Expression of pathogenesis-related proteins in transplastomic tobacco plants confers resistance to filamentous pathogens under field trials

BOCCARDO, NOELIA AYELEN; SEGRETIN, MARÍA EUGENIA; HERNANDEZ, INGRID; MIRKIN, FEDERICO GABRIEL; CHACÓN, OSMANI; LOPEZ, YUNIOR; BORRÁS-HIDALGO, ORLANDO; BRAVO-ALMONACID, FERNANDO FÉLIX

Scientific Reports

Nature

Lugar: Londres; Año: 2019 vol. 9

Plants are continuously challenged by pathogens, afecting most staple crops compromising foodsecurity. They have evolved diferent mechanisms to counterattack pathogen infection, including theaccumulation of pathogenesis-related (PR) proteins. These proteins have been implicated in activedefense, and their overexpression has led to enhanced resistance in nuclear transgenic plants, althoughin many cases constitutive expression resulted in lesion-mimic phenotypes. We decided to evaluateplastid transformation as an alternative to overcome limitations observed for nuclear transgenictechnologies. The advantages include the possibilities to express polycistronic RNAs, to obtainhigher protein expression levels, and the impeded gene fow due to the maternal inheritance of theplastome. We transformed Nicotiana tabacum plastids to co-express the tobacco PR proteins AP24 andβ-1,3-glucanase. Transplastomic tobacco lines were characterized and subsequently challenged withRhizoctonia solani, Peronospora hyoscyami f.sp. tabacina and Phytophthora nicotianae. Results showedthat transplastomic plants expressing AP24 and β-1,3-glucanase are resistant to R. solani in greenhouseconditions and, furthermore, they are protected against P.hyoscyami f.sp. tabacina and P. nicotianaein feld conditions under high inoculum pressure. Our results suggest that plastid co- expression of PRproteins AP24 and β-1,3-glucanase resulted in enhanced resistance against filamentous pathogens.