ABSTRACT
Microsatellite markers were used for the assessment of genetic diversity and genetic structure in a germplasm collection of yellow mustard, Sinapis alba L. The comprehensive collection of genetic resources represented 187 registered varieties, landraces, and breeding materials. Microsatellites generated 44 polymorphic alleles in 15 loci. Eleven of them were medium to highly polymorphic, and the high levels of observed heterozygosity (0.12-0.83) and Nei's gene diversity index (0.11-0.68) indicated a high level of polymorphism. Based on PCoA and neighbor joining analyses, the genetic resources were divided into two groups. The range of genetic dissimilarity in the analysed collection was in the range of 0.00-1.00. The high level of dissimilarity between the accessions was documented by the high WAM value (33.82%). Bayesian clustering algorithms were performed in the STRUCTURE 2.3.4 software. The number of clusters was estimated at K = 2. The accessions were classified according to Q1/Q2 values. The low average values of the parameters Fst_1 (0.3482), Fst_2 (0.1916), and parameter alpha (0.0602) indicated substantial mating barriers between varieties and reproductive isolation due to the limited exchange of genetic resources between breeders. These results demonstrated the importance of extensive collections of genetic resources for the maintenance of genetic diversity and indicated considerable genetic differentiation among accessions.
ABSTRACT
Turnip yellows virus (TuYV), is one of the most important pathogens of oilseed rape, which has caused enormous yield losses in all growing regions of the world in recent years. Therefore, there is a need for resistant varieties for sustainable crop protection. We have investigated the resistance of known varieties and newly developed advanced-breeding lines of oilseed rape to TuYV in greenhouse and field trials. We have analysed the TuYV titre of individual genotypes inoculated with the virus using viruliferous aphids Myzus persicae. The genotypes 'DK Temptation' and 'Rescator' had the lowest and highest virus titres, respectively, and were used as resistant and susceptible models for comparative analyses with other genotypes. In the greenhouse, the best results were obtained with the genotypes 'OP-8143 DH' (2.94 × 105 copies), OP-BN-72 (3.29 × 105 copies), 'Navajo' (3.58 × 105 copies) and 'SG-C 21215' (4.09 × 105 copies), which reached virus titres about 2 times higher than the minimum virus concentration measured in 'DK Temptation' (1.80 × 105 copies). In the field trials, the genotypes 'Navajo' (3.39 × 105 copies), 'OP-8148 DH' (4.44 × 105 copies), 'SG-C 21215' (6.80 × 105 copies) and OP-8480 (7.19 × 105 copies) had the lowest virus titres and reached about 3 times the virus titre of DK Temptation (2.54 × 105 copies). Both trials showed that at least two commercial varieties (e.g., DK Temptation, Navajo) and three advanced breeding lines (e.g., OP-8143 DH, OP-BN-72, SG-C 21215) had low titres of the virus after TuYV infection. This indicates a high level of resistance to TuYV in 'Navajo' or the newly developed breeding lines and the basis of resistance is probably different from R54 (as in 'DK Temptation'). Furthermore, the greenhouse trials together with RT -qPCR-based virus titre analysis could be a cost-effective and efficient method to assess the level of resistance of a given genotype to TuYV infection compared to the field trials. However, further research is needed to identify the underlying mechanisms causing this difference in susceptibility.
ABSTRACT
Water deficiency is one of the most significant abiotic stresses that negatively affects growth and reduces crop yields worldwide. Most research is focused on model plants and/or crops which are most agriculturally important. In this research, drought stress was applied to two drought stress contrasting varieties of Papaver somniferum (the opium poppy), a non-model plant species, during the first week of its germination, which differ in responses to drought stress. After sowing, the poppy seedlings were immediately subjected to drought stress for 7 days. We conducted a large-scale transcriptomic and proteomic analysis for drought stress response. At first, we found that the transcriptomic and proteomic profiles significantly differ. However, the most significant findings are the identification of key genes and proteins with significantly different expressions relating to drought stress, e.g., the heat-shock protein family, dehydration responsive element-binding transcription factors, ubiquitin E3 ligase, and others. In addition, metabolic pathway analysis showed that these genes and proteins were part of several biosynthetic pathways most significantly related to photosynthetic processes, and oxidative stress responses. A future study will focus on a detailed analysis of key genes and the development of selection markers for the determination of drought-resistant varieties and the breeding of new resistant lineages.
