Shen, Z., Corbin, D. R., Greenplate, J. T., Grebenok, R. J., Galbraith, D. W., & Purcell, J. P. (1997). Studies on the mode of action of cholesterol oxidase on insect midgut membranes. Archives of Insect Biochemistry and Physiology, 34(4), 429-442.
Abstract:
Cholesterol oxidase (EC 1.1.3.6.) is an insecticidal protein known to have potent activity against the boll weevil, milder activity against a number of lepidopteran species, and virtually no activity against other insects. Several factors that could explain its species-dependent differential activity were examined. We compared cholesterol concentrations and rates of cholesterol oxidation in the midgut membranes from larvae of boll weevil (Anthonomus grandis grandis Boheman), southern corn rootworm (Diabrotica undecimpunctata Howardi Barber), tobacco budworm (Heliothis virescens Fabricius), and yellow mealworm (Tenebrio molitor Linnaeus). Results showed that cholesterol concentration alone could not account for the differences in insecticidal activity and that midgut brush-border membranes of all species tested were generally susceptible to oxidation by cholesterol oxidase in vitro. We also demonstrated that cholesterol oxidase stability in the midgut environment was similar for the species tested and thus could not account for the differential activity. However, comparison of the pH of the insect midgut fluids with the pH optimum of cholesterol oxidase indicated that the lower sensitivity of lepidopteran larvae to the enzyme may be partially due to the alkaline nature of their midgut environments. In some species, oxidation caused significant changes in the activities of brush-border membrane alkaline phosphatase, and these changes did correlate with the susceptibility of the insect to cholesterol oxidase. © 1997 Wiley-Liss, Inc.
Liu, Y., Zhang, G., Bernardo, M., Leung, H., Zhu, X. Y., Zhang, S., Liu, B., Edwards, J., Galbraith, D. W., & Leach, J. (2011). Dissecting quantitative resistance against blast disease using heterogeneous inbred family lines in rice. Theoretical and Applied Genetics, 122(2), 341-353.
PMID: 20872132;Abstract:
SHZ-2 is an indica rice cultivar that exhibits broad-spectrum resistance to rice blast; it is widely used as a resistance donor in breeding programs. To dissect the QTL responsible for broad-spectrum blast resistance, we crossed SHZ-2 to TXZ-13, a blast susceptible indica variety, to produce 244 BC4F3 lines. These lines were evaluated for blast resistance in greenhouse and Weld conditions. Chromosomal introgressions from SHZ-2 into the TXZ-13 genome were identiWed using a single feature polymorphism microarray, SSR markers and gene-speciWc primers. Segregation analysis of the BC4F3 population indicated that three regions on chromosomes 2, 6, and 9, designated as qBR2.1, qBR6.1, and qBR9.1, respectively, was associated with blast resistance and contributed 16.2, 14.9, and 22.3%, respectively, to the phenotypic variance of diseased leaf area (DLA). We further narrowed the three QTL regions using pairs of sister lines extracted from heterogeneous inbred families (HIF). Pairwise comparison of these lines enabled the determination of the relative contributions of individual QTL. The qBR9.1 conferred strong resistance, whereas qBR2.1 or qBR6.1 individually did not reduce disease under Weld conditions. However, when qBR2.1 and qBR6.1 were combined, they reduced disease by 19.5%, suggesting that small eVect QTLs contribute to reduction of epidemics. The qBR6.1 and qBR9.1 regions contain nucleotide-binding sites and leucine rich repeats (NBS-LRR) sequences, whereas the qBR2.1 did not. In the qBR6.1 region, the patterns of expression of adjacent NBS-LRR genes were consistent in backcross generations and correlated with blast resistance, supporting the hypothesis that multiple resistance genes within a QTL region can contribute to non-race-speciWc quantitative resistance. © Springer-Verlag 2010.
Ophir, R., Pang, X., Halaly, T., Venkateswari, J., Lavee, S., Galbraith, D., & Etti, O. r. (2009). Gene-expression profiling of grape bud response to two alternative dormancy-release stimuli expose possible links between impaired mitochondrial activity, hypoxia, ethylene-ABA interplay and cell enlargement. Plant Molecular Biology, 71(4-5), 403-423.
PMID: 19653104;Abstract:
A grape-bud-oriented genomic platform was produced for a large-scale comparative analysis of bud responses to two stimuli of grape-bud dormancy release, hydrogen cyanamide (HC) and heat shock (HS). The results suggested considerable similarity in bud response to the stimuli, both in the repertoire of responding genes and in the temporary nature of the transcriptome reprogramming. Nevertheless, the bud response to HC was delayed, more condensed and stronger, as reflected by a higher number of regulated genes and a higher intensity of regulation compared to the response to HS. Integrating the changes occurring in response to both stimuli suggested perturbation of mitochondrial activity, development of oxidative stress and establishment of a situation that resembles hypoxia, which coincides with induction of glycolysis and fermentation, as well as changes in the interplay between ABA and ethylene metabolism. The latter is known to induce various growth responses in submerged plants and the possibility of a similar mechanism operating in the bud meristem during dormancy release is raised. The new link suggested between sub lethal stress, mitochondrial activity, hypoxic conditions, ethylene metabolism and cell enlargement during bud dormancy release may be instrumental in understanding the dormancy-release mechanism. Temporary increase of acetaldehyde, ethanol and ethylene in response to dormancy release stimuli demonstrated the predictive power of the working model, and its relevance to dormancy release was demonstrated by enhancement of bud break by exogenous ethylene and its inhibition by an ethylene signal inhibitor. © 2009 Springer Science+Business Media B.V.
Galbraith, D. W., Bhosale, R., Boudolf, V., Cuevasa, F., Kumpf, R., Hu, Z., Van Isterdael, G., Lambert, G., Nowack, M., Smith, R., Vercauteren, I., De Rycke, R., Storme, V., Beeckman, T., Larkin, J., Kremer, A., Höfte, H., Kumpf, R., Maere, S., & De Veylder, L. (2017). A spatiotemporal DNA endoploidy map of the Arabidopsis root reveals roles for the endocycle in root development and stress adaptation.. Plant Cell.
Winkler, R. G., Frank, M. R., Galbraith, D. W., Feyereisen, R., & Feldmann, K. A. (1998). Systematic reverse genetics of transfer-DNA-tagged lines of Arabidopsis - Isolation of mutations in the cytochrome P450 gene superfamily. PLANT PHYSIOLOGY, 118(3), 743-749.
