NordForsk: Climate-ready faba beans for the Nordic and Baltic Region

Work package 1, task 1.1. Prevalence of four causative Botrytis species at different locations and seasons. Chocolate spot in Nordic countries is believed to be caused by up to four different Botrytis species. Sequencing of a set of well characterized nuclear Botrytis genes is commonly used to identify Botrytis species. Another approach to detect and differentiate Botrytis species is to use PCR-assays based on unique species variations at the genetic level. We have established protocols for four different PCR-assays that can be efficiently used to correctly identify B. fabae, B. cinerea, B. pseudocinerea and B. fabiopsis. PCR-assays for the two first species are based on work previously published by others, while the latter two have been developed at NIBIO for the NordForsk project. Their specificity and efficiency have been validated using DNA isolated from a range of different Botrytis species and genotypes. Of importance, all four PCR-assays performed well with DNA isolated from a small collection of infected faba plant samples, suggesting that they can be used for in planta detection of Botrytis. Accordingly, time consuming isolation and cultivation of the pathogen from diseased plant tissue is not required. To further investigate this, we have started to study the prevalence of Botrytis species in Norway using stored infected plant material from 2023. The preliminary results are promising, and the most abundant species seem to be B. fabae and B. cinerea. However, B. pseudocinerea as well as B. fabiopsis have also been detected in some samples. In many cases, several Botrytis species (e.g. B. fabae, B. cinerea and B. pseudocinerea) appear to be present on the same infected plant material. In summary, the testing and optimization of the four PCR-assays are now completed. We have also established a protocol for extraction of Botrytis DNA from infected faba plant material. The resulting DNA usually works fine, but not in all cases. It is currently not clear if this is due to the storage conditions of the infected plant material, or some other factor. As soon as this is figured out, a protocol will be sent out to all involved partners. WP 2 (NMBU): A prelimenary study started Jan 25th, is now early finnished. In this study, we have characterized and compared the fenological development of 15 Faba been lines. The main study will start during spring 2024. It was not started in 2023 as originally planned, due to that we had to wait for propagation of seeds from other partners in the project. WP 3 trials and activities are planned to start in 2025.

Faba bean is a rich source of protein, serving the dietary needs of millions of people and animals. Its production delivers large economic and environmental benefits; as a nitrogen-fixer, little need for nitrogen inputs, helping reduce greenhouse gas emissions. In our region, faba bean gives yields and protein content higher than those of the alternative, pea. However, expansion of its use in our region requires improving yield and yield stability through increased abiotic and biotic stress resistance. We focus on faba bean’s most widespread disease, chocolate spot (caused by different Botrytis species), its most restricting environmental stress, drought, and its most limiting adaptive constraint, growing season length, to identify material with enhanced adaptation and yield potential. We (all partner countries, in Norway: NIBIO) will investigate the relative importance of the different pathogen species in our region, knowledge that is important for disease resistance breeding. We (NIBIO) will start to develop forecasting tools for chocolate spot, enabling farmers to protect their crops. In field experiments, we will test responses to latitude and weather, while dissecting the components of these responses through controlled-environment experiments (all partner countries, in Norway: NMBU). Phenotypic data from these experiments will be combined with genetic and genomic tools and understanding from model systems to identify loci, candidate genes and pathways associated with the desired traits. These will enable allele mining and development of selection tools that breeders can use to accelerate cultivar development. Gene editing will serve to validate candidate genes and to create new allelic diversity. The project will lead to improved faba bean lines and knowledge that can lead to higher and more stable protein yields in our challenging environment, increasing regional protein security and decreasing the pressure for land-use change in soybean-producing countries.