Dr. Nabil Killiny

Dr. Nabil Killiny

Program Emphasis

Research interests:
My research interests focus on the biology of pathogen-vector interfaces. Interactions between vector and pathogen vary from simple mechanical transmission to intricate interactions where the pathogens must develop and multiply within vectors. Our research focuses on the molecular characterization of different transmission systems including pathogens which colonize their vectors and either circulative or non-circulative in their vectors.
1-The circulative multiplicative systems:Spiroplasma citri/Circulifer haematoceps. Spiroplasmas ingested via phloem-sap feeding traverse the leafhopper gut wall, move into the haemolymph and invade the salivary glands, where they are introduced into the phloem of new host plant.
2- The multiplicative foregut-borne system: Xylella fastidiosa/Graphocephala atropunctataX. fastidiosa cells colonize only the cibarium and precibarium of the sharpshooter vector’s foregut. The vector acquires and inoculates cells in the xylem sap of host plants during feeding.
3- The circulative multiplicative system: Candidatus Liberibacter asiaticus/Diaphorina citri. The pathogen is phloem restricted in plant and transmitted by the Asian citrus psyllid.
Research goals:

The molecular characterization of the interactions between pathogen and its vector is important to understand the behavior of this pathogen and then target the transmission process using the appropriate strategy. Furthermore, in the context of sustainable agriculture we should use friendly environmental solutions. For that, developing alternative strategies based on the understanding pathogen-vector interactions is necessary.


Ph.D. in Biological and Medical Sciences; with particular focus on Pathogen-Vector Molecular Interactions, University of Bordeaux 2 and INRA, Bordeaux, France. 2005.

Dissertation title: “Spiroplasma citri and its insect vector Circulifer haematoceps: Proteins-proteins interaction and identification of a protein marker of transmission

Past Positions

Post Doctoral Researcher Nov 2006-Dec 2010.  University of California, Berkeley, CA


Vector-Pathogen interactions

Refereed Publications


Killiny, N. (2017). Metabolite signature of the phloem sap of fourteen citrus varieties with different degrees of tolerance to Candidatus Liberibacter asiaticus. Physiological and Molecular Plant Pathology 97, 20-29.

Killiny, N. and Kishk, A. (2017) Delivery of dsRNA through topical feeding for RNA interference in the citrus sap piercing-sucking hemipteran, Diaphorina citri. Insect Biochemistry and Physiology. 95, e21394.

Killiny, N. and Nehela, Y. (2017) Metabolomic response to huanglongbing: Role of carboxylic compounds in citrus response to Candidatus Liberibacter asiaticus and its vector, Diaphorina citri. Molecular Plant-Microbe Interactions. 30, 666–678.

Killiny, N. and Nehela, Y. (2017) One target, two mechanisms: the impact of Candidatus Liberibacter asiaticus and its vector, Diaphorina citri on citrus leaf pigments. Molecular Plant-Microbe Interactions. 30, 543–556.

Killiny, N., and Jones, S.E. (2017). Profiling of volatile organic compounds released from individual intact juvenile and mature citrus leaves. Journal of Plant Physiology 208, 47-51.

Killiny, N., Hijaz, F., Ebert, T., and Rogers, M.E. (2017). Plant bacterial pathogen manipulates the energy metabolism of its insect vector. Applied and Environmental Microbiology 83, e03005-03016.

Killiny, N., Hijaz, F., El-Shesheny, I., Alfaress, S., Jones, S.E., and Rogers, M.E. (2017). Metabolomic analyses of the haemolymph of the Asian citrus psyllid, Diaphorina citri, the vector of huanglongbing. Physiological Entomology, 42, 134–145.

Killiny, N., Hijaz, F., Harper, S.J., and Dawson, W.O. Effects of Citrus tristeza closterovirus infection on phloem sap and released volatile organic compounds in Citrus macrophylla. Physiological and Molecular Plant Pathology. 98, 25-36.

Killiny, N., Nehela, Y., Hijaz, F. and Vincent, C. I. (2017) A plant pathogenic bacterium exploits the tricarboxylic acid cycle metabolic pathway of its insect vector. Virulence. doi:10.1080/21505594.2017.1339008.

Killiny, N., Valim, M. F., Jones, S. E., Hijaz, F., Gmitter, F. G. and Grosser, J. W. (2017) Metabolically speaking: reasons behind the tolerance of 'SugarBelle' mandarin hybrid to huanglongbing. Plant Physiology and Biochemisery 116, 36-47.

Kishk, A.A., Anber, H.A, Abdel-Raof, T.K., El-Sherbeni, A.D., Hamed, S., Gowda, S., and Killiny, N. (2017). RNA interference of carboxyesterases cause nymph mortality in the Asian citrus psyllid, Diaphorina citri. Archives of Insect Biochemistry and Physiology 94, e21377.

Lu, Z., Hu, H., and Killiny, N. (2017). Proteomic maps of subcellular protein fractions of the Asian citrus psyllid Diaphorina citri, the vector of citrus huanglongbing. Physiological Entomology. 42, 36-64.

Lu, Z. and Killiny, N. (2017) Huanglongbing pathogen Candidatus Liberibacter asiaticus exploits the energy metabolism and host defence responses of its vector Diaphorina citri. Physiological Entomology. doi:10.1111/phen.12198.

Martini, X., Hughes, M. A., Killiny, N., George, J., Lapointe, S., Smith, J. A. and Stelinski, L. L. (2017) The Fungus Raffaelea lauricola Modifies Behavior of Its Symbiont and Vector, the Redbay Ambrosia Beetle (Xyleborus Glabratus), by Altering Host Plant Volatile Production. Journal of Chemical Ecology. 43, 519-531.

Valim, M. F. and Killiny, N. (2017) Occurrence of free fatty acids in the phloem sap of different citrus varieties. Plant Signaling and Behavior. doi: 10.1080/15592324.2017.1327497. PubMed PMID: 28532234.

Yu, X., Gowda, S., and Killiny, N. (2017). Double-stranded RNA delivery through soaking, mediates silencing of the muscle protein 20 and increases mortality to the Asian citrus psyllid, Diaphorina citri. Pest Management Science. doi: 10.1002/ps.4549. PubMed PMID: 28195429.


Alfaress, S., Hijaz, F., and Killiny, N. (2016). Chemical composition of cornicle secretion of the brown citrus aphid Toxoptera citricida. Physiological Entomology 41, 38-47.

El-Borai, F., Killiny, N., and Duncan, L.W. (2016). Concilience in entomopathogenic nematode responses to water potential and their geospatial patterns in Florida. Frontiers in Microbiology 7, 356.

El-Shesheny, I., El-Hawary, I., Mesbah, I., and Killiny, N. (2016a). Comparative proteomic analysis between fifth-instar nymphs and adults of Asian citrus psyllid, Diaphorina citri. Physiological Entomology 41, 162-184.

El-Shesheny, I., Hijaz, F., El-Hawary, I., Mesbah, I., and Killiny, N. (2016b). Impact of different temperatures on survival and energy metabolism in the Asian citrus psyllid, Diaphorina citri Kuwayama. Comparative Biochemistry and Physiology a-Molecular & Integrative Physiology 192, 28-37.

Harper, S.J., Killiny, N., Tatineni, S., Gowda, S., Cowell, S.J., Shilts, T., and Dawson, W.O. (2016). Sequence variation in two genes determines the efficacy of transmission of citrus tristeza virus by the brown citrus aphid. Archives of Virology 161, 3555-3559.

Hijaz, F., and Killiny, N. (2016). A gas chromatography-mass spectrometry method for the determination of delta-aminolevulinic acid in plant leaves. Journal of Chromatography A 1447, 57-63.

Hijaz, F., Lu, Z., and Killiny, N. (2016). Effect of host-plant and infection with 'Candidatus Liberibacter asiaticus' on honeydew chemical composition of the Asian citrus psyllid, Diaphorina citri. Entomologia Experimentalis Et Applicata 158, 34-43.

Hijaz, F., Manthey, J.A., Van Der Merwe, D., and Killiny, N. (2016). Nucleotides, micro- and macro-nutrients, limonoids, flavonoids, and hydroxycinnamates composition in the phloem sap of sweet orange. Plant Signaling & Behavior 11.

Hijaz, F., Nehela, Y., and Killiny, N. (2016). Possible role of plant volatiles in tolerance against huanglongbing in citrus. Plant Signaling & Behavior 11.

Killiny, N. (2016). Generous hosts: What makes Madagascar periwinkle (Catharanthus roseus) the perfect experimental host plant for fastidious bacteria? Plant Physiology and Biochemistry 109, 28-35.

Killiny, N. (2016). Metabolomic comparative analysis of the phloem sap of curry leaf tree (Bergera koenegii), orange jasmine (Murraya paniculata), and Valencia sweet orange (Citrus sinensis) supports their differential responses to Huanglongbing. Plant Signaling & Behavior 11, e1249080

Killiny, N., Harper, S.., Alfaress, S., El Mohtar, C., and Dawson, W.O. (2016). Minor coat and heat shock proteins are involved in the binding of Citrus tristeza virus to the foregut of its aphid vector, Toxoptera citricida. Applied and Environmental Microbiology 82, 6294-6302.

Killiny, N., and Hijaz, F. (2016). The occurrence of non-protein amino acids in the phloem sap of different citrus varieties. Florida State Horticulture Society.129, 45-50.

Killiny, N., and Hijaz, F. (2016). Amino acids implicated in plant defense are higher in Candidatus Liberibacter asiaticus-tolerant citrus varieties. Plant Signaling & Behavior 11, e1171449.

Nehela, Y., Hijaz, F., Elzaawely, A.A., El-Zahaby, H.M., and Killiny, N. (2016). Phytohormone profiling of the sweet orange (Citrus sinensis (L.) Osbeck) leaves and roots using GC-MS-based method. Journal of Plant Physiology 199, 12-17.

Pelz-Stelinski, K.S., and Killiny, N. (2016). Better Together: Association With 'Candidatus Liberibacter asiaticus' increases the reproductive fitness of its insect vector, Diaphorina citri (Hemiptera: Liviidae). Annals of the Entomological Society of America 109, 371-376.


Tiwari, S., Liu, B., Mann, R. S., Killiny, N. and Stelinski, L. L. 2015. Effects of cold-acclimation, pathogen infection, and varying temperatures on insecticide susceptibility, feeding, and detoxifying enzyme levels in Diaphorina citri (Hemiptera: Liviidae). Florida entomologist. 98:870-879.

Killiny, N. and Hijaz F. 2015. Chemical Composition of Xylem Sap from Citrus sinensis L. Osbeck (Sweet Orange). Proceeding of Florida State Horticulture Society. 128:***.


Cheng Y, Wang XY, Hu H, Killiny N, Xu JP. A Hypothetical Model of Crossing Bombyx mori Nucleopolyhedrovirus through Its Host Midgut Physical Barrier. PLoS One. 2014 Dec 12;9(12):e115032. doi: 10.1371/journal.pone.0115032. eCollection 2014. PubMed PMID: 25502928; PubMed Central PMCID: PMC4264868.

Killiny N, Hajeri S, Tiwari S, Gowda S, Stelinski LL. Double-stranded RNA uptake through topical application, mediates silencing of five CYP4 genes and suppresses insecticide resistance in Diaphorina citri. PLoS One. 2014 Oct 20;9(10):e110536. doi: 10.1371/journal.pone.0110536. eCollection 2014. PubMed PMID: 25330026; PubMed Central PMCID: PMC4203802.

Hijaz F, Killiny N. Collection and chemical composition of phloem sap from Citrus sinensis L. Osbeck (sweet orange). PLoS One. 2014 Jul 11;9(7):e101830. doi: 10.1371/journal.pone.0101830. eCollection 2014. PubMed PMID: 25014027; PubMed Central PMCID: PMC4094394.

Hajeri S, Killiny N*, El-Mohtar C, Dawson WO, Gowda S. Citrus tristeza virus-based RNAi in citrus plants induces gene silencing in Diaphorina citri, a phloem-sap sucking insect vector of citrus greening disease (Huanglongbing). J Biotechnol. 2014 Apr 20;176:42-9. doi: 10.1016/j.jbiotec.2014.02.010. Epub 2014 Feb 23. PubMed PMID: 24572372.
* Authors contributed equally to this work.

Baccari C, Killiny N, Ionescu M, Almeida RP, Lindow SE. Diffusible signal factor-repressed extracellular traits enable attachment of Xylella fastidiosa to insect vectors and transmission. Phytopathology. 2014 Jan;104(1):27-33. doi:10.1094/PHYTO-06-13-0151-R. PubMed PMID: 24571393.

Killiny N, Almeida RP. Factors affecting the initial adhesion and retention of the plant pathogen Xylella fastidiosa in the foregut of an insect vector. Appl Environ Microbiol. 2014 Jan;80(1):420-6. doi: 10.1128/AEM.03156-13. Epub 2013 Nov 1. PubMed PMID: 24185853; PubMed Central PMCID: PMC3910991.

Parker JK, Wisotsky SR, Johnson EG, Hijaz FM, Killiny N, Hilf ME, De La Fuente
L. Viability of 'Candidatus Liberibacter asiaticus' prolonged by addition of citrus juice to culture medium. Phytopathology. 2014 Jan;104(1):15-26. doi: 10.1094/PHYTO-05-13-0119-R. PubMed PMID: 23883155.

Killiny, N., Hernandez Martinez, R., Korsi Dumenyo, C., Cooksey, D. A., and Almeida, R.P.P. 2013. The Exopolysaccharide of Xylella fastidiosa is Essential for Biofilm Formation, Plant Virulence and Vector Transmission. Molecular Plant-Microbe interactions. 26: 1044-1053.

Rashed, A., Kwan, J., Baraff, B., Ling, D., Daugherty, M.P., Killiny, N., and Almeida, R.P.P. 2013. Relative susceptibility of Vitis vinifera cultivars to vector-borne Xylella fastidiosa through time. PLoS ONE. 8: e55326.

El-Shesheny, I., Hajeri, S., El-Hawary, I., Gowda, S., Killiny, N. 2013. Silencing abnormal wing disc gene of the Asian citrus psyllid, Diaphorina citri disrupts adult wing development and increases nymph mortality. PLoS ONE. 8: e65392.

Hijaz, F., El-Shesheny, I., and Killiny, N. 2013. Herbivory by the insect Diaphorina citri induces greater change in citrus plant volatile than does by Cadidatus Liberibacter asciaticus. Plant Signaling & Behavior 8: e25677.

Tiwari, S., Killiny, N., and Stelinski L. L. 2013. Dynamic Insecticide Susceptibility Changes in Florida Populations of Diaphorina citri (Hemipetra: Psyllidae). Journal of Economic Entomology. 106: 393-9.

Tiwari, S., Killiny, N., Mann, R. S., Wenninger, E. J. and Stelinski L. L. 2013. Abdominal color of the Asian citrus psyllid, Diaphorina citri, is associated with susceptibility to various insecticides. Pest Management Science. 69: 535-41.

Almeida, R.P.P., Killiny, N., Newman, K.L., Chatterjee, S., Ionescu, M. and Lindow, S.E. 2012. Contribution of rpfB to cell-cell signal synthesis, virulence, and vector transmission of Xylella fastidiosa. Molecular Plant-Microbe Interactions 25: 453-462.

Killiny, N., Rashed, A., and Almeida, R.P.P. 2012. Disrupting the transmission of a vector-borne plant pathogen. Applied and Environmental Microbiology 78: 638-643.

Matsumoto, A., Huston, S. L., Killiny, N. and Igo, M. M. 2012. XatA, an AT-1 autotransporter important for the virulence of Xylella fastidiosa Temecula1. Microbiologyopen. 1:33-45.

Killiny, N. and Almeida, R. P.P. 2011. Gene Regulation Mediates Host Specificity of a Bacterial Pathogen. Environmental Microbiology Reports. 6:791-97.

A. Rashed, N. Killiny, J. Kawn, R. P. P. Almeida. 2011. Background matching behaviour and pathogen acquisition: Plant site preference does not predict the bacterial acquisition efficiency of vectors. Arthropod-Plant Interactions. 5: 97-106.

N. Killiny, S. Prado, and R. P. P. Almeida. 2010. Chitin utilization by the insect--transmitted bacterium Xylella fastidiosa. Applied and Environmental Microbiology. 76:6134-40.

S. chattergee*, N. Killiny*, R. P. P. Almeida and S. E. Lindow. 2010. Role of Cyclic di-GMP in Xylella fastidiosa Biofilm Formation, Plant Virulence and Insect Transmission. Molecular Plant-Microbe interactions. 23:1356-63. * Authors contributed equally to this work.

N. Killiny and R. P. P. Almeida. 2009. Host structural polysaccharide induces vector transmission of a bacterial plant pathogen. Proceedings of the National Academy of Science.106:22416-20.

N. Killiny and R. P. P. Almeida. 2009. Xylella fastidiosa afimbrial adhesins are associated with cell attachment to leafhopper vectors and transmission to plants. Applied and Environmental Microbiology. 75:521-8

2008 and before
C. Saillard, P. Carle, S. Duret-Nurbel, R. Henri, N. Killiny, S. Carrère, J. Gouzy, J. M. Bové, J. Renaudin and X. Foissac. 2008. x. BMC Genomics. 9:195

N. Killiny, B. Batailler, X. Foissac and C. Saillard 2006.Identification of a Spiroplasma citri hydrophilic protein associated with insect transmissibility Microbiology. 152, 1221-1230.

N. Killiny, M. Castroviejo and C. Saillard. 2005. Spiroplasma citri spiralin acts in vitro as a lectin binding to glycoproteins from its insect vector Circulifer haematoceps. Phytopatholgy. 95: 541-548.