Location: Sugarbeet and Bean ResearchTitle: Molecular markers for improving control of soil-borne pathogen Fusarium oxysporum in sugar beet
|DE LUCCHI, CHIARA - University Of Padua|
|STEVANATO, PIERGIORGIO - University Of Padua|
|DE BIAGGI, MARCO - Retired Non ARS Employee|
|BROCCANELLO, C - University Of Padua|
|BERTAGGIA, MARCO - University Of Padua|
|SELLA, LUCA - University Of Padua|
|CONCHERI, GUISEPPE - University Of Padua|
Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2017
Publication Date: 3/1/2017
Citation: De Lucchi, C., Stevanato, P., Hanson, L.E., McGrath, J.M., Panella, L.W., De Biaggi, M., Broccanello, C., Bertaggia, M., Sella, L., Concheri, G. 2017. Molecular markers for improving control of soil-borne pathogen Fusarium oxysporum in sugar beet. Euphytica. 213:71.
Interpretive Summary: Fusarium oxysporum is an important pathogen of sugar beet throughout the world. It causes yellowing and loss of leaves, wilting, and in some cases death of plants. The most widely used and effective method of managing the disease, Fusarium yellows, is by host resistance. Material with resistance has been identified in the United States, but there has been little screening of material from other areas. In the current study 29 sugar beet parental lines from an Italian breeding program were tested for response to F. oxysporum. The two isolates tested both caused disease, but one caused more severe disease than the other. The lines tested varied in their responses. Three lines had high disease ratings and more than 80% of the plants died with the more aggressive pathogen strain. Three lines were identified that had low disease severity values that were not different from the known resistant controls. It was noted that several roots from the susceptible lines showed a root rot symptom that is not typically observed when plants are infected with this pathogen in the United States. This was the first test for Fusarium oxysporum resistance in an Italian sugar beet germplasm. Using this method, lines were successfully identified with high tolerance. Use of the sources of tolerance may expand the material available for resistance breeding and can contribute to improved Fusarium tolerance in sugar beet.
Technical Abstract: Fusarium oxysporum f. sp. betae (FOB) is an important pathogen of sugar beet worldwide causing leaf yellowing and vascular discoloration. The use of tolerant varieties is one of the most effective methods for managing this disease. In this study, a large germplasm collection,comprised of 29 sugar beet parental lines, was tested for FOB tolerance under greenhouse conditions. Five-week-old sugar beet plants were inoculated using a root dip method with two highly virulent isolates of FOB, F19 and Fob220a. Symptom severity was scored using the percentage of dead plants and a 0–5 rating scale for six weeks and the area under disease progress curve (AUDPC) was used to estimate disease development. Both isolates were virulent, but plants inoculated with F19 showed a significantly higher AUDPC mean (p<0.05) as compared to plants inoculated with Fob220a. The evaluated lines showed a varying tolerance response, from extremely susceptible to highly tolerant. Lines 6, 9 and 12 showed high AUDPC values with more than 80% of the plants inoculated with F19 dying during the experiment. Lines A2, A3 and A4 showed very low AUDPC values that were not significantly different from the resistant controls, line 20 and line 7927-4-309. Several roots from susceptible lines showed internal discoloration as well as root rot, even though they were inoculated with Fusarium oxysporum f. sp. betae. This first screening for Fusarium oxysporum resistance on an Italian sugar beet germplasm led to identification of highly tolerant genotypes. Incorporation of these sources of tolerance to a breeding program will contribute to improve Fusarium tolerance in sugar beet.