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

Bayhan, E., Ölmez-Bayhan, S., Ulusoy, M. R., & Brown, J. K. (2005). Effect of temperature on the biology of Aphis punicae (Passerini) (Homoptera: Aphididae) on Pomegranate. Environmental Entomology, 34(1), 22-26.

Abstract:

The effect of temperature on development time, reproductive capacity, and rate of survival for Aphis punicae was studied at five different (constant) temperatures (17.5, 20, 22.5, 25, and 27.5°C). The development period for immature instar stages ranged from 11.72 d at 17.5°C to 4.30 d at 27.5°C. The lowest developmental threshold was 11.8°C, and the thermal constant (K) was 66.4 DD. The percentage survivorship of immature stages varied from 72.0 to 90.0% over a temperature range of 17.5-27.5°C. The average longevity of adult females was 16.50, 17.17, 18.16, 12.04, and 8.91 d at temperatures of 17.5, 20, 22.5, 25, and 27.5°C, respectively. The average number of offspring produced by a single female was 14.65, 22.68, 31.34, 21.31, and 11.27 at temperatures of 17.5, 20, 22.5, 25, and 27.5°C, respectively. The greatest rm (0.3292) was observed at 25°C. The optimal temperature for A. punicae growth, development, and reproduction was 22.5-25°C.

Costa, H. S., Costa, H. S., Westcot, D. M., Westcot, D. M., Ullman, D. E., Ullman, D. E., Rosell, R. C., Rosell, R. C., Brown, J. K., Brown, J. K., Johnson, M. W., & Johnson, M. W. (1996). Virus-like particles in the mycetocytes of the sweetpotato whitefly, Bemisia tabaci (homoptera, aleyrodidae). Journal of Invertebrate Pathology, 67(2), 183-186.
Chu, D., Zhang, Y., Brown, J. K., Cong, B., Xu, B., Wu, Q., & Zhu, G. (2006). The introduction of the exotic Q biotype of Bemisia tabaci from the Mediterranean region into China on ornamental crops. Florida Entomologist, 89(2), 168-174.

Abstract:

The Q biotype of Bemisia tabaci (Gennadius), which has been described from the Mediterranean/North African region, was identified for the first time infesting ornamental crop species in several locations in China. Identification and partial distributions of the exotic B biotype and the recently introduced Q biotype in China were established by using the mitochondrial cytochrome oxidase I gene (mtCOI) as a molecular marker. Collections of B. tabaci were made from representative geographical locations and plant hosts in different provinces of China. MtCOI sequence analysis revealed that collections from Beijing [AY582872, AY589499], Yunnan [AY518189, AY587516], and Henan [AY587514] shared >99.6% sequence identity with the Q biotype from Spain [AY587513, AY562216, AY596950]. The Q type from China shared 98.9-99.4% nucleotide sequence identity with Q-like relatives of B. tabaci described from Israel [AY518191, AY582869]. Phylogenetic analyses indicated that certain B. tabaci populations that are present in China are the Q biotype, and that the Q biotype now in China may have originated from Spain or other nearby locations where the Q biotype has been identified. This is the first report of the introduction of the Q biotype from the Mediterranean region into China. The specific outcomes of the Q biotype as an invasive species in Asia are presently unknown. Certain Q biotype populations from Spain have been reported to exhibit resistant to neonicotinoid insecticides, which are commonly used for controlling this pest and virus vector in ornamental and field crops. Thus, the close monitoring of the Q biotype in China and elsewhere, particularly where commercial plants are grown for export or received for importation, respectively, is essential to avoid the further geographical expansion of the habitat of the Q biotype.

Brown, J. K., Idris, A. M., Alteri, C., & Stenger, D. C. (2002). Emergence of a new Cucurbit-infecting begomovirus species capable of forming viable reassortants with related viruses in the Squash leaf curl virus cluster. Phytopathology, 92(7), 734-742.

PMID: 18943269;Abstract:

Cucurbit leaf curl virus (CuLCV), a whitefly-transmitted geminivirus previously partially characterized from the southwestern United States and northern Mexico, was identified as a distinct bipartite begomovirus species. This virus has near sequence identity with the previously partially characterized Cucurbit leaf crumple virus from California. Experimental and natural host range studies indicated that CuLCV has a relatively broad host range within the family Cucurbitaceae and also infects bean and tobacco. The genome of an Arizona isolate, designated CuLCV-AZ, was cloned and completely sequenced. Cloned CuLCV-AZ DNA A and B components were infectious by biolistic inoculation to pumpkin and progeny virus was transmissible by the whitefly vector, Bemisia tabaci, thereby completing Koch's postulates. CuLCV-AZ DNA A shared highest nucleotide sequence identity with Squash leaf curl virus-R (SLCV-R), SLCV-E, and Bean calico mosaic virus (BCaMV) at 84, 83, and 80%, respectively. The CuLCV DNA B component shared highest nucleotide sequence identity with BCaMV, SLCV-R, and SLCV-E at 71, 70, and 68%, respectively. The cis-acting begomovirus replication specificity element, GGTGTCCTGGTG, in the CuLCV-AZ origin of replication is identical to that of SLCV-R, SLCV-E, and BCaMV, suggesting that reassortants among components of CuLCV-AZ and these begomoviruses may be possible. Reassortment experiments in pumpkin demonstrated that both reassortants of CuLCV-AZ and SLCV-E A and B components were viable. However, for CuLCV-AZ and SLCV-R, only one reassortant (SLCV-R DNA A/CuLCV-AZ DNA B) was viable on pumpkin, even though the cognate component pairs of both viruses infect pumpkin. These results demonstrate that reassortment among sympatric begomovirus species infecting cucurbits are possible, and that, if generated in nature, could result in begomoviruses bearing distinct biological properties.

Popovski, S., Kollenberg, M., Gorovitz, R., Brown, J., Cicero, J., Czosnek, H., Winter, S., & Ghanim, M. (2012). Implication of Bemisia tabaci heat shock protein 70 in begomovirus - whitefly interactions. J. Virol, 86, 13241-13252.

doi:10.1128/JVI.00880-12.