Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Bacterial-induced calcium oscillations are common to nitrogen-fixing associations of nodulating legumes and non-legumes
Granqvist, E. ; Sun, J. ; Camp, R. Op den; Pujic, P. ; Hill, L. ; Normand, P. ; Morris, R.J. ; Downie, J.A. ; Geurts, R. ; Oldroyd, G.E.D. - \ 2015
New Phytologist 207 (2015). - ISSN 0028-646X - p. 551 - 558.
•Plants that form root-nodule symbioses are within a monophyletic ‘nitrogen-fixing’ clade and associated signalling processes are shared with the arbuscular mycorrhizal symbiosis. Central to symbiotic signalling are nuclear-associated oscillations in calcium ions (Ca2+), occurring in the root hairs of several legume species in response to the rhizobial Nod factor signal. •In this study we expanded the species analysed for activation of Ca2+ oscillations, including non-leguminous species within the nitrogen-fixing clade. •We showed that Ca2+ oscillations are a common feature of legumes in their association with rhizobia, while Cercis, a non-nodulating legume, does not show Ca2+ oscillations in response to Nod factors from Sinorhizobium fredii NGR234. Parasponia andersonii, a non-legume that can associate with rhizobia, showed Nod factor-induced calcium oscillations to S. fredii NGR234 Nod factors, but its non-nodulating sister species, Trema tomentosa, did not. Also within the nitrogen-fixing clade are actinorhizal species that associate with Frankia bacteria and we showed that Alnus glutinosa induces Ca2+ oscillations in root hairs in response to exudates from Frankia alni, but not to S. fredii NGR234 Nod factors. •We conclude that the ability to mount Ca2+ oscillations in response to symbiotic bacteria is a common feature of nodulating species within the nitrogen-fixing clade.
Competitive nodulation blocking of cv. Afghanistan pea is related to high levels of nodulation factors made by some strains of Rhizobium leguminosarum bv. viciae
Hogg, B. ; Davies, A.E. ; Wilson, K.E. ; Bisseling, T. ; Downie, J.A. - \ 2002
Molecular Plant-Microbe Interactions 15 (2002)1. - ISSN 0894-0282 - p. 60 - 68.
Cultivar Afghanistan peas are resistant to nodulation by many strains of Rhizobium leguminosarum bv. viciae but are nodulated by strain TOM, which carries the host specificity gene nodX. Some strains that lack nodX can inhibit nodulation of cv. Afghanistan by strain TOM. We present evidence that this “competitive nodulation-blocking” (Cnb) phenotype may result from high levels of Nod factors inhibiting nodulation of cv. Afghanistan peas. The TOM nod gene region (including nodX) is cloned on pIJ1095, and strains (including TOM itself) carrying pIJ1095 nodulate cv. Afghanistan peas very poorly but can nodulate other varieties normally. The presence of pIJ1095, which causes increased levels of Nod factor production, correlates with Cnb. Nodulation of cv. Afghanistan by TOM is also inhibited by a cloned nodD gene that increases nod gene expression and Nod factor production. Nodulation of cv. Afghanistan can be stimulated if nodD on pIJ1095 is mutated, thus severely reducing the level of Nod factor produced. Repression of nod gene expression by nolR eliminates the Cnb phenotype and can stimulate nodulation of cv. Afghanistan. Addition of Nod factors to cv. Afghanistan roots strongly inhibits nodulation. The Cnb(^ ) strains and added Nod factors inhibit infection thread initiation by strain TOM. The sym2(^A) allele determines resistance of cv. Afghanistan to nodulation by strains of R. leguminosarum bv. viciae lacking nodX. We tested whether sym2(^A) is involved in Cnb by using a pea line carrying the sym2(^A) region introgressed from cv. Afghanistan; nodulation in the introgressed line was inhibited by Cnb(^ ) strains. Therefore, the sym2(^A) region has an effect on Cnb, although another locus (or loci) may contribute to the stronger Cnb seen in cv. Afghanistan. Additional keywords: lipo-chitin-oligosaccharide, symbiosis.
D. Endo-B-mannanase activity during dormancy alleviation and germination of white spruce (Picea glauca) seeds.
Downie, C. ; Hilhorst, H.W.M. ; Bewley, J.D. - \ 1997
Physiologia Plantarum 101 (1997). - ISSN 0031-9317 - p. 405 - 415.
Sym2 of pea is involved in a nodulation factor-perception mechanism that controls the infection process in the epidermis.
Geurts, R. ; Heidstra, R. ; Hadri, A.E. ; Downie, J.A. ; Franssen, H. ; Kammen, A. van; Bisseling, T. - \ 1997
Plant Physiology 115 (1997). - ISSN 0032-0889 - p. 351 - 359.
In pea (Pisum sativum) up to 50 nodulation mutants are known, several of which are affected in the early steps of the symbiotic interaction with Rhizobium sp. bacteria. Here we describe the role of the sym2 gene in nodulation (Nod) factor perception. Our experiments show that the sym2A allele from the wild pea variety Afghanistan confers an arrest in infection-thread growth if the Rhizobium leguminosarum bv viciae strain does not produce Nod factors with a NodX-mediated acetylation at their reducing end. Since the induction of the early nodulin gene ENOD12 in the epidermis and the formation of a nodule primordium in the inner cortex were not affected, we conclude that more than one Nod factor-perception mechanism is active. Furthermore, we show that sym2A-mediated control of infection-thread growth was affected by the bacterial nodulation gene nodO.
Primary dormancy in tomato (Lycopersicon esculentum cv. Moneymaker)-studies with the sitiens mutant.
Hilhorst, H.W.M. ; Downie, B. - \ 1996
Journal of Experimental Botany 47 (1996). - ISSN 0022-0957 - p. 89 - 97.
Partial purification of endo-beta-mannanase and determination of its activity in polyacrylamide gels by using the Congo red method.
Toorop, P.E. ; Hilhorst, H.W.M. ; Kuijpers, I.J. ; Downie, B. - \ 1994
Acta botanica neerlandica 43 (1994). - ISSN 0044-5983 - p. 297 - 297.
Dormancy and germination of abscisic acid-deficient tomato seeds. Further studies with the sitiens mutant.
Hilhorst, H.W.M. ; Downie, B. - \ 1994
Plant Physiology 105 (1994). - ISSN 0032-0889 - p. 167 - 167.
A new assay for quantifying endo-beta-D-mannanase activity using Congo red dye.
Downie, B. ; Hilhorst, H.W.M. ; Bewley, J.D. - \ 1994
Phytochemistry 36 (1994). - ISSN 0031-9422 - p. 829 - 835.
Endo-beta-D-mannanase activity in mature, dry seeds of white spruce as detected by the Congo red assay.
Downie, B. ; Hilhorst, H.W.M. ; Bewley, J.D. - \ 1994
Acta botanica neerlandica 43 (1994). - ISSN 0044-5983 - p. 294 - 294.
Rhizobium nod genes are involved in inducing an early nodulin gene.
Govers, F. ; Moerman, M. ; Downie, J.A. ; Hooykaas, P. ; Franssen, H.G.J.M. ; Louwerse, J. ; Kammen, A. van; Bisseling, T. - \ 1986
Nature 323 (1986). - ISSN 0028-0836 - p. 564 - 566.
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