma-Encinas; Susanne Widell; Allan G. Rasmusson; Patricia Mollinedo
Abstract 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.
The Disease Progression and Molecular Defense Response in Chenopodium Quinoa Infected with Peronospora Variabilis, the Causal Agent of Quinoa Downy Mildew
(Multidisciplinary Digital Publishing Institute, 2022) Oscar M. Rollano‐Peñaloza; Valeria Palma-Encinas; Susanne Widell; Patricia Mollinedo; Allan G. Rasmusson
Downy mildew disease, caused by the biotrophic oomycete Peronospora variabilis, is the largest threat to the cultivation of quinoa (Chenopodium quinoa Willd.) in the Andean highlands, and occurs worldwide. However, so far, no molecular study of the quinoa-Peronospora interaction has been reported. Here, we developed tools to study downy mildew disease in quinoa at the gene expression level. P. variabilis was isolated and maintained, allowing the study of downy mildew disease progression in two quinoa cultivars under controlled conditions. Quinoa gene expression changes induced by P. variabilis were analyzed by qRT-PCR, for quinoa homologues of A. thaliana pathogen-associated genes. Overall, we observed a slower disease progression and higher tolerance in the quinoa cultivar Kurmi than in the cultivar Maniqueña Real. The quinoa orthologs of putative defense genes such as the catalase CqCAT2 and the endochitinase CqEP3 showed no changes in gene expression. In contrast, quinoa orthologs of other defense response genes such as the transcription factor CqWRKY33 and the chaperone CqHSP90 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.
The genome of Chenopodium pallidicaule: An emerging Andean super grain
(Botanical Society of America, 2019) Hayley Mangelson; David E. Jarvis; Patricia Mollinedo; Oscar M. Rollano‐Peñaloza; Valeria Palma-Encinas; Luz Gómez-Pando; Eric N. Jellen; Peter J. Maughan
When compared with quinoa, strong patterns of synteny support the hypothesis that cañahua is a close A-genome diploid relative, and thus potentially a simplified model diploid species for genetic analysis and improvement of quinoa. Resequencing and phylogenetic analysis of a diversity panel of cañahua accessions suggests that coordinated efforts are needed to enhance genetic diversity conservation within ex situ germplasm collections.