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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Crop Diseases, Pests and Genetics Research » Research » Research Project #432290

Research Project: Identification of Novel Management Strategies for Key Pests and Pathogens of Grapevine with Emphasis on the Xylella Fastidiosa Pathosystem

Location: Crop Diseases, Pests and Genetics Research

2021 Annual Report


Accomplishments
1. Identification of a novel type of grapevine resistance to Xylella fastidiosa. Pierce’s disease of grapevine is caused by the lethal bacterium Xylella fastidiosa (Xf), which is transmitted from plant to plant by vectors such as the glassy-winged sharpshooter (GWSS). The bacteria-injection behavior by vectors can be visualized and quantified as a specific waveform (called the X wave) generated when studying GWSS feeding via electropenetrography (EPG). ARS researchers in Parlier, California, used EPG to compare GWSS feeding on Xf-resistant (wild Vitis champinii) versus Xf-susceptible (V. vinifera cv Chardonnay) grapevines. Results showed that insect vectors performed fewer X waves in fewer xylem cells, of overall shorter duration, on V. champinii than on ‘Chardonnay’. Thus, EPG can detect a novel type of grapevine resistance to vector inoculating behaviors. Future research will use EPG to screen grapevines for this novel type of resistance, leading to more durable resistance and less insecticide use in the future.

2. Characterization of grapevine physiological responses associated with infections by fungal and bacterial pathogens. Fungal diseases and Pierce’s disease of grapevines, caused by the bacterium Xylella fastidiosa (Xf), reduce yields over time. Progression of such diseases depends on specific plant-microbe interactions at the metabolite level, but information on the link between plant metabolism and aggressiveness of different pathogens are lacking. ARS researchers in Parlier, California, determined that phenolic compounds affect Xf behavior and biofilm formation, whereas fungal pathogen lesion lengths are positively correlated with phenolic levels and negatively correlated with terpenoid levels. Results suggest that grapevine varieties with lowered stem phenolic levels but greater terpenoid levels will be less affected by fungal canker pathogens and that reduced phenolic levels are linked with grapevine resistance to Pierce’s disease. Understanding of fungal stem pathogen-grapevine host interactions will be useful for identifying new grapevine varieties that provide improved resistance to fungal pathogens.

3. Vibrational communication of grapevine leafhoppers in California. Leafhoppers are a concern for grape growers in California due to direct feeding damage by piercing the leaves, transmission of plant pathogens, or both. Behavioral mating disruption is a viable option to manage leafhopper populations, but nothing was known about the mating communication and calling activity of most leafhopper species in vineyards. ARS researchers in Parlier, California, identified and described vibrational signals associated with mate selection behavior of Erasmoneura variabilis and Erythroneura ziczac, and evaluated the calling activity of these and another species (Homalodisca vitripennis) on grapevines in the field. Studies revealed that: distinct vibrational signals are used in pair formation; the pair formation process is divided in three communication phases; and leafhoppers in field populations sing at night and during the day. Results provide detailed descriptions of leafhopper communication signals that are relevant for future development of vibrational disruption as a novel method to suppress populations under field conditions.

4. DNA sequence resources for bacterial plant pathogens of economic importance. Xylella taiwanensis causes pear leaf scorch disease in Taiwan and X. fastidiosa is an important bacterial pathogen that causes plum leaf scald disease (PLSD) and phony peach disease in the southeastern United States. ARS researchers in Parlier, California, collaborated with scientists in Taiwan and Georgia to study the bacterial genomes using a metagenomic approach and next generation sequencing technology. A draft whole genome sequence of a PLSD strain was obtained, representing the first report of a whole genome sequence of a X. fastidiosa strain from plum. A small plasmid (a mobile genetic element of 2,104 base pairs) was found in X. taiwanensis which shared over 65% similarities to those from X. fastidiosa and other bacterial species. This is the first evidence of potential exchange of genetic material between bacterial species, which enhances research in bacterial virulence development and environmental adaptation.

5. Detection and description of a novel phage in “Candidatus Liberibacter asiaticus” (CLas). Candidatus Liberibacter asiaticus (CLas), a non-culturable alfa-proteobacterium, is associated with citrus Huanglongbing (HLB), a devastating disease threatening citrus production worldwide. ARS researchers in Parlier, California, collaborated with scientists in China to study the CLas phages that play important roles in the bacterial biology. Through the use of next generation sequencing technology, a novel phage was found which had a circular genome of 8,869 base pairs and eight open reading frames including two known genes coding for a replication initiation protein and a major capsid protein. Phylogenetic analysis revealed that the phage CLasMV1 belongs to the Microviridae family. The discovery and characterization of the CLasMV1 phage expanded the knowledge of CLas phages that have direct impact on HLB research and control.

6. Phenolic induction determined to be a common plant response to herbivory and pathogen infection. Plant production of phenolic compounds was hypothesized to be a common plant response to infection and infestation, but conflicting reports persisted to the contrary. ARS researchers in Parlier, California, utilized meta-statistical analyses on over 100 peer-reviewed research articles from 2008 to 2017 to determine whether induction of phenolic compounds was a consistent plant response to beneficial microbes, pathogens, or insects (either macerating or piercing-sucking). Phenolics were discovered to be induced when plants were exposed to all of these with the exception of piercing-sucking insects. These results provide information about plant physiological responses to infections by different pathogens, which relates to efforts to characterize grapevine and other plant infection processes by bacteria, fungi, nematodes, and viruses. Knowledge gained that phenolic induction is a consistent response to pests and microbes impacts future hypotheses about plant health and guides industrial research that utilizes plant chemical signatures for detection of pests and disease.


Review Publications
Lee, S.A., Burbank, L.P., Wallis, C.M., Rogers, E.E. 2020. Grapevine phenolic compounds influence cell surface adhesion of Xylella fastidiosa and bind to lipopolysaccharide. PLoS ONE. 15(10):e0240101. https://doi.org/10.1371/journal.pone.0240101.
Rattner, R., Thapa, S.P., Dang, T., Osman, F., Selvaraj, V., Maheshwari, Y., Pagliaccia, D., Espindola, A.S., Hajeri, S., Chen, J., Coaker, G., Vidalakis, G., Yokomi, R.K. 2021. Genome analysis of Spiroplasma citri strains from different host plants and its leafhopper vectors. BMC Genomics. 22:373. https://doi.org/10.1186/s12864-021-07637-8.
Yokomi, R.K., Rattner, R., Osman, F., Maheshwari, Y., Selvaraj, V., Pagliaccia, D., Chen, J., Vidalakis, G. 2020. Whole genome sequence of five strains of Spiroplasma citri isolated from different host plants and its leafhopper vector. BMC Research Notes. 13. Article 320. https://doi.org/10.1186/s13104-020-05160-9.
Backus, E.A., Guedes, R.N., Reif, K.E. 2021. AC-DC electropenetrography: fundamentals, controversies, and perspectives for pest management. Pest Management Science. 77(3):1132-1149. https://doi.org/10.1002/ps.6087.
Backus, E. A. Foreword. In: Panizzi, A., T. Lucini and P.L. Mitchell. Electronic Monitoring of the Feeding Behavior of Phytophagous True Bugs (Heteroptera). Vol. 6 in series Entomology in Focus. Springer Publ., Switzerland. Available: https://doi.org/10.1007/978-3-030-64674-5.
Reif, K.E., Backus, E.A. 2021. AC-DC electropenetrography unmasks fine temporal details of feeding behaviors for two tick species on unsedated hosts. Nature Scientific Reports. 11:2040. https://doi.org/10.1038/s41598-020-80257-6.
White, D., Backus, E.A., Marcus, I.M., Walker, S.L., Roper, M. 2021. Functional foregut anatomy of the blue–green sharpshooter illustrated using a 3D model. Scientific Reports. 11. Article 6536. https://doi.org/10.1038/s41598-021-85954-4.
Roddee, J., Backus, E.A., Wangkaree, J., Hangoonsong, Y. 2021. Alteration in the stylet probing behavior and host preference of the vector Matsumuratettix hiroglyphicus (Hemiptera:Cicadellidae) after infection with Sugarcane White Leaf Phytoplasma. Journal of Economic Entomology. 114(3):1081-1090. https://doi.org/10.1093/jee/toab059.
Zeilinger, A.R., Wallis, C.M., Beal, D., Sicard, A., Walker, M., Almeida, R.P. 2021. Non-linear dynamics of vector transmission of a plant pathogen: a test of theory and application to disease management. Ecosphere. 12(5):e03505. https://doi.org/10.1002/ecs2.3505.
Wallis, C.M. 2020. Determining roles of grapevine (Vitis spp.) stilbenoids on providing host resistance to root knot nematodes, Meloidogyne incognita. BMC Research Notes. 13:360. https://doi.org/10.1186/s13104-020-05201-3.
Wallis, C.M., Zeilinger, A.R., Sicard, A., Beal, D., Walker, A., Almeida, R.P. 2020. Role of phenolic compounds in imparting tolerance to Xylella fastidiosa in Pierce’s disease susceptible and resistant grapevines. PLoS One. 15(8):e0237545. https://doi.org/10.1371/journal.pone.0237545.
Backus, E.A., Shih, H. 2020. Do sharpshooters from around the world produce the same EPG waveforms? Comparison of waveform libraries from Xylella fastidiosa vectors Kolla paulula from Taiwan and Graphocephala atropunctata from California. Journal of Insect Science. 20(4). Article 7. https://doi.org/10.1093/jisesa/ieaa056.
Silva, P., Huang, J., Wulff, N., Krugner, R., Chen, J. 2020. Genome sequence resource of ‘Candidatus Liberibacter asiaticus’ strain 9PA from Brazil. Plant Disease. 105(1):199-201. https://doi.org/10.1094/PDIS-05-20-1018-A.
Wallis, C.M., Galameau, E. 2020. Phenolic compound induction in plant-microbe and plant-insect interactions: a meta-analysis. Frontiers in Plant Science. 11:580753. https://doi.org/10.3389/fpls.2020.580753.
Gordon, S.D., Krugner, R. 2021. Copulatory signaling and polygamy of glassy-winged sharpshooters (Hemiptera: Cicadellidae). Annals of the Entomological Society of America. 114(4):522-527. https://doi.org/10.1093/aesa/saab019.
Krugner, R., Gordon, S.D. 2021. Mating communication of the variegated leafhopper, Erasmoneura variabilis, with notes on vibrational signaling of other grapevine cicadellids in California. Annals of the Entomological Society of America. 114(4):528-537. https://doi.org/10.1093/aesa/saab024.
Stenger, D.C., Krugner, R. 2021. Insect-to-insect horizontal transmission of a phytoreovirus in the absence of an infected plant host. Virology. 562:87-91. https://doi.org/10.1016/j.virol.2021.07.006.