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

Downy mildew disease, caused by the biotrophic oomycete , is the largest threat to the cultivation of quinoa ( Willd.) in the Andean highlands, and occurs worldwide. However, so far, no molecular study of the quinoa- interaction has been reported. Here, we developed tools to study downy mildew disease in quinoa at the gene expression level. 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 were analyzed by qRT-PCR, for quinoa homologues of 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 and the endochitinase showed no changes in gene expression. In contrast, quinoa orthologs of other defense response genes such as the transcription factor and the chaperone were significantly induced in plants infected with . These genes could be used as defense response markers to select quinoa cultivars that are more tolerant to infection.