David F. Hildebrand

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In this work, the role of jasmonic acid (JA) in leaf senescence is examined. Exogenous application of JA caused premature senescence in attached and detached leaves in wild-type Arabidopsis but failed to induce precocious senescence of JA-insensitive mutant coi1 plants, suggesting that the JA-signaling pathway is required for JA to promote leaf senescence.(More)
We have built a series of vectors to allow the constitutive or light-regulated expression of foreign genes in plants. These vectors carry expression cassettes consisting of either the cauliflower mosaic virus 35S promoter or the pea rbcS-E9 promoter, a multiple cloning site derived from M13um20, and the rbcS-E9 polyadenylation site. These cassettes have(More)
In plants, changes in the levels of oleic acid (18:1), a major monounsaturated fatty acid (FA), results in the alteration of salicylic acid (SA)- and jasmonic acid (JA)-mediated defense responses. This is evident in the Arabidopsis ssi2/fab2 mutant, which encodes a defective stearoyl-acyl carrier protein-desaturase (S-ACP-DES) and consequently accumulates(More)
Vernolic acid (cis-12-epoxy-octadeca-cis-9-enoic acid) is valuable as a renewable chemical feedstock. This fatty acid can accumulate to high levels in the seed oil of some plant species such as Vernonia galamensis and Stokesia laevis which are unsuitable for large-scale production. A cost-effective alternative for production of epoxy fatty acids is to(More)
Triacylglycerol (TAG) is the main storage lipid in plants. Acyl-CoA: diacylglycerol acyltransferase (DGAT1 and DGAT2) and phospholipid: diacylglycerol acyltransferase (PDAT) can catalyze TAG synthesis. It is unclear how these three independent genes are regulated in developing seeds, and particularly if they have specific functions in the high accumulation(More)
Multiple forms of phospholipase D (PLD) were activated in response to wounding, and the expressions of PLDalpha, PLDbeta, and PLDgamma differed in wounded Arabidopsis leaves. Antisense abrogation of the common plant PLD, PLDalpha, decreased the wound induction of phosphatidic acid, jasmonic acid (JA), and a JA-regulated gene for vegetative storage protein.(More)
Three transformants of soybean, Glycine max (L.) Merr., have been recovered among a total of 18 plants regenerated by somatic embryogenesis from immature cotyledon tissues after cocultivation with Agrobacterium strains carrying a 15 kD zein gene (pH5PZ3D). DNA from upper leaves hybridized to a synthetic RNA probe specific for the zein sequence at a level(More)
Somatic embryos of soybean [Glycine max (L.) Merr.] are induced on immature cotyledons explanted onto a medium containing moderately high levels of auxin. Germinability of embryos is related to morphologic normality, and both are reduced by excessive exposure to auxin during the induction process. Shoot meristem development was improved by reducing exposure(More)
Induction of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR; EC 1.1.1.34) is essential for the synthesis of steroid derivatives and sesquiterpenoid phytoalexins in solanaceous plants following mechanical injury or pathogen infection. Gene-specific probes corresponding to different HMGR genes (hmg1 and hmg2) were used to study HMGR expression in(More)
Genotype has a large effect on the ability of immature soybean cotyledons to undergo auxin-stimulated somatic embryogenesis. Among 33 soybean lines, all those showing good regeneration were found to have in their pedigrees one or both of the highly regenerative ancestral lines, ‘Manchu’ or ‘A.K. Harrow’. When ‘Manchu’ was crossed with ‘Shiro’, a genotype(More)