Gpc-B1 gene from Triticum turgidum ssp. dicoccoides. Stripe rust resistance gene Yr36
Gpc-B1 gene from Triticum turgidum ssp. dicoccoides
References
1. Chromosomal location of genes for grain protein content of wild tetraploid wheat. Joppa, L. R.; Cantrell, R. G.; In: Crop Science,1990. 30(5):1059-1064
The improvement of grain-protein content is an important goal of durum wheat (Triticum turgidum L.) and other wheat breeding programs. The objective of this study was to determine the chromosomal location of genes for high grain-protein content in an accession of wild tetraploid (emmer) wheat (T. turgidum L. var. dicoccoides)having seeds with high grain-protein content. The method was to substitute each of the dicoccoides (DIC) chromosomes into 'Langdon' (LDN) durum by crossing and backcrossing with a set of LDN D-genome disomic substitution lines. All of the Langdon-dicoccoides, LDN(DIC), substitution lines were vigorous and fertile except the LDN(DIC-2B), lines, which were low in vigor and partially sterile. The substitution lines for each of the other 13 chromosomes, the 1D(1A), 4D(4B), and 7D(7A) D-genome disomic substitutions, and the cultivars LDN, Ward, Monroe, and Vic were grown in field experiments with four replicates at two locations in each of two years and were evaluated for grain-protein content. The following lines had significantly higher grain-protein content that LDN: LDN(DIC-6B) > LDN(DIC-2A) > LDN(DIC-5B) = LDN(DIC3A) = LDN(DIC-6A). Lines with significantly less grain protein than the recurrent parent LDN were LDN(DIC-3B), LDN(DIC-4B), and LDN(DIC-7B). The high grain-protein content of the LDN(DIC-2A) lines may have been related to their low grain yield. The consistently high grain-protein content of the LDN(DIC-6B) lines suggests that this DIC chromosome has one or more important genes affecting this character. These LDN(DIC) substitution lines should prove useful in breeding improved durum wheat cultivars with increased grain-protein content.
2. Grain protein determinants of the Langdon durum-diccoides chromosome substitution lines. Deckard, E. L.; Joppa, L. R.; Hammond, J. J.; Hareland, G. A. In: Crop Science, 1996. 36(6):1513-1516.
High grain protein content of durum wheat (Triticum turgidum L.) is important for improved cooking and nutritional quality. The development of a set of 'Langdon'-dicoccoides (LDN(DIC)) chromosome substitution lines offers an opportunity to develop new high protein durum cultivars. The objective of this research was to determine under field conditions the biological reason for the changes in grain protein content. The substitution lines studied included two LDN(DIC-2A) lines; one each of the LDN(DIC-4A), LDN(DIC-4B), and LDN(DIC-5B) lines; and three LDN(DIC-6B) lines. The changes in accumulation and partitioning of dry weight (DW) and N as a result of substituting specific DIC chromosomes into LDN durum were consistent across the environments tested. Certain DIC chromosomes altered the accumulation ratio (total plant N/total plant DW), others altered the partitioning ratio (N harvest index/harvest index), and others appeared to alter both ratios to affect grain protein content. The major reason for the lower N contents of the 2A, 4A, and 4B lines was a decreased partitioning ratio, and the major reason for the higher N content of the 5B line was a higher accumulation ratio. The 6B lines were the only lines where the accumulation and partitioning ratios were always equal to or greater than LDN. The three 6B lines varied for the relative importance of changes in the accumulation and partitioning ratios to increase grain N content.
3. Mapping gene(s) for grain protein in tetraploid wheat (Triticum turgidum L.) using a population of recombinant inbred chromosome lines. Joppa, L. R.; Du, C.; Hart, G. E.; Hareland, G. A. In:Crop Science, 1997. 37(5):1586-1589
A 'Langdon' durum wheat line with a pair of 6B chromosomes from an accession of Triticum turgidum L. var. dicoccoides (Korn. in litt., in Schweinf.) Bowden (LDN(DIC-6B)) previously was shown to have a gene(s) for high grain protein content (GPC). The objectives of this study were to develop a mapping population segregating only for genes on chromosome 6B, map the gene(s) for high GPC, and identify closely linked markers for use in marker-assisted breeding for this trait. The 6B mapping population was grown in replicated field trials and evaluated for GPC. A restriction fragment length polymorphism (RFLP) map of this population was available. The quantitative trait locus (QTL) analyses provided strong evidence that a genets) for high GPC (named QGpc.ndsu-6Bb) is located near the centromere of 6B. The most likely location for the gene(s) is in the short arm between Xabg387-6B and Xmwg79-6B. The logarithm of the odds (LOD) score for this interval is 18.9. Segregation in this segment accounted for 66% of the variation in GPC. Eleven additional markers have been mapped within 7 centimorgans (cM) of the midpoint of Xabg387-6B and Xmwg79-6B. One or more of these markers should be useful in marker-assisted breeding for high GPC in durum wheat.
4. Quality characteristics of durum wheat lines deriving high protein from a Triticum dicoccoides (6b) substitution.Kovacs, M. I. P.; Howes, N. K.; Clarke, J. M.; Leisle, D. In: Journal of Cereal Science, 1998. 27(1):47-51
One of the objectives in the Canadian durum wheat (Triticum turgidum L.) breeding programs has been the selection of lines having higher protein content. The Langdon-dicoccoides (Triticum dicoccoides 6B) substitution, a source of high protein, has been introgressed into two high yielding, but lower protein Canadian lines of durum wheat. The resulting lines with protein content similar to registered cultivars were evaluated for protein quality. The introgression had no detrimental effects upon pasta cooking quality, and thus the dicoccoides 6B chromosome substitution will be a valuable route to increasing protein level for the durum wheat breeding program.
5. RFLP markers associated with high grain protein from Triticum turgidum L. var. dicoccoides introgressed into hard red spring wheat. Mesfin, A.; Frohberg, R. C.; Anderson, J. A.; In:Crop Science, 1999. 39(2):508-513.
Increased grain protein is desirable for many bread and pasta products. Because of its importance to end-use quality and human nutrition, this trait has been widely studied. This study was conducted to (i) identify genomic regions associated with high grain protein concentration (GPC) inherited from Triticum turgidum L. var. dicoccoides in three hard red spring wheat recombinant inbred (RI) populations (ND683/'Bergen', 'Glupro'/'Keene', and Glupro/Bergen); (ii) examine the effects of genetic background and environment on these genes; and (iii) determine the genetic size of the Triticum turgidum L. var. dicoccoides chromosomal segment introgressed into hard red spring wheat genotypes. The F5-derived RI lines were grown at five environments for the ND683/Bergen population and at three environments for the other two populations. The range of GPC in the ND683/Bergen, Glupro/Keene, and Glupro/Bergen population was 142 to 179, 149 to 182, and 139 to 183 g kg-1, respectively. The four parental genotypes were surveyed for polymorphisms with 96 low copy DNA clones located on group 5 and 6 chromosomes. A single region associated with high GPC was detected with five RFLP markers (Xcdo365, Xmwg79, Xbcd102, Xbcd357, and Xcdo1380) located near the centromere on chromosome 6B. One of the markers (Xcdo365) identified a 6.5-kb restriction fragment in Triticum turgidum var. L. dicoccoides, Glupro, ND645, and ND683. Hence, this fragment is in coupling linkage to high GPC gene(s). This marker explained 21 to 35% of the phenotypic variation in GPC in the three populations. The DNA marker in this region might be used to rapidly introgress this gene for high GPC into other wheat germplasm.
6. Development of PCR-based markers for a high grain protein content gene from Triticum turgidum ssp. dicoccoides transferred to bread wheat. Khan IA, Procunier JD, Humphreys DG, Tranquilli G, Schlatter AR, Marcucci-Poltri S, Frohberg R, Dubcovsky J. In: Crop Science, 2000, 40(2):518-524.
The conservation of the linear order (colinearity) of genetic markers along large chromosome segments in wheat and rice is well established, but less is known about the microcolinearity between both genomes at subcentimorgan distances. In this study we focused on the microcolinearity between a 2.6-cM interval flanked by markers Xcdo365 and Xucw65 on wheat chromosome 6B and rice chromosome 2. A previous study has shown that this wheat segment includes the Gpc-6B1 locus, which is responsible for large differences in grain protein content (GPC) and is the target of a positional cloning effort in our laboratories. Twenty-one recombination events between Xcdo365 and Xucw65 were found in a large segregating population (935 gametes) and used to map 17 genes selected from rice chromosome 2 in the wheat genetic map. We found a high level of colinearity between a 2.1-cM region flanked by loci Xucw75 and Xucw67 on wheat chromosome 6B and a 350-kb uninterrupted sequenced region in rice chromosome arm 2S. Colinearity between these two genomes was extended to the region proximal to Xucw67 (eight colinear RFLP markers), but was interrupted distal to Xucw75 (six non-colinear RFLP markers). Analysis of different comparative studies between rice and wheat suggests that microcolinearity is more frequently disrupted in the distal region of the wheat chromosomes. Fortunately, the region encompassing the Gpc-6B1 locus showed an excellent conservation between the two genomes, facilitating the saturation of the target region of the wheat genetic map with molecular markers. These markers were used to map the Gpc-6B1 locus into a 0.3-cM interval flanked by PCR markers Xucw79 and Xucw71, and to identify five candidate genes within the colinear 64-kb region in rice.
7. Microcolinearity between a 2-cM region encompassing the grain protein content locus Gpc-6B1 on wheat chromosome 6B and a 350-kb region on rice chromosome 2. Distelfeld A, Uauy C, Olmos S, Schlatter AR, Dubcovsky J, Fahima T. In: Functional & Integrative Genomics, 2004, 4: 59-66.
The conservation of the linear order (colinearity) of genetic markers along large chromosome segments in wheat and rice is well established, but less is known about the microcolinearity between both genomes at subcentimorgan distances. In this study we focused on the microcolinearity between a 2.6-cM interval flanked by markers Xcdo365 and Xucw65 on wheat chromosome 6B and rice chromosome 2. A previous study has shown that this wheat segment includes the Gpc-6B1 locus, which is responsible for large differences in grain protein content (GPC) and is the target for a positional cloning effort in our laboratories. Twenty-one recombination events between Xcdo365 and Xucw65 were found in a large segregating population (935 gametes) and used to map 17 genes selected from rice chromosome 2 in the wheat genetic map. We found a high level of colinearity between a 2.1-cM region flanked by loci Xucw75 and Xucw67 on wheat chromosome 6B and a 350-kb uninterrupted sequenced region in rice chromosome arm 2S. Colinearity between these two genomes was extended to the region proximal to Xucw67 (8 colinear RFLP markers), but was interrupted distal to Xucw75 (6 non-colinear RFLP markers). Analysis of different comparative studies between rice and wheat suggests that microcolinearity is more frequently disrupted in the distal region of the wheat chromosomes. Fortunately, the region encompassing the Gpc-6B1 locus showed an excellent conservation between the two genomes, facilitating the saturation of the target region of the wheat genetic map with molecular markers. These markers were used to map the Gpc-6B1 locus into a 0.3-cM interval flanked by PCR markers Xucw79 and Xucw71, and to identify five candidate genes within the colinear 64-kb region in rice.
8. Physical map of the wheat high-grain protein content gene Gpc-B1 and development of a high-throughput molecular marker. Distelfeld A, Uauy C, Fahima T, Dubcovsky J. In: New Phytologist, 2006, 169:753-763
Grain protein content (GPC) is important for human nutrition and has a strong influence on pasta and bread quality. A quantitative trait locus, derived from a Triticum turgidum ssp. dicoccoides accession (DIC), with an average increase in GPC of 14 g/kg was mapped on chromosome 6BS.
Using the wheat-rice colinearity, a high-density map of the wheat region was developed and the quantitative trait locus was mapped as a simple Mendelian locus designated Gpc-B1. A physical map of approx. 250 kb of the Gpc-B1 region was developed using a tetraploid wheat bacterial artificial chromosome library.
The constructed physical map included the two Gpc-B1 flanking markers and one potential candidate gene from the colinear rice region completely linked to Gpc-B1. The relationship between physical and genetic distances and the feasibility of isolating genes by positional cloning in wheat are discussed.
A high-throughput codominant marker, Xuhw89, was developed. A 4-bp deletion present in the DIC allele was absent in a collection of 117 cultivated tetraploid and hexaploid wheat germplasm, suggesting that this marker will be useful to incorporate the high GPC allele from the DIC accession studied here into commercial wheat varieties.