2011 Annual Report
As proposed, a transgenic test site has been prepared at the United States Department of Agriculture Picos Farm in Ft. Pierce, where Huanglongbing and Asian citrus psyllid are widespread. The first trees have been in place for more than fourteen months. The University of Florida has provided 300 transgenic citrus plants expressing genes expected to provide huanglongbing/canker resistance, which have been planted in the test site along with an additional 89 tress including preinoculated trees of sweet orange on a complex tetraploid rootstock that appeared to confer huanglongbing resistance in an earlier test. The United States Horticultural Research Laboratory has a permit approved from the Animal and Plant Health Inspection Service to conduct field trials of their transgenic plants at this site, with several hundred planted rootstocks transformed with the antimicrobial peptide D4E1. More than 120 citranges, from a well-characterized mapping population, and other trifoliate hybrids (plus sweet orange standards) have been propagated for a replicated trial, will be planted in July 2011, and monitored for Liberibacter development and huanglongbing symptoms. Data from this trial should provide information on markers and perhaps genes associated with huanglongbing resistance, for use in transgenic and conventional breeding.