Reaction of Indicator Tobacco Cultivars to Races of Pseudomonas syringaepv. tabaciTox+

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Abstract

Three races of Pseudomonas syringaepv. tabaciTox+ (wildfire) (races 0, 1 and 2) and two races of Tox- (angular leaf spot) (races 1 and 2) have been confirmed on tobacco in Zimbabwe (Zim). Very few cultivars with no resistance to Ps. syringaepv. tabaci are grown commercially and race 0 has not been isolated since 1996. Because we no longer have a viable culture of race 0, we obtained an isolate of race 0 from Kentucky (0 KY), USA in January 2000. We included this isolate in race tests on standard indicator cultivars K E1 (susceptible to all races), KM 10 (resistance to race 0 derived from Nicotianalongiflora), WZ (resistance to races 0 and 1 derived from N. rustica) and a hybrid, K 35 (resistance to races 0 and 0 and 1 derived from N. longiflora and N. rustica respectively). Two leaves on 10-week-old seedlings were inoculated with a bacterial suspension (106 colony forming units [cfu] per mL) by spraying selected areas until just watersoaked and incubating the plants at 28 C and 70% RH for 10 d. The reaction to race 0, measured as lesion diameter, was different from that previously obtained with race 0 (Zim). Races 0 and 1 (Zim) are avirulent on WZ but race 0 (KY) was virulent. Further isolates of race 0 were received from Maryland (MD) and Tennessee (TN). The TN isolates overcame resistance derived from N. longiflora and N. rustica, except where both sets of genes were present in the same cultivar. Reactions have been variable with the race 0 (MD) isolate suggesting it is a mixed culture. We conclude that there are at least four races of Ps. syringaepv. tabaciTox+ worldwide and race 0 (KY) should be designated race 3. On all cultivars, race 2 consistently caused the largest lesions.

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  • 1. Cole D.L.: The efficacy of acibenzolar-S-methyl an inducer of systemie acquired resistance against bacterial and fungal diseases of tobacco; Crop Protect. 18 (1999) 267K273.

  • 2. Cole D.L.: Seedbed disease management; Zimbabwe Tob. 9 (2000) 11.

  • 3. Clayton E.E.: A wildfire resistant tobacco; J. Hered. 38 (1948) 35K40.

  • 4. Stokes G.W.: Difference in the behavior of the Nicotiana longiflora wildfire resistance locus to tobacco varieties Burley 21 and KY 61; Phyto-pathology 50 (1960) 770K772.

  • 5. Smeeton B.W. and R.A.F. Ternouth: Sources of resistance to powdery mildew wildfire angular leaf spot and alternaria; Information Buli. CORESTA no. 3K4 (1992) 127K135.

  • 6. Woodend J.J. and E. Mudzengerere: Inheritance of resistance to wildfire and angular leaf spot deriyed from Nicotiana rustica var. Brasilea; Euphytica 64 (1992) 149K156.

  • 7. Stavely J.R. and H.A. Skoog: Stabilization in Nicotiana tabacum of a dominant gene from N. rustica for resistance to a virulent strain of Pseudomonas tabaci; Phytopathol. News 12 (1978) 181 Abstract.

  • 8. Mapuranga N.: A new race of Pseudomonas synn-gae pv. tabaci on tobacco in Zimbabwe; Plant Dis-ease 82 (1998) 1404.

  • 9. Chibi N.: Pathogenicity and race determination of Pseudomonas synngae pv. tabaci (wildfire and angular leaf spot forms) including resistance testing in transgenic tobacco plants; MSc thesis Department of Crop Science University of Zimbabwe 1992.

  • 10. Deall M.W. and J.S. Cole: A comparative study of the pathogenicity and epidemiology of strains of Pseudomonas synngae pv. tabaci that cause wildfire and angular leaf spot diseases of tobacco in Zimbabwe; Plant Pathol. 35 (1986) 74K81.

  • 11. King E.O. M.K. Ward and D.E. Raney: Two simple media for the demonstration of pyocyanin and fluorescein; J. Lab. Clin. Med. 44 (1954) 301K307.

  • 12. Stavely J.R.: Disease resistance pg 87-110; im Nicotiana: Procedures for experimental use edited by R.D. Durbin U.S. Department of Agriculture Technical Bulletin (1979) 1586.

  • 13. Cole J.S. and J.G. Raeber: New virulent strains of Pseudomonas tabaci able to infect Burley 21 and TL106 tobacco varieties; 2”d International Congress of Plant Pathology University of Minnesota ISSP in collaboration with APS and Society of Nematologists 1973 Abstract.

  • 14. Knoche K.K M.K. Clayton and R/W. Fulton: Comparison of resistance in tobacco to Pseudomonas synngae pv. tabaci races 0 and 1 by infectivity titrations and bacterial multiplication; Phyto-pathology 77 (1987) 1364K1368.

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