Maize (Zea mays) is a species that originates from Central America with exceptional morphological and molecular diversity. Breeders have selected and recombined this diversity for more than 7000 years and commercial hybrid breeding has ensued for a century. Therefore, it serves as model species widely used for genetic studies and is the first model plant after Arabidopsis thaliana.
Zea mays is therefore used in our institute for quantitative studies: for genetic diversity (Horn et al. 2013; Van Inghelandt et al. 2010), linkage disequilibrium (Van Inghelandt et al. 2011), quantitative trait loci detection (Frey et al. 2016, Horn et al. 2015), expression and transcription studies (Urbany et al. 2013; Frey et al. 2015), association mapping (Stich and Gebhardt 2011; Van Inghelandt et al. 2012), genome-wide prediction, and selection (Benke et al. 2015; Van Inghelandt et al. 2019 in review).
- Resistance gene to BYDV in maize
Project: Identification and characterization of a resistance gene against Barley Yellow Dwarf Virus in maize
Barley yellow dwarf is the most widely spread viral disease of cereals. It is caused by the Barley yellow dwarf virus (BYDV) and the Cereal yellow dwarf virus (CYDV), where the first is causing more severe damages than the second. Maize plays an important role in the epidemiology of BYDV and is as well damaged by the virus. With increasing global temperatures, viral diseases in general and BYDV in specific are expected to become prominent problems in cereal and maize cultivation. The control of the virus itself is not possible. The BYDV-transmitting aphids (e.g. Rhopalosiphum padi) feed on various cereals and other grass species and can be controlled by insecticides. Resistant maize can break the transmission cycle of BYDV and therewith could as well contribute to a reduction of the BYDV problems in other cereals. In an earlier study, we detected a BYDV resistance factor at the bottom of chromosome ten, which explained considerable proportions of the phenotypic variance of the traits virus concentration and disease symptoms. Based on these experiments, the gene GRMZM2G018027 is the best candidate as BYDV resistance gene. The homolog of this gene in Arabidopsis thaliana is OXS3 that is described to be involved in the production of H2O2. As H2O2 is known to play an important role in pathogen defense, GRMZM2G018027 could be involved in a general pathogen defense reaction.
One of the objectives of the project is to identify and validate the BYDV resistance gene in maize. This will be reached with the help of five so-called heterogeneous inbred families. Artificial inoculation experiments and experiments characterizing the sucking behaviour of aphids on parent inbred lines and recombinant plants of the heterogeneous inbred families as well as genotypes that were created by transforming the maize inbred A188 with different alleles of GRMZM2G018027 are used to improve our understanding of the function of the BYDV resistance gene. Additionally, molecular, biochemical and histological techniques are applied. Furthermore, we plan to quantify the contribution of the BYDV resistance gene to variation of other viral diseases.
To reduce greenhouse gas from finite fossil fuels, effort are needed to replace them with sustainable, carbon-neutral resources. Agricultural residues from crops could be one alternative. The majority of agricultural residues consists of so called lignocellulosics, a composite of non-food plant material. The biggest challenge in converting lignocellulosics to usable chemicals is overcoming the material’s recalcitrance to degradation.
The research project CORNWALL identified and continues to identify non-transgenic, economically competitive maize mutants/varieties that upon whole plant processing result in altered yields of sugar derived from their lignocellulosic biomass. In the frame of this project, more than 700 maize landraces from gene banks will be phenotyped and genotyped/sequenced to find genetic factors underlying the degradation of lignocellulosics. The results of this project will help to improve resource efficiency and set the stage for an improved material-industrial use of the maize plant.