Figure 1. Nicotiana attenuata plants were transformed to ectopically express an antimicrobial peptide (AMP) and planted into a research field plot in the plants´ native environment.
(A) Overview scheme of the experimental approach. AMP expression was used to target bacteria in planta as an ecological tool to unravel microbiome function under field conditions regarding contribution to plant performance, fitness and defense against herbivores. (B) Location of the experimental field plot at the Lytle Ranch Preserve in Utah (USA), which was used for the field releases in 2011, 2012 and 2013. Figure composed with maps provided by d-maps.com (http://d-maps.com/m/america/usa/utah/utah/utah09.pdf; http://d-maps.com/m/america/usa/arizona/arizona/arizona13.pdf; http://d-maps.com/m/america/usa/nevada/nevada/nevada09.pdf). (C) Larger view of the plants planted at the field plot.
Figure 1—figure supplement 1. Antimicrobial peptide (AMP) selection scheme for the identification of eligible candidates for host-microbe manipulation studies in the field.
Wild tobacco plants (N. attenuata) were transformed for the ectopic expression of various different AMPs (Gase et al., 2011). Ten antimicrobial peptides showed reliable gene expression levels within the transgenic plants over multiple generations (Weinhold et al., 2013). Among these, three peptides showed particularly high accumulation levels within the leaf apoplast (Weinhold et al., 2015). Finally, plants transformed with Mc-AMP1 from the common ice plant demonstrated in planta activity against bacteria (this study).