Specific Mapping of Disease Resistance Genes in Tetraploid Cut Roses

Abstract

Control of fungal diseases is a major constraint of cut-rose cultivation in greenhouses and in transportation around the world. Therefore, development of resistant cultivars is a promising way to reduce the use of chemicals required for controlling the diseases. Genetic analyses and breeding for resistance, however, are hampered by the high degree of heterozygosity and the polyploid nature of cultivated roses. Nucleotide-binding site (NBS) profiling of Van der Linden et al. (2004) was used as a tool enabling a more directed way of studying the genetics of resistance to pathogens responsible for diseases such as powdery mildew. NBS profiling is a multiplex screening technique, producing amplified resistance gene (R-gene) and resistance gene analogue (RGA) fragments by using degenerated primers based on the conserved motifs present in the NBS domain of resistance genes. Since RGAs are abundantly distributed and highly polymorphic within the plant genome, NBS profiling generates multiple markers of putative resistance genes. Twelve NBS degenerated primer/ restriction enzyme combinations were used to genotype the whole rose tetraploid K5 population (Yan, 2005) and its parents. To generate RGA profiles, the restriction enzymes: AluI, HaeIII, MseI, and RsaI were used in combination with degenerated primers NBS1, NBS3, and NBS5a6. The profiles were dominantly scored resulting in 106 polymorphic RGA markers which segregated in a 1:1 or 3:1 ratio. Uni-and biparental simplex markers will be mapped on the two available AFLP/SSR K5 maps (Yan, 2005) with Joinmap 4.0. The resulting parental tetraploid maps will be used to dissect the genetic variation for resistance to powdery mildew resistance. Additional Rosaceae SSRs mentioned in the literature are currently tested on the K5 population to obtain allelic bridges between the tetraploid and diploid genetic maps in rose and related species in order to align them. These bridges will improve cross-ploidy comparisons in roses in order to strengthen cut rose breeding.

Towards a unified genetic map for diploid roses

“…Genotyping for this map was done in 170 of the 270 phenotyped progenies. Currently under construction is a map in a tetraploid population in the Netherlands, which is segregating for powdery mildew resistance, based on 184 individuals using NBS markers and SSRs (Koning-Boucoiran et al 2009). Major genes and QTLs for many phenotypic traits have been mapped in all these populations, but these are only useful in the particular genetic background of that speciWc population, even though they are of general interest for rose breeding (see Byrne 2009).…”

Genetic determinism of prickles in rose

“…Using two F1 progenies, Hibrand-Saint Oyant et al (2018) also identified a large QTL (or two neighboring QTLs) on LG3 (between position 31 Mb -46.5 MB corresponding to the end of the chromosome 3) and a significant association between position 31 and 32.4 Mb using a GWAS approach. In tetraploid roses, three QTLs were identified in relation to the number of prickles on the stem: two located on LG2 and one on LG3 (Koning-Boucoiran et al 2009). Using the same K5 population with the same phenotype data but a new genetic map, different QTLs were detected on LG3, 4 and 6 and on LG2 (one year) (Bourke et al 2018).…”

Using aerated compost tea in comparison with a chemical pesticide for controlling rose powdery mildew

“…It is essential to develop a strong workable, compatible package of nutrient management through organic resources for various crops, capable of providing all the essential minerals for promoting growth. Control of fungal diseases is a major constraint of cut-rose cultivation in greenhouses and transportation around the world (Koning-Boucoiran et al 2009). Synthetic fungicides are applied to ornamental crops and many plants to prevent loss of yield and pre-harvest spoilage by fungal pathogens.…”