Browsing by Autor "Allan G. Rasmusson"

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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.
Trichoderma harzianum T-22 and BOL-12QD inhibit lateral root development of Chenopodium quinoa in axenic co-culture
(Cogent OA, 2018) Oscar M. Rollano‐Peñaloza; Susanne Widell; Patricia Mollinedo; Allan G. Rasmusson
To investigate the symbiotic interaction of Trichoderma harzianum Rifai on Chenopodium quinoa Willd. in isolation, we studied axenic co-culture of the T. harzianum isolates T-22 and BOL-12QD and the C. quinoa cultivars Kurmi and Maniqueña real. Neither T-22 nor BOL-12QD affected seedling growth during two days of co-culture in the early growth phase of rapid primary root extension. However, after longer axenic co-culture, T-22 and BOL-12 were found to significantly inhibit the overall growth of C. quinoa cv. Kurmi and Real, affecting also vitality parameters as seen for chlorophyll and betalains. Lateral root development was strongly inhibited in all plant−fungal combinations, leaving stunted lateral roots. These results suggest that T. harzianum has a general capacity to inhibit the growth of C. quinoa plants with a main effect on the lateral root development.
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.
Transcriptomic analysis of quinoa reveals a group of germin-like proteins induced by Trichoderma
(2021) Oscar M. Rollano‐Peñaloza; Patricia Mollinedo; Susanne Widell; Allan G. Rasmusson
Abstract Symbiotic strains of fungi in the genus Trichoderma affect growth and pathogen resistance of many plant species, but the interaction is not known in molecular detail. Here we describe the transcriptomic response of two cultivars of the crop Chenopodium quinoa to axenic co-cultivation with Trichoderma harzianum BOL-12 and Trichoderma afroharzianum T22. The response of C. quinoa roots to BOL-12 and T22 in the early phases of interaction was studied by RNA sequencing and RT-qPCR verification. Interaction with the two fungal strains induced partially overlapping gene expression responses. Comparing the two plant genotypes, a broad spectrum of putative quinoa defense genes were found activated in the cultivar Kurmi but not in the Real cultivar. In cultivar Kurmi, relatively small effects were observed for classical pathogen response pathways but instead a C. quinoa -specific clade of germin-like genes were activated. Germin-like genes were found to be more rapidly induced in cultivar Kurmi as compared to Real. The same germin-like genes were found to also be upregulated systemically in the leaves. No strong correlation was observed between any of the known hormone-mediated defense response pathways and any of the quinoa- Trichoderma interactions. The differences in responses are relevant for the capabilities of applying Trichoderma agents for crop protection of different cultivars of C. quinoa .
Transcriptomic Analysis of Quinoa Reveals A Group of Germin-Like Proteins Induced By Trichoderma
(Research Square (United States), 2021) Oscar M. Rollano‐Peñaloza; Patricia Mollinedo; Susanne Widell; Allan G. Rasmusson
Abstract Background: Fungi in the Trichoderma genus affect growth and pathogen resistance of many plant species with different outcomes. Most plant- Trichoderma interactions result in a beneficial relationship. However, Trichoderma fungi may have a negative impact on certain plants depending on their genotype. Thus, plant- Trichoderma interactions outcome might depend on their genetic compatibility, which is not known in molecular detail. Results: Here we describe the transcriptomic response of two cultivars of Chenopodium quinoa to axenic co-cultivation with Trichoderma harzianum BOL-12 and Trichoderma afroharzianum T22. The response of C. quinoa roots to BOL-12 and T22 in the early phases of interaction was studied by RNA sequencing and RT-qPCR verification. Interaction with the two fungal strains induced partially overlapping gene expression responses. Comparing the two plant genotypes, a broad spectrum of putative quinoa defense genes were found activated in cultivar Kurmi but not in the Real cultivar. In cultivar Kurmi, relatively small effects were observed for classical pathogen response pathways but instead a C. quinoa -specific clade of putative defensive germin-like genes were activated. Germin-like genes were found to be more rapidly induced in cultivar Kurmi as compared to Real. The same germin-like genes were found to be upregulated systemically in Kurmi leaves. No strong correlation was observed between any of the known hormone-mediated defense response pathways and any of the quinoa- Trichoderma interactions. Conclusions: C. quinoa triggers a set of germin-like defensive genes in response to Trichoderma interaction. Quinoa germin-like gene expression is cultivar-specific upon interaction with Trichoderma and was found to be expressed also systemically. The observed differences of quinoa response to Trichoderma for each quinoa cultivar are relevant for the application of Trichoderma agents for quinoa crop protection.
Transcriptomic Analysis of Quinoa Reveals a Group of Germin-Like Proteins Induced by Trichoderma
(Frontiers Media, 2021) Oscar M. Rollano‐Peñaloza; Patricia Mollinedo; Susanne Widell; Allan G. Rasmusson
Symbiotic strains of fungi in the genus Trichoderma affect growth and pathogen resistance of many plant species, but the interaction is not known in molecular detail. Here we describe the transcriptomic response of two cultivars of the crop Chenopodium quinoa to axenic co-cultivation with Trichoderma harzianum BOL-12 and Trichoderma afroharzianum T22. The response of C. quinoa roots to BOL-12 and T22 in the early phases of interaction was studied by RNA sequencing and RT-qPCR verification. Interaction with the two fungal strains induced partially overlapping gene expression responses. Comparing the two plant genotypes, a broad spectrum of putative quinoa defense genes were found activated in the cultivar Kurmi but not in the Real cultivar. In cultivar Kurmi, relatively small effects were observed for classical pathogen response pathways but instead a C. quinoa-specific clade of germin-like genes were activated. Germin-like genes were found to be more rapidly induced in cultivar Kurmi as compared to Real. The same germin-like genes were found to also be upregulated systemically in the leaves. No strong correlation was observed between any of the known hormone-mediated defense response pathways and any of the quinoa-Trichoderma interactions. The differences in responses are relevant for the capabilities of applying Trichoderma agents for crop protection of different cultivars of C. quinoa.
Transcriptomic Profiling of Quinoa Reveals Distinct Defense Responses to Exogenous Methyl Jasmonate and Salicylic Acid
(Multidisciplinary Digital Publishing Institute, 2025) Oscar M. Rollano‐Peñaloza; Sara Neyrot; Jose Antonio Bravo Barrera; Patricia Mollinedo Portugal; Allan G. Rasmusson
Plant defense responses are mediated by hormones such as jasmonic acid (JA) and salicylic acid (SA). JA and SA are known to trigger a range of different defense responses in model plants but little is described in crops like quinoa. Here, we present the first molecular description of JA and SA signaling at the transcriptomic level in quinoa. The transcriptomes of quinoa cv. Kurmi seedlings treated with 100 µM methyl JA or 1 mM SA for 4 h were analyzed, using on average 4.1 million paired-end reads per sample. Quinoa plants treated with JA showed 1246 differentially expressed (DE) genes and plants treated with SA showed 590 DE genes. The response to JA included the induction of genes for the biosynthesis of JA (8/8 genes) and lignin (10/11 genes), and displayed a strong association with treatments with Trichoderma biocontrol agents. The SA treatment triggered the upregulation of genes for the biosynthesis of monoterpenoids and glucosinolates, both having defense properties. Overall, this suggest that JA and SA promotes the biosynthesis of lignin polymers and chemical defense compounds, respectively. Overall, the DE genes identified can be used as molecular markers in quinoa for tracking plant-hormone pathway involvements in defense responses.