Development of disease-resistant pennycress as a novel cover crop

Field pennycress a plant in the mustard family is emerging as a commercially viable winter covercrop for biofuel and edible oil production for the Midwestern agricultural rotation system becauseof its winter hardiness and high oil content.However pennycress is susceptible to fungal diseases.Under intensive cultivation fungal diseases will be more frequent and pose a major threat topennycress production. Durable disease resistance which overcomes the limits imposed byconventional breeding and replaces unsustainable chemical fungicides is urgently needed foradoption of pennycress as a commercially viable winter oilseed crop in the USA.During COVID-19 abbreviated Phase I funding CoverCress made significant progress towarddevelopment of two classes of plant defense peptides with entirely different modes of action forengineering broad-spectrum disease resistance in pennycress. Antifungal peptides with fungicidalactivity and small elicitor peptides capable of activating and amplifying pennycress' own defenseresponses were identified. Several chimeric genes for constitutive tissue-specific and pathogen- inducible expression of these peptides were constructed and introduced into pennycress throughAgrobacterium-mediated gene transfer. In Phase II research we will characterize transgenicpennycress lines for expression of the peptides and resistance to Alternaria leaf spot Rhizoctoniaroot and crown rot and Pythium damping-off. In addition we will identify pathogen-responsivepromoters for regulated expression of transgenes through transcriptome analysis of the pathogen- susceptible pennycress genotype identified in Phase I study.Our two-pronged strategy using two classes of plant defense peptides with different modes ofaction will pave the way for future commercial development of disease resistant pennycress.