title: Molecular tailoring of farnesylation for plant drought tolerance and yield protection.
abstract: Protecting crop yield under drought stress is a major challenge for modern agriculture. One biotechnological target for improving plant drought tolerance is the genetic manipulation of the stress response to the hormone abscisic acid (ABA). Previous genetic studies have implicated the involvement of the beta-subunit of Arabidopsis farnesyltransferase (ERA1) in the regulation of ABA sensing and drought tolerance. Here we show that molecular manipulation of protein farnesylation in Arabidopsis, through downregulation of either the alpha- or beta-subunit of farnesyltransferase enhances the plant's response to ABA and drought tolerance. To test the effectiveness of tailoring farnesylation in a crop plant, transgenic Brassica napus carrying an ERA1 antisense construct driven by a drought-inducible rd29A promoter was examined. In comparison with the non-transgenic control, transgenic canola showed enhanced ABA sensitivity, as well as significant reduction in stomatal conductance and water transpiration under drought stress conditions. The antisense downregulation of canola farnesyltransferase for drought tolerance is a conditional and reversible process, which depends on the amount of available water in the soil. Furthermore, transgenic plants were more resistant to water deficit-induced seed abortion during flowering. Results from three consecutive years of field trial studies suggest that with adequate water, transgenic canola plants produced the same amount of seed as the parental control. However, under moderate drought stress conditions at flowering, the seed yields of transgenic canola were significantly higher than the control. Using protein farnesyltransferase as an effective target, these results represent a successful demonstration of engineered drought tolerance and yield protection in a crop plant under laboratory and field conditions.
authors.affiliation: Performance Plants, Inc., Bioscience Complex, Queen's University, Kingston, ON, Canada K7L 3N6.
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.forename: Jifeng
authors.initials: J
authors.lastname: Ying
authors.forename: Monika
authors.initials: M
authors.lastname: Kuzma
authors.forename: Maryse
authors.initials: M
authors.lastname: Chalifoux
authors.forename: Angela
authors.initials: A
authors.lastname: Sample
authors.forename: Charlene
authors.initials: C
authors.lastname: McArthur
authors.forename: Tina
authors.initials: T
authors.lastname: Uchacz
authors.forename: Carlene
authors.initials: C
authors.lastname: Sarvas
authors.forename: Jiangxin
authors.initials: J
authors.lastname: Wan
authors.forename: David T
authors.initials: DT
authors.lastname: Dennis
authors.forename: Peter
authors.initials: P
authors.lastname: McCourt
authors.forename: Yafan
authors.initials: Y
authors.lastname: Huang
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000222:Adaptation, Physiological / Q000502:physiology*; D000704:Analysis of Variance; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029688:Brassica napus / Q000235:genetics / Q000378:metabolism; D004190:Disasters; D015536:Down-Regulation; D018526:Plant Transpiration; D030821:Plants, Genetically Modified; D017368:Protein Prenylation; D012639:Seeds / Q000254:growth & development / Q000378:metabolism
chemical_list: D000040:Abscisic Acid