Judith K Brown

Judith K Brown

Professor, Plant Science
Regents Professor, Plant Sciences
Research Associate Professor, Entomology
Professor, Entomology / Insect Science - GIDP
Professor, BIO5 Institute
Member of the General Faculty
Member of the Graduate Faculty
Primary Department
Department Affiliations
Contact
(520) 621-1402

Work Summary

Unravel the phylodynamics and transmission-specific determinants of emerging plant virus/fastidious bacteria-insect vector complexes, and translate new knowledge to abate pathogen spread in food systems.

Research Interest

Judith Brown, PhD, and her research interests include the molecular epidemiology of whitefly-transmitted geminiviruses (Begomoviruses, Family: Geminiviridae), the basis for virus-vector specificity and the transmission pathway, and the biotic and genetic variation between populations of the whitefly vector, B. tabaci, that influence the molecular epidemiology and evolution of begomoviruses. Keywords: Plant viral genomics, emergent virus phylodynamics, functional genomics of insect-pathogen interactions

Publications

Hernández-Zepeda, C., Idris, A. M., Carnevali, G., Brown, J. K., & Moreno-Valenzuela, O. (2007). Molecular characterization and experimental host range of Euphorbia mosaic virus-Yucatan Peninsula, a begomovirus species in the Squash leaf curl virus clade. Plant Pathology, 56(5), 763-770.

Abstract:

Euphorbia mosaic virus (EuMV), a tentative species within the genus Begomovirus, was isolated from Euphorbia heterophylla plants growing in the Yucatan Peninsula, Mexico. The complete bipartite genome was cloned from total DNA extracts and the nucleotide (nt) sequence was determined. The DNA-A sequence of the EuMV-Yucatan Peninsula (EuMV-YP) isolate shared 95% nt identity with the partially characterized type EuMV isolate from Puerto Rico. The EuMV-YP genome organization was like that of other New World, bipartite begomoviruses. The DNA-A component was 2613 nt in size, while the DNA-B component was 2602 nt long. The 165-nt common region (CR) sequence for the DNA-A and DNA-B components shared a lower than expected nt identity of 86%. The organization and iterons of the putative AC1 binding site of EuMV-YP were similar to those of begomoviruses in the Squash leaf curl virus (SLCV) clade. Characteristic disease symptoms were reproduced in E. heterophylla plants inoculated at the seedling stage using the cloned viral DNA-A and DNA-B components, confirming disease aetiology. Results of an experimental host-range study for EuMV-YP indicated that it infected at least five species in three plant families, including the Euphorbiaceae (E. heterophylla), Solanaceae (Datura stramonium, pepper, tomato) and Fabaceae (bean). Phylogenetic analysis of the DNA-A and DNA-B components indicated that EuMV-YP is a New World begomovirus and that it is a new member of the SLCV clade. © 2007 The Authors.

Brown, J. K. (2015). First report of begomoviruses infecting tomato with leaf curl disease in Burkina Faso (Short report). Plant Dis., 99:, 732.

Sattar, M.N., Koutou, M., Hosseini, S., Leke, W., Brown, J.K., and Kvarnheden, A. 2015. First report of begomoviruses infecting tomato with leaf curl disease in Burkina Faso. Plant Dis. 99: 732.

Bedford, I. D., Briddon, R. W., Brown, J. K., Rosell, R. C., & Markham, P. G. (1994). Geminivirus-transmission and biological characterisation of Bermisia tabaci (Gennadius) biotypes from different geographic regions. Annals of Applied Biology, 125(2), 311-326.
Muhire, B., Martin, D. P., Brown, J. K., Navas-Castillo, J., Moriones, E., Zerbini, F., Rivera-Bustamante, R., Malathi, V. G., Briddon, R. W., & Varsani, A. (2013). A genome-wide pairwise-identity-based proposal for the classification of viruses in the genus Mastrevirus (family Geminiviridae). Archives of Virology, 158(6), 1411-1424.

PMID: 23340592;Abstract:

Recent advances in the ease with which the genomes of small circular single-stranded DNA viruses can be amplified, cloned, and sequenced have greatly accelerated the rate at which full genome sequences of mastreviruses (family Geminiviridae, genus Mastrevirus) are being deposited in public sequence databases. Although guidelines currently exist for species-level classification of newly determined, complete mastrevirus genome sequences, these are difficult to apply to large sequence datasets and are permissive enough that, effectively, a high degree of leeway exists for the proposal of new species and strains. The lack of a standardised and rigorous method for testing whether a new genome sequence deserves such a classification is resulting in increasing numbers of questionable mastrevirus species proposals. Importantly, the recommended sequence alignment and pairwise identity calculation protocols of the current guidelines could easily be modified to make the classification of newly determined mastrevirus genome sequences significantly more objective. Here, we propose modified versions of these protocols that should substantially minimise the degree of classification inconsistency that is permissible under the current system. To facilitate the objective application of these guidelines for mastrevirus species demarcation, we additionally present a user-friendly computer program, SDT (species demarcation tool), for calculating and graphically displaying pairwise genome identity scores. We apply SDT to the 939 full genome sequences of mastreviruses that were publically available in May 2012, and based on the distribution of pairwise identity scores yielded by our protocol, we propose mastrevirus species and strain demarcation thresholds of >78 % and >94 % identity, respectively. © 2013 Springer-Verlag Wien.

Brown, J. K. (2013). Spatio-temporal patterns of genetic change amongst cassava Bemisia tabaci whiteflies driving virus pandemics in East and Central Africa.. Virus Research, 158, doi.org/10.1016/j.virusres.2013.11.018..

Legg, J.P., P. Sseruwagi, S, Boniface, G. Okao-Okuja, R. Shirima, S. Bigirimana, Gervais Gashaka, H.-W. Herrmann, S. Jeremiah, H. Obiero, I. Ndyetabula, W. Tata-Hangy, C. Masembe, and J. K. Brown. 2013. Spatio-temporal patterns of genetic change amongst cassava Bemisia tabaci whiteflies driving virus pandemics in East and Central Africa. Virus Res. doi.org/10.1016/j.virusres.2013.11.018.