Comparison of two different experimental environments for resistance screenings for leafhopper-transmitted wheat dwarf virus in wheat

Abstract

Abstract Wheat dwarf virus (WDV) causes high yield losses in wheat and other cereals and is therefore an important pathogen transmitted by the leafhopper Psammotettix alienus. Symptoms of WDV infection in wheat include dwarfing and high yield losses. Climate change will increase infestations by insect-transmitted viruses due to the increasing spread of vectors. In the context of integrated pest management, the cultivation of WDV-resistant/tolerant varieties is an effective way of controlling WDV. Evaluation of tolerant/resistant genotypes is based on inoculation with virus-bearing leafhoppers and subsequent phenotyping in gauze houses under semi-field conditions. For successful screening, it is important to ensure a uniform and reproducible inoculation of plants. Abiotic conditions, particularly temperature, have a critical influence on inoculation success, and thus variations in infection rates were observed within and between previous replicates in the field. Furthermore, the leafhopper population reared in the greenhouse had to be reestablished after each infection, which delayed the screening process. We addressed these issues by developing an improved inoculation assay in which plants are inoculated in small infection hoods in the greenhouse before being planted out in gauze houses. This procedure allows optimal environmental conditions for WDV infection of test plants and allows the plants with WDV infection to develop under natural environmental conditions, such as for symptom scoring. In addition, the virus-bearing leafhoppers were re-collected from the test plants after infection, allowing economically sustainable use of the animals. The method thus enables more reliable phenotyping by increasing infection success and testing a greater number of genotypes in a shorter time.