Transgenic American chestnuts show enhanced blight resistance and transmit the trait to T1 progeny.
Andrew E. Newhouse,Linda D. Polin-Guigan,Kathleen A. Baier,Kristia E.R. Valletta,William H. Rottmann,Timothy J. Tschaplinski,Charles A. Maynard,William A. Powell
2014 April 13 Plant Science, DOI: 10.1016/j.plantsci.2014.04.004
American chestnut (Castanea dentata)
is a classic example of a native keystone species that was nearly
eradicated by an introduced fungal pathogen. This report describes
progress made toward producing a fully American chestnut tree with
enhanced resistance to the blight fungus (Cryphonectria parasitica). The transgenic American chestnut ‘Darling4,’ produced through an Agrobacterium
co-transformation procedure to express a wheat oxalate oxidase gene
driven by the VspB vascular promoter, shows enhanced blight resistance
at a level intermediate between susceptible American chestnut and
resistant Chinese chestnut (Castanea mollissima). Enhanced
resistance was identified first with a leaf-inoculation assay using
young chestnuts grown indoors, and confirmed with traditional stem
inoculations on 3- and 4-year-old field-grown trees. Pollen from
‘Darling4′ and other events was used to produce transgenic T1 seedlings,
which also expressed the enhanced resistance trait in leaf assays.
Outcrossed transgenic seedlings have several advantages over
tissue-cultured plantlets, including increased genetic diversity and
faster initial growth. This represents a major step toward the
restoration of the majestic American chestnut.
•Two putative resistance-enhancing genes have been integrated into American chestnut. •Transgenic American chestnut trees show significantly enhanced resistance to chestnut blight. •Transgenes can be transmitted to a T1 generation that shows similarly enhanced blight resistance. •Co-transformation is an effective method of separately introducing multiple genes into a tree host.
Andrew E. Newhouse, Linda D. Polin-McGuigan, Kathleen A. Baier, Kristia E.R. Valletta, William H. Rottmann, Timothy J. Tschaplinski, Charles A. Maynard, William A. Powell, Transgenic American chestnuts show enhanced blight resistance and transmit the trait to T1 progeny, Plant Science, Available online 13 April 2014, ISSN 0168-9452