Dr. Qi Huang

Research Plant Pathologist
{Beltsville, MD}


Development of Detection and Protection Technologies for Viruses and Bacteria of Major Significance to Ornamental and Nursery Crops


Identifies, detects, and gains a better understanding of genetic relationships and molecular basis of pathogenicity of selected bacterial pathogens to facilitate effective control of bacterial diseases of major significance to ornamental and agronomic crops. Current research interests include: conducting research on Xylella fastidiosa including genome characterization and specific detection and identification of ornamental strains, as well as genetic relationships among ornamental and non-ornamental strains of X. fastidiosa; and improving current detection and identification methods for the select agent pathogen Ralstonia solanacearum race 3 biovar 2.


Developed a quick, simple and efficient procedure for detecting X. fastidiosa in potential insect vectors. Demonstrated for the first time the association of X. fastidiosa with a leaf-scorch disorder in Japanese beech bonsai and in black oak in the United States. Showed the causal role of X. fastidiosa in oleander leaf scorch and the presence of the disease in various locations in Texas. Isolated strains of X. fastidiosa from porcelain berry (an invasive exotic), wild grape, and mulberry in a defined ecosystem, and determined genetic relationships to isolates from economic hosts such as grape. Participated in the annotation and analysis of the 8X draft genome of R. solanacearum race 3, biovar 2.


Develop a specific detection and identification method for woody ornamental strains of X. fastidiosa. Determine pathogenic relationships between ornamental and non-ornamental strains of X. fastidiosa. Determine the host range of R. solanacearum race 3 biovar 2 in ornamental crops, study inoculum thresholds and the effect of environmental factors on the virulence of the bacterium, and develop environmental friendly measures to control this pathogen.


Huang, Q., and Hartung, J. 2001. Cloning and sequence analysis of an infectious clone of Citrus yellow mosaic virus that can infect sweet orange via Agrobacterium-mediated inoculation. Journal of General Virology 82: 2549-2558.

Huang, Q., Li, W., and Hartung, J. S. 2003. Association of Xylella fastidiosa with leaf scorch in Japanese beech bonsai. Canadian Journal of Plant Pathology 25: 401-405.

Huang, Q. 2004. First report of Xylella fastidiosa associated with leaf scorch in black oak in Washington, D.C. Plant Disease 88: 224.

Huang, Q., and Sherald, J. L. 2004. Isolation and phylogenetic analysis of Xylella fastidiosa from its invasive alternative host, porcelain berry. Current Microbiology 48: 73-76.

Huang, Q., Brlansky, R. H., Barnes, L., Li, W. and Hartung, J. S. 2004. First report of oleander leaf scorch caused by Xylella fastidiosa in Texas. Plant Disease 88: 1049.

Gabriel, D. W., Allen, C. A., Schell, M., Denny, T., Greenberg, J., Duan, Y. P., Flores-Cruz, Z.,
Huang, Q., Clifford, J. M., Presting, G., Gonzalez, E. T., Reddy, J., Elphinstone, J., Swanson, J., Yao, J., Mulholand, V., Liu, L., Farmerie, W., Patnaikuni, M., Galogh, B., Norman, D., Alvarez, A., Castillo, J., Saddler, G., Walunas, T., Zhukov, A., and Mikhailova, N. 2006. Identification of open reading frames unique to a select Agent: Ralstonia solanacearum race 3, biovar 2. Molecular Plant-Microbe Interaction 19: 69-79.

Hammond, J., Hsu, H-T., Huang, Q., Jordan, R. L., Kamo, K. K., and Pooler, M. R. 2006. Transgenic approaches to disease resistance in ornamental crops. Journal of Crop Improvement 17: 155-210.

Huang, Q., Bentz, J. and Sherald, J. L. 2006. Fast, easy and efficient DNA extraction and one-step PCR for the detection of Xylella fastidiosa in potential insect vectors. Journal of Plant Pathology 88: 77-81.

DeStefano, D. A., Grybauskas, A. P., Sherald, J. L., Momen, B., Huang, Q. and Sullivan, J. H. 2007. Effect of the growth regulator Paclobutrazol on growth of the bacterial pathogen Xylella fastidiosa. Arboriculture and Urban Forestry 33: 246-252.

Huang, Q. 2007. Natural occurrence of Xylella fastidiosa in a commercial nursery in Maryland. Canadian Journal of Plant Pathology 29: 299-303.

Huang, Q. and Hartung, J.S. 2007. Construction of infectious clones for double stranded DNA viruses of plants using Citrus Yellow Mosaic Virus as an example. Methods in Molecular Biology 451: 525-534.

Li, R., Mock, R., Huang, Q., Abad, J., Hartung, J. S., and Kinard, G. 2008. A reliable and inexpensive method of nucleic acid extraction for the PCR-based detection of diverse plant pathogens. Journal of Virological Methods 154: 48-55.

Huang, Q. 2009. Specific detection and identification of Xylella fastidiosa strains causing oleander leaf scorch by polymerase chain reaction. Current Microbiology 58: 393-398.

Norman, D. J., Huang, Q., Yuen, J.M.F., Mangravita-Novo, A., and Byrne, D. 2009. Susceptibility of Geranium Cultivars to Ralstonia solanacearum. HortScience 44: 1-5.

Singh, R., Ferrin, D. M., and Huang, Q. 2010. First Report of Xylella fastidiosa associated with oleander leaf scorch in Louisiana. Plant Disease: 94: 274.

Huang, Q., and Lakshman, D.K. 2010. Effect of clove oil on plant pathogenic bacteria and bacterial wilt of tomato and geranium. Journal of Plant Pathology 92: 701-707.

Huang, Q., Yan, X., and Wang, J.-F. 2012. Improved biovar test for Ralstonia solanacearum. Journal of Microbiological Methods 88: 271-274.