Characterization of recombinants of the Aegilops peregrina-derived Lr59 translocation of common wheat

Abstract

A compensating, recombined Lr59 translocation with greatly reduced alien chromatin was identified. Microsatellite locus Xdupw217 occurs within the remaining segment and can be used as a co-dominant marker for Lr59. In earlier studies, leaf rust (caused by Puccinia triticina Eriks.) resistance gene Lr59 was transferred from Aegilops peregrina (Hackel) Maire et Weiler to chromosome arm 1AL of common wheat (Triticum aestivum L.). The resistance gene was then genetically mapped on the translocated chromosome segment following homoeologous pairing induction. Eight recombinants that retained the least alien chromatin apparently resulted from crossover within a terminal region of the translocation that was structurally different from 1AL. These recombinants could not be differentiated by size, and it was not clear whether they were compensating in nature. The present study determined that the distal part of the original translocation has group 6 chromosome homoeology and a 6BS telomere (with the constitution of the full translocation chromosome being 1AS·1L(P)·6S(P) ·6BS). During the allosyndetic pairing induction experiment to map and shorten the full size translocation, a low frequency of quadrivalents involving 1A, the 1A translocation, and two 6B chromosomes was likely formed. Crossover within such quadrivalents apparently produced comparatively small compensating alien chromatin inserts within the 6BS satellite region on chromosome 6B of seven of the eight recombinants. It appears that the Gli-B2 storage protein locus on 6BS has not been affected by the recombination events, and the translocations are therefore not expected to affect baking quality. Simple sequence repeat marker results showed that Lr59-151 is the shortest recombinant, and it will therefore be used in breeding. Marker DUPW217 detects a homoeo-allele within the remaining alien chromatin that can be used for marker-assisted selection of Lr59.

Mapping of Lr56 translocation recombinants in wheat

“…peregrina that occurs at the 6BS telomeric region of the Lr59 ‐151 translocation (Pirseyedi et al. ). Thus, Lr56 and Lr59 could be homoeoloci.…”

“…Wheat SSR primer pair Dupw217 detects a marker locus at the short arm telomere end of certain homoeologous group 6 chromosomes (Pirseyedi et al. , Sourdille et al. ).…”

“…, Pirseyedi et al. ) were tested for the presence of the Xdupw217 marker locus. Prior to the analyses, translocation homozygotes were identified with respect to each full‐length or recombined translocation by progeny testing of seedlings with P. triticina pathotypes MFPS or TDBG.…”

Registration of Spring Wheat Sources of Leaf Rust Resistance Genes Lr53, Lr56, Lr59, and Lr62

“…The Dupw217 primer sequences and polymerase chain reaction (PCR) conditions were obtained from GrainGenes (2002). Lyophilized seedling leaves were used for DNA extraction following a modified Doyle and Doyle (1990) protocol described by Diversity Arrays Technology (nd), and PCR reactions were performed as outlined by Pirseyedi et al (2015). The PCR products were separated in 3 to 4% (w/v) AMRESCO Agarose SFRTM agarose gel, treated with ethidium bromide and visualized using a ProteinSimple AlphaImager HP System.…”

Targeted Segment Transfer from Rye Chromosome 2R to Wheat Chromosomes 2A, 2B, and 7B

“…Various alien genes offering resistance yield and other beneficial traits have been transferred into bread wheat through the induction of translocation of alien chromosomes from a closely related genera [Mettin et al, 1973;Zeller, 1973;Sears, 1981;Ren et al, 1990aRen et al, , b, 2012Chen et al, 1995;Fu et al, 2014;Tang X et al, 2014;Pirseyedi et al, 2015;Zhang et al, 2015;Dai et al, 2016;Kuzmanovi et al, 2016]. These translocations integrate an entire arm of an alien chromosome, which may contain adverse chromatin along with the desired genes, thereby limiting the application of the alien translocation lines in wheat improvement.…”