A complete physical map of a wild beet (Beta procumbens) translocation in sugar beet

Abstract

Two sugar beet lines carry homologous translocations of the wild beet Beta procumbens. Long-range restriction mapping with rare cutting enzymes revealed that both translocations are different in size, however, an overlapping region of about 350 kb could be identified. Both lines are resistant to the beet cyst nematode but only TR520 carries the previously cloned resistance gene Hs1pro-1. Hence, a second gene for nematode resistance (Hs1-1) must be located within this region. A bacterial artificial chromosome (BAC) library was constructed from line TR520. The library was screened with a number of B. procumbens specific probes and 61 BAC clones were identified. Five BAC clones formed a minimal tiling path of 580 kb to cover the overlapping region between both translocations including the translocation breakpoint. The five BACs from the overlapping region and one additional BAC distal from that contig were sequenced. The total sequence length from the five BACs of the overlapping region amounted to 524 kb which is 74.35% of the total insert size of these BACs. The frequency of retrotransposon sequences ranged between 14.7 and 43.3%. A total of 133 ORFs were identified, none of these showed similarity to known disease resistance genes. Of these, 12 ORFs showed homology to genes involved in biotic stress resistance reactions or to transcription factors. This paper demonstrates how genome specific probes can be employed for cloning an alien gene introgression into a cultivated species.

Conservation and divergence of autonomous pathway genes in the flowering regulatory network of Beta vulgaris

“…EST sequence information was used to generate genomic fragments for use as probes to screen the B. vulgaris BAC library described by Schulte et al (2006). Probe fragments were generated by PCR amplification using primer combinations A039–A064 for BvFLK (717 bp), A066–A042 for BvFVE1 (1089 bp), A043–A067 for BvLD (589 bp), and A033–A065 for BvLDL1 (678 bp), and genomic DNA of A906001 as template, and purified using the Montage PCR 96 Cleanup Kit (Millipore Corporation, Bedford, CA, USA).…”

Conserved Microsynteny ofNPR1with Genes Encoding a Signal Calmodulin-Binding Protein and a CK1-Class Protein Kinase inBeta vulgarisand Two Other Eudicots

“…An integrase gene has four exons and, from amino acid positions 750 to 900, this ORF encodes an rve core domain ( E = 3e −30 ), being a characteristic of integrases. With the integrase gene and the downstream putative gene Hp3 being combined, both share about 98% nucleotide identity (BLASTN) with highly related genes on a 9 Kb DNA contig (GenBank accession ABD83280) of BAC62 from sugarbeet chromosome 9 [26]. A putative reverse transcriptase gene about 5 Kb downstream of Hp3 consists of a single exon encoding a polyprotein with Rvt2 RNA-dependent DNA polymerase domain ( E = 7e −24 ), an rve integrase domain ( E = 6e −21 ), and a poorly conserved ( E = 8e −10 ) gag capsid-like protein domain.…”

Plant Nematode Control

“…In Arabidopsis, which is also a host for H. schachtii, a series of sequence homologues of Hs1 pro-1 have been detected, but none of these confers resistance and only the wild beet Hs1 pro-1 variant was able to efficiently protect Arabidopsis upon transformation (Zhang et al 2008;Cai et al 2005). However, as no complete resistance could be observed by transgenic sugar beet plants so far (Cai, unpublished data), it is proposed that a second gene may be involved in the resistance expression (Schulte et al 2006). A putative cation transporter gene linked to Hs1 pro-1 (Oberschmidt et al 2003) and a gene encoding a protein with homology to phosphatidylinositol-specific phospholipase X-box domain as well as germin-like proteins have been isolated nematode-resistant sugar beet by transcriptional analysis (Samuelian et al 2004;Knecht et al 2010).…”