The Disease Progression and Molecular Defense Response in Chenopodium Quinoa Infected with Peronospora Variabilis, the Causal Agent of Quinoa Downy Mildew.

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.

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.

The genome of Chenopodium pallidicaule: An emerging Andean super grain.

PREMISE: Cañahua is a semi-domesticated crop grown in high-altitude regions of the Andes. It is an A-genome diploid (2n = 2x = 18) relative of the allotetraploid (AABB) Chenopodium quinoa and shares many of its nutritional benefits. Cañahua seed contains a complete protein, a low glycemic index, and offers a wide variety of nutritionally important vitamins and minerals. METHODS: The reference assembly was developed using a combination of short- and long-read sequencing techniques, including multiple rounds of Hi-C-based proximity-guided assembly. RESULTS: The final assembly of the ~363-Mbp genome consists of 4633 scaffolds, with 96.6% of the assembly contained in nine scaffolds representing the nine haploid chromosomes of the species. Repetitive element analysis classified 52.3% of the assembly as repetitive, with the most common repeat identified as long terminal repeat retrotransposons. MAKER annotation of the final assembly yielded 22,832 putative gene models. DISCUSSION: 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.

Apoptins: selective anticancer agents.

Therapies that selectively target cancer cells for death have been the center of intense research recently. One potential therapy may involve apoptin proteins, which are able to induce apoptosis in cancer cells leaving normal cells unharmed. Apoptin was originally discovered in the Chicken anemia virus (CAV); however, human gyroviruses (HGyV) have recently been found that also harbor apoptin-like proteins. Although the cancer cell specific activity of these apoptins appears to be well conserved, the precise functions and mechanisms of action are yet to be fully elucidated. Strategies for both delivering apoptin to treat tumors and disseminating the protein inside the tumor body are now being developed, and have shown promise in preclinical animal studies.