International Symposium on Cereal Leaf Blights 2019 | University College Dublin, Ireland | 22-24 May 2019

REVISITING THE BASICS AND THE MULTIPLE RESISTANCE CONCEPT


Fernanda M. Gamba*
Departamento de Protección Vegetal, Facultad de Agronomía, Estación Experimental “Dr. M. A. Cassinoni”, Ruta 3 k 363, CP 60.000, Paysandú, Uruguay

Stephen E. Strelkov
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada

Amor Yahyaoui
Wheat-CRP Septoria Phenotyping Platform Regional Field Crop Research Center of Beja (CRRGC) BP 350, 9000 Beja, Tunisia


Oral Presentation
Cultural Management, Fungicide Resistance and Epidemiology

Moore Auditorium, UCD O'Brien centre for Science
22 May 2019, 15:00

View this abstract online by visting isclb2019.com/see/ABS20341

Diverse genetic resistance is the most effective and environmental friendly measure to manage any disease, therefore, multiple resistance is an obvious approach to prevent/reduce any possible genetic vulnerability in wheat. Pyrenophora tritici-repentis (PTR); Zymoseptoria tritici (STB); yellow and leaf rust frequently occur together and thereby present important resistance breeding targets. STB exhibits differential pathogenicity towards durum and bread wheat and also is highly variable genetically, suggesting that most resistance genes will be short-lived and a continual need to identify new strategiesfor effective disease management. Quantitative virulence in STB matches the quantitative nature of resistance observed in the host, but qualitative gene-for-gene interactions have also been reported for specific isolate–cultivar combinations. Resistance to STB is mainly quantitative, with 13 resistance genes identified and mapped to date, although the function of most of these genes is, as yet, unknown. Eight races of PTR are defined by their ability or inability to induce distinct symptoms (necrosis/chlorosis) caused by necrotrophic effectors (host-selective toxins), with ‘basic’ races producing only a single toxin and ‘composite’ races producing multiple toxins. Three dominant and independently inherited genes were shown to control sensitivity to each of the host-selective toxins, with one gene for each toxin. Although biotechnological approaches have muchpotential and will be very useful in specific situations,particularly in genetic analyses in the laboratory, they probably will be of less use in classical plant breeding programs due to the cost and complexity of the assays. This again brings us back to the basics: accurate phenotypic scoring of host reactions is still the most time-consuming and difficult part of the process, yet it is essential forfuture progress.