Inheritance of resistance to beet necrotic yellow vein virus in Beta vulgaris conferred by a second gene for resistance

Abstract

Rhizomania is a serious disease of sugar beet, caused by beet necrotic yellow vein virus (BNYVV). The disease can only be controlled by the use of resistant cultivars. The accession Holly contains a single dominant gene for resistance, called Rz. The identification of a locus for resistance that differs from Rz would provide possibilities to produce cultivars with multiple resistance to BNYVV. Inheritance of resistance to BNYVV was studied by screening progenies of crosses between resistant plants of the accessions Beta vulgaris subsp. maritima WB42 and B. vulgaris subsp. vulgaris Holly-1-4 or R104. Observed and expected segregation ratios were compared to elucidate whether the resistance genes in the three accessions are alleles or situated on different loci. STS markers, linked to the genes for resistance, were used to study the segregation in more detail. The results demonstrated that the genes for resistance to BNYVV inHolly-1-4 and WB42 are closely linked. The gene for resistance in R104 is at the same locus as in Holly-1-4, and also closely linked to the gene in WB42. As the Holly resistance gene has been named Rz, the name Rz2 is proposed to refer to the resistance gene in WB42. Consequently, the gene Rz should be referred to as Rz1.

A new RAPD marker for beet necrotic yellow vein virus resistance gene in Beta vulgaris

“…Although, Scholten et al (1999) obtained three distance maxima of 20, 40, and 38 cM between Rz 1 and Rz 2 from two different generations (20 and 40 cM from a backcross generation and 38 cM from an F 2 generation). In some generations not included in the results and conclusions of the study, Rz 1 and Rz 2 genes were unlinked.…”

“…The distance of the nearest marker from Rz 2 was 0.036 rf (Table 3). Regarding the linkage of the resistance loci in WB42 and Holly-1-4 (Scholten et al 1999, Amiri et al 2003a, 2003b, the approximate distance of Rz 2 and Rz 1 were estimated to be 0.464 rf. On this basis, the RAPD markers linked to the resistance gene(s) in WB42 and Holly-1-4 were used to construct a short map around the resistance loci (Fig.…”

Evaluation of rhizomania-resistance segregating sequences and overall genetic diversity pattern among selected accessions of Beta and Patellifolia. Potential implications of breeding for genetic bottlenecks in terms of rhizomania resistance

“…What is more, a hypothesis of different resistance sources have been raised, but at the same time it is not fully consistent yet, at least in some cases, whether they are conditioned by independent loci or by genes that represent in fact an allelic series. For example, over the course of the experimental crosses between Rz1-and Rz2-carrying materials (Holly-1-4 and WB42) it was determined that the distance between these genes may be as high as 20 to 35 cM (Scholten et al 1999;Amiri et al 2003), however the distinction between these genes and closely located Rz3 identified in WB41 may not be so unequivocal (Gidner et al 2005). On the other hand, the situation seems to be more complex, as there are reports suggesting the presence of further genes, such as Rz4 and Rz5 (Grimmer et al 2007(Grimmer et al , 2008.…”

Genome Analysis: Mapping in Sugar Beet

“…Location of genes for Mendelian traits and quantitatively inherited characters (QTL) on the nine chromosomes of sugar beet. The chromosomes were designated as suggested by Butterfass (1963) and PsbO, cTRF, PsaL, PsbR, PetH, PsbP, PsaE, PsbQ, PsaH, PetC (Pillen et al 1996) d Butterfass (1963) e Keller (1936); Owen et al (1940); Owen and Ryser (1942) f Early bolting B (Boudry et al 1994) g Root color Y, curly top resistance C, cited from (Wagner et al 1992) h Stem fasciation Fas, restoration of male fertility Z and X, and more isozyme loci (Wagner et al 1992) i Nematode resistance gene Nema (Uphoff and Wricke 1995) j Pillen et al (1993) k Resistance to rhizomania, Rr1, monogerm character M (Barzen et al 1995) l Skdh2 might be linked with a restorer gene, perhaps X (Abe et al 1993) m Z might be linked with M (Roundy and Theurer 1974) n Late bolting, Nb, sugar content, Sc (Savitsky 1958) o Laporte et al (1998) Weber et al (2000) t Setiawan et al (2000) u Schäfer-Pregl et al (1999) v Scholten et al (1999) w Hjerdin-Panagopoulos et al (2002) x Schneider et al (2002) cence were processed, resulting in the identification of 30,444 clusters (Herwig et al 2002). After sequencing 10,961 clones, 9745 different cDNAs were identified.…”

“…Both genes are located on the same chromosome at a distance of 20 cM. Rz2 was mapped with STS markers linked at a distance between 2 and 11 cM (Scholten et al 1999). Two RGA were found to be linked to the Rr1 gene, however, recombination between the resistance and the RGAs ruled out the possibility that the RGAs could represent that gene (Hunger et al 2003).…”