title: Transgenic Citrus Expressing an Arabidopsis NPR1 Gene Exhibit Enhanced Resistance against Huanglongbing (HLB; Citrus Greening).
abstract: Commercial sweet orange cultivars lack resistance to Huanglongbing (HLB), a serious phloem limited bacterial disease that is usually fatal. In order to develop sustained disease resistance to HLB, transgenic sweet orange cultivars 'Hamlin' and 'Valencia' expressing an Arabidopsis thaliana NPR1 gene under the control of a constitutive CaMV 35S promoter or a phloem specific Arabidopsis SUC2 (AtSUC2) promoter were produced. Overexpression of AtNPR1 resulted in trees with normal phenotypes that exhibited enhanced resistance to HLB. Phloem specific expression of NPR1 was equally effective for enhancing disease resistance. Transgenic trees exhibited reduced diseased severity and a few lines remained disease-free even after 36 months of planting in a high-disease pressure field site. Expression of the NPR1 gene induced expression of several native genes involved in the plant defense signaling pathways. The AtNPR1 gene being plant derived can serve as a component for the development of an all plant T-DNA derived consumer friendly GM tree.
authors.affiliation: Citrus Research and Education Center, University of Florida, Lake Alfred, Florida, United States of America.
authors.forename: Manjul
authors.initials: M
authors.lastname: Dutt
authors.affiliation: Citrus Research and Education Center, University of Florida, Lake Alfred, Florida, United States of America.
authors.forename: Gary
authors.initials: G
authors.lastname: Barthe
authors.affiliation: Southern Gardens Citrus, Clewiston, Florida, United States of America.
authors.forename: Michael
authors.initials: M
authors.lastname: Irey
authors.affiliation: Citrus Research and Education Center, University of Florida, Lake Alfred, Florida, United States of America.
authors.forename: Jude
authors.initials: J
authors.lastname: Grosser
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics*; D032084:Citrus sinensis / Q000235:genetics* / Q000382:microbiology; D060467:Disease Resistance / Q000235:genetics*; D018628:Gene Dosage; D015870:Gene Expression; D020022:Genetic Predisposition to Disease; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology*; D030821:Plants, Genetically Modified; D012230:Rhizobiaceae; D014170:Transformation, Genetic
chemical_list: D029681:Arabidopsis Proteins; C105496:NPR1 protein, Arabidopsis