Judith K Brown
Professor, BIO5 Institute
Professor, Plant Science
Research Associate Professor, Entomology
Professor, Entomology / Insect Science - GIDP
Primary Department
Department Affiliations
(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

Leke, W. N., Fondong, V. N., & Khatabi, B. (2016). Illumina sequencing of the first begomovirus infecting fluted pumpkin (Telfairia occidentalis) plants in Cameroon (Annotated sequence record).. Arch. Virol., doi 10.1007/s00705-016-2915-7.

Leke, W.N., Khatabi, B., Fondong, V.N., and Brown, J.K. 2016. Illumina sequencing of the first begomovirus infecting fluted pumpkin (Telfairia occidentalis) plants in Cameroon: Annotated sequence record. Arch.Virol doi 10.1007/s00705-016-2915-7.

Nunes, E. S., Brown, J. K., Moreira, A. G., Watson, G., Lourenção, A. L., Piedade, S. M., A., J., & Vieira, M. L. (2008). First report and differential colonization of Passiflora species by the B biotype of Bemisia tabaci (Gennadius) (hemiptera: Aleyrodidae) in Brazil. Neotropical Entomology, 37(6), 744-746.

PMID: 19169568;Abstract:

This note is the first report of Bemisia tabaci (Gennadius) biotype B colonizing passionvine in Brazil. We examined the colonization of nine Passiflora species by a wild B type population under greenhouse conditions. P. amethystina Mikan was the most preferred species for oviposition and colonization, whereas P. suberosa L., P. coriacea Juss. and two commercially cultivated species, P. alata Curtis and P. edulis Sims f.flavicarpa Degener, were mostly uncolonised. P. morifolia Mast., P. cincinnata Mast., P. foetida L. and P. caerulea L. showed intermediate levels of colonization. Such differential colonization might suggest some degree of resistance by certain Passiflora species or oviposition preference by B. tabaci.

Fauquet, C. M., Sawyer, S., Idris, A. M., & Brown, J. K. (2005). Sequence analysis and classification of apparent recombinant begomoviruses infecting tomato in the Nile and Mediterranean Basins. Phytopathology, 95(5), 549-555.

PMID: 18943321;Abstract:

Numerous whitefly-transmitted viral diseases of tomato have emerged in countries around the Nile and Mediterranean Basins the last 20 years. These diseases are caused by monopartite geminiviruses (family Geminiviridae) belonging to the genus Begomovirus that probably resulted from numerous recombination events. The molecular biodiversity of these viruses was investigated to better appreciate the role and importance of recombination and to better clarify the phylogenetic relationships and classification of these viruses. The analysis partitioned the tomato-infecting begomoviruses from this region into two major clades, Tomato yellow leaf curl virus and Tomato yellow leaf curl Sardinia virus. Phylogenetic and pairwise analyses together with an evaluation for gene conversion were performed from which taxonomic classification and virus biodiversity conclusions were drawn. Six recombination hotspots and three homogeneous zones within the genome were identified among the tomato-infecting isolates and species examined here, suggesting that the recombination events identified were not random occurrences. © 2005 The American Phytopathological Society.

Papayiannis, L. C., Iacovides, T. A., Katis, N. I., & Brown, J. K. (2010). Differentiation of Tomato yellow leaf curl virus and Tomato yellow leaf curl Sardinia virus using real-time TaqMan® PCR. Journal of Virological Methods, 165(2), 238-245.

PMID: 20153376;Abstract:

During the past four decades, Tomato yellow leaf curl disease has become one of the major constraints in tomato production worldwide. In the Mediterranean basin, several isolates from two major Begomovirus species are involved in outbreaks and persistent epidemics. A real-time TaqMan® PCR assay was developed and evaluated for the rapid and multiplex detection and differentiation of two begomoviruses often found in mixed infections in the region, Tomato yellow leaf curl virus (TYLCV) and Tomato yellow leaf curl Sardinia virus (TYLCSV). This assay was 1000-fold more sensitive than conventional PCR assays described previously, allowing the use of simple template preparation methods and eliminating the need for total nucleic acid purification. The viral DNA template was obtained by spotting sap extract derived from TYLCV or TYLCSV infected tissues on a nylon membrane or by directly using crude plant extracts in the real-time reaction cocktail. Preliminary results showed that this method can successfully detect and discriminate virus species from infected tomato, bean, pepper and different weed species obtained from the Mediterranean basin, the USA and Japan, allowing the simple, fast and cost-effective testing of a large number of samples in certification schemes. The assay can also be used for the detection of these two begomovirus species in their whitefly vector biotypes of the Bemisia tabaci (Gennadius) species group. © 2010 Elsevier B.V.

Paximadis, M., Idris, A. M., Torres-Jerez, I., Villarreal, A., Rey, M. E., & Brown, J. K. (1999). Characterization of tobacco geminiviruses in the old and new world. Archives of Virology, 144(4), 703-717.

PMID: 10365162;Abstract:

Biological differences and molecular variability between six phenotypically distinct tobacco-infecting geminivirus isolates from southern Africa (Zimbabwe) and Mexico were investigated. Host range studies conducted with tobacco virus isolates ZIM H from Zimbabwe and MEX 15 and MEX 32 from Mexico indicated all had narrow host ranges restricted to the Solanaceae. Alignment of coat protein gene (CP) and common region (CR) sequences obtained by PCR, and phylogenetic analysis of the CP sequences indicated Zimbabwean isolates were distantly related to those from Mexico and that geographically proximal isolates shared their closest affinities with Old and New World geminiviruses, respectively. Zimbabwean isolates formed a distinct cluster of closely related variants (>98% sequence identity) of the same species, while MEX 15 segregated independently from MEX 32, the former constituting a distinct species among New World geminiviruses, and the latter being a variant, Texas pepper virus-Chiapas isolate (TPV-CPS) with 95% sequence identity to TPV-TAM. Results collectively indicated a geographic basis for phylogenetic relationships rather than a specific affiliation with tobacco as a natural host. MEX 15 is provisionally described as a new begomovirus, tobacco apical stunt virus, TbASV, whose closest CP relative is cabbage leaf curl virus, and ZIM isolates are provisionally designated as tobacco leaf curl virus, TbLCV-ZIM, a new Eastern Hemisphere begomovirus, which has as its closest relative, chayote mosaic virus from Nigeria.