Bacterial blight - Xanthomonas oryzae pv. oryzae
Effective: August 11, 2011
Taxonomic Position: Xanthomonadales : Xanthomonadaceae
Pest Type: Bacteria
Pest Code (NAPIS): FBZAXBM
These Approved Methods are appropriate for: 2025, 2024, 2023, 2022, 2021, 2020, 2019, 2018, 2017, 2016, 2015
Pest Information
CAPS Pest Datasheet: https://download.ceris.purdue.edu/file/3055
Pest Tracker: https://pesttracker.org/pest/FBZAXBM
Hosts Identified in the CAPS Host Matrix:
Rice
Pest is vectored by:

No known vector.

Survey

Approved Method(s)
Method Detail NAPIS Survey Method
Visual Collect symptomatic leaf samples. For a preliminary indications of seed infection, look for bacterial streaming (Singh and Rao, 1977) 3031 - General Visual Observation

Survey Recommendations
The following are recommendations for executing the survey using the approved methods for pest surveillance. The recommendations are developed through literature review and consultation with subject matter experts.
Signs:

Bacteria "ooze" out of water pores on hydathodes with bacterial blight.

Symptoms:

Bacterial blight appears on leaves of young plants, after planting out, as pale-green to gray-green and water-soaked streaks near the leaf tip and margins. These lesions coalesce and become yellowish-white with wavy edges. Lesions become dry and wilted (a symptom known as "kresek"). Seed may be discolored and poorly filled with bacterial blight.

Key Diagnostic or Identification

Approved Method(s)
ID/Diagnostic:
1. Morphological:

Colony morphology: The pathogen is difficult to isolate directly from plant material and seed due to slow growth of bacterium and overgrowth by other organisms. Contaminants may also be of a yellow color (e.g., Pantoea agglomerans and Xanthomonas-like saprophytic bacteria). Isolation from symptomatic material should be completed as soon as possible after collection of samples. Plant parts showing fresh symptoms preferably with bacterial exudates should be selected for isolation if available. See EPPO (2007) for additional detail about pathogen isolation from plant material and seeds.

Isolation of Xanthomonas from symptomatic material can be performed using peptone sucrose agar (PSA), nutrient broth yeast extract medium (NBY), growth factor (GF) agar, modified Wakimoto"s agar (without the ferrous sulfate), and various semi-selective media (Agarwal et al., 1989; Mew and Mistra, 1994; Sakthivel et al., 2001; EPPO, 2007). Growth is very slow on nutrient agar (NA) (EPPO, 2007).

Ming et al. (1991) developed a semi-selective medium, called XOS, to isolate both Xanthomonas oryzae pathovars from rice seed.

Gnanamanickam et al. (1994) tested three strains for growth on TZC, WF-P, YCM, YAT, MXO, and XOS semi-selective media. Results varied for each isolate used, but worked best when using monoclonal antibodies to confirm the genus and pathovar.

2. Serological: An ELISA test is available for Xanthomonas at the genus level for primary screening. A positive does not indicate Xanthomonas oryzae pv. oryzicola). The ID must be confirmed by other methods.

Monoclonal antibodies: Genus and pathovar specific antibodies can be used in an ELISA reaction on presumptive positives (Alvarez et al., 1985; Benedict et al., 1989).
Mistaken Identities:

In the early stage of disease, the symptoms are similar to narrow brown leaf spot. At the later stage, when the streaks have coalesced, symptoms of bacterial blight and bacterial leaf streak are similar. The shape of the edges of the lesions differs; straight in leaf streak and wavy in leaf blight. X. oryzae pv. oryzicola may be distinguished from X. oryzae pv. oryzae by colony morphology in typical isolates, strong starch and gelatin hydrolysis, and by biochemical and molecular methods.

In Progress / Literature-based Diagnostics:

Pathogenicity: Isolates can be tested for pathogenicity on susceptible rice cultivars. For X. oryzae pv. oryzae use 30 to 45 day-old IR24 or IR8 (International Rice Institute) or local popular varieties with known susceptibility to bacterial blight. Leaf clipping and spray inoculation methods are available for inoculations (Kauffman et al., 1973; Cottyn et al., 1994b; EPPO, 2007). Nino-Liu et al. (2005) inoculated plants by dipping them in bacterial mixture and incubating in a growth chamber. Symptoms developed a 6-day period. Fatty Acid Profiles: Fatty acid profiles allow identification at the genus level only (Swings et al., 1990), so this analysis is not recommended a diagnostic method. Molecular: PCR/BIO-PCR: Vera Cruz et al. (1995) and Vera Cruz et al. (1996) compared Rep-PCR using repetitive DNA sequences with Restriction Fragment Length Polymorphism (RFLP). Leach et al. (1990) used a repetitive DNA sequence (pJEL101) to distinguish X. oryzae pv. oryzae from other pathovars and species of Xanthomonas. PCR assays using primers that amplify internal fragments IS 1112 and IS 1113 of X. oryzae pv. oryzae (Cottyn et al., 1994; Alvarez et al., 1997) have been used as well. Sakthivel et al. (2001) developed a PCR technique to detect X. oryzae pv. oryzae in rice seed. A combined biological and enzymatic amplification (BIO-PCR) technique was used to detect the pathogen in naturally infected seed. Gonzalez et al. (2007) found that X. oryzae pv. oryzae African and Asian strains were genetically different from each other by using RFLP, fluorescent amplified fragment length polymorphism (FAFLP) and repetitive sequence-based polymerase chain reaction. Real-time PCR: Zhao et al. (2007) developed a real-time PCR to detect X. oryzae pv. oryzae and can distinguish it from X. oryzae pv. oryzicola. Liao et al. (2003) developed a real-time PCR that can distinguish the two pathovars. Computational Genomics/Multiplex PCR: Lang et al. (2010) used a computational genomics pipeline to compare sequenced genomes of Xanthomonas species to identify regions for development of highly specific diagnostic markers. A suite of primers were selected to monitor different loci and to distinguish the rice bacterial blight and leaf streak pathogens. A subset of primers were combined into a multiplex PCR to accurately distinguish the two rice pathogens in a geographically different collection from other xanthomonads and other plant pathogenic and plant-or seed associated bacteria.

Notes:

X. oryzae pv. oryzae was detected in Louisiana and Texas. Strains were of low virulence compared to Asian strains (Jones et al., 1989) Discussion with the authors indicates that this find should be a new pathovar and has not been found since they have stopped planting susceptible hosts. Xanthomonas oryzae is on the Select Agent List.

References
  1. Agarwal, P.C., Mortensen, C.N., and Mathur, S.B. 1989. Seedborne disease and seed health testing of rice. Technical Bulletin No. 3/Phytopathological Papers No. 30. Danish Government Institute of Seed Pathology for Developing Countries and CAB International Mycological Institute.
  2. Alvarez, A.M., Benedict, A.A., and Mizumoto, C.Y. 1985. Identification of xanthomonads and grouping of strains of Xanthomonas campestris pv. campestris with monoclonal antibodies. Phytopathology 75: 722-728.
  3. Alvarez, A.M., Rehman, F.U., and Leach, J.E. 1997. Comparison of serological and molecular methods for detection of Xanthomonas oryzae pv. oryzae in rice seed. In: Seed Health Testing: Progress Towards the 21st Century. J.D. Hutchins and J.C. Reeves (eds.). pp. 175-183.
  4. Benedict, A.A., Alvarez, A.M., Berestecky, J., Imanaka, W., Mizumoto, C.Y., Pollard, L.W., Mew, T.W., and Gonzalez, C.F. 1989. Pathovar-specific monoclonal antibodies for Xanthomonas campestris pv. oryzae and for Xanthomonas campestris pv. oryzicola. Phytopathology 79: 322-328.
  5. Cottyn, B., Bautista, A.T., Nelson, R.J., Leach, J.E., Swings, J., and Mew, T.W. 1994. Polymerase chain reaction amplification of DNA from bacterial populations of rice using specific oligonucleotide primers. International Rice Research Note 19: 30-32.
  6. Cottyn, B., Cerez, M.T., and Mew, T.W. 1994b. Chapter 7: Bacteria. In: A Manual of Seed Health Testing. T.W. Mew and J.K. Mistra (Eds.). pp. 322-328. IRRI, Manila.
  7. EPPO. 2007. Xanthomonas oryzae: Diagnostics. Volume 37 (3), pages 543-553.
  8. Gnanamanickam, S.S., Shigaki, T., Medalla, E.S., Mew, T.W., and Alvarez, A.M. 1994. Problems in detection of Xanthomonas oryzae pv. oryzae in rice seed and potential for improvement using monoclonal antibodies. Plant Disease 78: 173-178.
  9. Gonzalez, C., Szurek,B., Marceau, C., Mathieu, T., Sére, Y., and Verdier, V. 2007. Molecular and pathotypic characterization of new Xanthomonas oryzae strains from west Africa. Molecular Plant-Microbe Interactions 20(5): 534-546.
  10. Jones, R.K., Barnes, L.W., Gonzalez, C.F., Leach, J.E., Alvarez, A.M., and Benedict, A.A. 1989. Identification of low-virulence strains of Xanthomonas campestris pv. oryzae in the United States. Phytopathology 79(9): 984-990.
  11. Kauffman, H.E., Reddy, A.P.K., Hsieh, S.P.Y., and Merca, S.D. 1973. An improved technique for evaluating resistance in rice varieties to Xanthomonas oryzae. Plant Disease Reporter 57: 537-541.
  12. Lang, J.M., Hamilton, J.P., Diaz, M.G.Z., Van Sluys, M.A., Burgos, M.R.G., Vera Cruz, C.M., Buell, C.R. Tisserat, N.A., and Leach, J.E. 2010. Genomics-based diagnostic marker development for Xanthomonas oryzae pv. oryzae and X. oryzae pv. oryzicola. Plant Disease 94: 311-319.
  13. Leach, J.F., White, F.F., Rhoads, M.L., and Leung, H. 1990. Repetitive DNA sequence differentiates Xanthomonas campestris pv. oryzae from other pathovars of X. campestris. Molecular Plant-Microbe Interactions 3(4): 238-246.
  14. Liao, X., Zhu, S., Zhao, W., Luo, K., and Qi, Y. 2003. Detection and identification of Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola by real-time fluorescent PCR. Wei Sheng Wu Xue Bao 43(5): 626-634. English Abstr.
  15. Mew, T.W., and Misra, J.K. 1994. A Manual of Rice Seed Health Testing. IRRI. Manila.
  16. Ming, D., Ye, H.Z., Schaad, N.W., and Roth, D.A. 1991. Selective recovery of Xanthomonas spp. from rice seed. Phytopathology 81(11): 1358-1363.
  17. Nino-Liu D.O., Ronald P.C., and Bogdanove A.J. 2005. A Simple Method of Mass Inoculation of Rice Effective for Both Pathovars of Xanthomonas oryzae, and the Construction of Comparable Sets of Host cDNA Libraries Spanning Early Stages of Bacterial Leaf Blight and Bacterial leaf Streak. Journal of Phytopathology 153:500-504.
  18. Sakthivel, N., Mortensen, C.N., and Mathur, S.B. 2001. Detection of Xanthomonas oryzae pv. oryzae in artificially inoculated and naturally infected rice seeds and plants by molecular techniques. Appl. Microbiol. Biotechnol. 56: 435-441.
  19. Singh, R.A., and Rao, M.H.S. 1977. A simple technique for detecting Xanthomonas oryzae in rice seeds. Seed Science and Technology 5: 123-127.
  20. Swings, J., Van Den Mooter, M., Vauterin, L., Hoste, B., Gillis, M., and Mew, T.W. et al. 1990. Reclassification of the causal agents of bacterial blight (Xanthomonas campestris pv. oryzae) and bacterial leaf streak (Xanthomonas campestris pv. oryzicola) of rice as pathovars of Xanthomonas oryzae ex Ishiyama 1922) sp. nov., nom. rev. International Journal of Systematic Bacteriology 40: 301-311.
  21. Vera Cruz, C.M., Ardales, E.Y., Skinner, D.Z., Talag, J., Nelson, R.J., Louws, F.J., Leung, H., Mew, T.W., and Leach, J.E. 1996. Measurement of haplotype variation in Xanthomonas oryzae pv. oryzae within a single field by Rep-PCR and RFLP analyses. Phytopathology 86: 1352-1359.
  22. Vera Cruz, C.M., Halda-Alija, L., Louws, F.J., Skinner, D.Z., George, M.L., Nelson, R.J., de Bruijn, F.J., Rice, C.W., and Leach, J.E. 1995. Repetitive sequence-based polymerase chain reaction of Xanthomonas oryzae pv. oryzae and Pseudomonas species. International Rice Research Note 20: 23-24.
  23. Yuan, W.Q. 1990. Culture medium for Xanthomonas campestris pv. oryzae. Journal of Applied Bacteriology 69: 798-805.
  24. Zhao, W.J., Zhu, S.F., Liao, X.L., Chen, H.Y., and Tan, T.W. 2007. Detection of Xanthomonas oryzae pv. oryzae in seeds using a specific Taqman probe. Molecular Biotechnology 36: 119-127.

If you are unable to find a reference, contact STCAPS@usda.gov. See the CAPS Pest Datasheet for all references.