title: Rapid generation of plant traits via regulation of DNA mismatch repair.
abstract: The reversible inhibition of DNA repair is a novel approach to maximize genetic diversity within a plant's genome in order to generate offspring exhibiting important de novo output traits. This process is based on the inhibition of the evolutionarily conserved mismatch repair (MMR) system. In this process, a human dominant negative MMR gene allele is introduced into the germline of a target plant, yielding progeny that can be screened to identify variants with commercially important agronomic output traits. Using this novel strategy, we generated MMR-deficient Arabidopsis thaliana plants that showed genome-wide instability of nucleotide repeats associated with chromosomal microsatellites, in addition to base substitution mutations. Functional screenings of the MMR-deficient Arabidopsis offspring identified variants expressing selectable traits (ethylene insensitivity and salt tolerance), as well as plants exhibiting altered morphologic traits (albinos and dwarfs). We determined by segregation analyses of variant plants that the de novo phenotypes were due to both recessive and dominant genetic mutations. Mutations caused by MMR deficiency showed a different spectrum compared with those derived using ethylmethane sulphonate (EMS) mutagenesis. Our finding demonstrates the feasibility of using reversible MMR deficiency via transient expression of a single human gene product to enhance genetic diversity in plants.
authors.affiliation: Morphotek Inc., 210 Welsh Pool Road, Exton, PA 19341, USA. chao@morphotek.com
authors.forename: Qimin
authors.initials: Q
authors.lastname: Chao
authors.forename: Christine D
authors.initials: CD
authors.lastname: Sullivan
authors.forename: John M
authors.initials: JM
authors.lastname: Getz
authors.forename: Kathryn B
authors.initials: KB
authors.lastname: Gleason
authors.forename: Philip M
authors.initials: PM
authors.lastname: Sass
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Nicolaides
authors.forename: Luigi
authors.initials: L
authors.lastname: Grasso