Thirty-four cultivars of pea (Pisum sativum) were assayed for tumorigenesis after inoculation with Agrobacterium tumefaciens strain B6. The response of the 34 cultivars fell into 3 significantly different groups based on tumor weights: high, medium, and low susceptibility. The least susceptible cultivar, Sweet Snap, also formed the smallest tumors in comparison to 5 other cultivars when inoculated with 5 other strains of Agrobacterium. Preliminary experiments indicate that neither chemotaxis, binding, vir-gene induction, nor T-DNA expression are limiting factors in Sweet Snap's reduced susceptibility. In an inheritance study, the F1, F2, and F3 progeny from an initial cross between Sweet Snap and Wando (a more susceptible cultivar) formed tumors that were intermediate in weight between the two parents.

Cynipid gall formation is achieved by the intimate insect-plant interaction where by cynipid wasps redirect host plant development to form novel structures to protect and nourish the developing larva. To investigate the molecular mechanisms involved in this interaction, and extend our understanding of plant development, four approaches were taken. 1) A PCR based approach to search for genes to known signalling molecules: chitiooligosaccharides, or Nod factors, that control nodulation in the Rhizobia-legume interaction. PCR analysis was used to investigate the presence of the nodC gene in the cynipid gall wasp genome,h owever, no nodC-like sequencesw ere found. 2) SDS-PAGE analysis was carried out to compare inner-gall and non-gall protein signatures, demonstrating the variation between gall and non-gall tissue, and also that the protein signatures of inner-gall tissues vary between gall species. N-terminal sequencing and western blot analysis lead to the identification of a number of innergall proteins such as protein disulphide isomerase (PDI), formate dehydrogenase (FDH) and putative biotin carboxyl carrier protein (BCCP), involved in the synthesis of lipids in seeds. Analysis of the temporal and spatial expression of the putative BCCP revealed expression to be concentrated in the inner-gall cells throughout development, in all the gall species tested. 3) Cytological analysis of the inner-gall tissue was carried out throughout development of several gall species to investigate differences in their patterns of development and cytological characteristics of the inner-gall tissue, with many inner-gall cells being polytene. 4) A gall formation bioassay, to enable the activity of possible signals involved in gall formation to be tested, was developed. Rose callus tissue was used as a test tissue and the cynipid larval extract was exposed to this as a source of the active molecules. The induction of proteins in the callus after exposure to the larval extract was used as a molecular marker for activity. The polytene characteristic and the possible expression of seed proteins, suggest that seed developmental pathways may be used during gall formation.

No description available.

No description available.

No description available.

An investigation was conducted into gall induction in the leaves of Salix fragilis L. var. russelliana (Sm.) Koch by Pontania proxima (Lepeletier) (Hymenoptera: Tenthredinidae). The work was divided into four parts:- a) Reviews of the available literature were undertaken on: hypotheses concerning cecidogenesis of galls initiated by insects, the history of cecidology as it related to galls formed by insects, the ontogeny and morphology of galls produced by sawflies, ecological aspects of gall biology and the effects of galling on the host plant. b) Methods of rearing both insect and host were established; these resulted in an extension of the insect's flight period from five to eight months with three broods per year instead of the usual two. Further work established the topological specificity of oviposition. Preliminary studies were completed on the tissue culture of Salix leaf-disc explants and the fusion of protoplasts released from normal and galled tissue. c) Using light and electron microscopy, a study was made of the reproductive system and associated glands of Pontania proxima females, together with the first stages of the procecidium they initiated. Using these techniques, no microorganisms, viral or otherwise, were observed in the gall, in the lumina of the reproductive system and associated glands or in surrounding tissues of the insect. Evidence for a secretory role for the lateral oviducts was found. A structure termed the vaginal valve was described and it was hypothesized that this functioned to separate the fluids produced by the accessory glands from the contents of the oviduct, until oviposition. In the plant, it was observed that the gall effect was limited and that the presence of an egg or larva was not required for the formation of a procecidium. Gall growth was mainly due to periclinal divisions of the provascular tissues of the leaf. d) A bioassay, based on microinjection techniques, was developed .This demonstrated that the cecidogen was contained in the colleterial fluid produced by the accessory glands. Further analysis showed that the cecidogen had a molecular weight of less that 3 kDa.

Bibliography: leaves 125-140 / x, 140, [50] leaves, [3] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agricultural Biochemistry, 1984

Thesis (M.Sc.) - Carleton University, 2005. / Includes bibliographical references (p.58-63). Also available in electronic format on the Internet.

Thesis (M.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 151-170). Also available in electronic format on the Internet.

Diss.--Philosophische Fakultät I--Universität Zürich, 1989.