Development and allele diversity of microsatellite markers linked to the aluminium tolerance gene Alp in barley

2003 ◽  
Vol 54 (12) ◽  
pp. 1315 ◽  
Author(s):  
H. Raman ◽  
A. Karakousis ◽  
J. S. Moroni ◽  
R. Raman ◽  
B. J. Read ◽  
...  

Aluminium (Al) toxicity is one of the main factors restricting barley production in acidic soils. The utilisation of barley cultivars tolerant to Al is one of the most economic strategies for expanding barley production in these soils. Among barley genotypes, the cultivar Dayton has been reported to exhibit the highest level of Al tolerance. The gene conferring Al tolerance in Dayton, Alp, has been mapped to the long arm of chromosome 4H using RFLP markers. However, such markers are not useful for routine marker-assisted selection in breeding programs due to the cost and labour associated with their use. To increase the ease by which marker-assisted selection can be conducted for Alp, we sought to identify microsatellite markers linked to this gene. Several such markers that flank Alp were identified in a mapping population from a cross between Dayton and Harlan Hybrid. The most tightly linked microsatellite markers, HVM68 and Bmag353, flank Alp and are 5.3 cM and 3.1 cM from this locus, respectively. The linkage between Bmag353 and Alp was validated in a separate F3 population derived from the cross between Dayton and F6ant28B48-16, where this microsatellite marker was found to predict the Al tolerance phenotype with over 95% accuracy. Allele diversity for the 3 most tightly linked microsatellite markers was evaluated among 40 barley genotypes currently used in Australian barley breeding programs. The high levels of polymorphism detected among the genotypes with the markers indicated that the microsatellite markers, especially Bmag353 and Bmac310, will be broadly useful for marker-assisted selection of Alp in breeding programs seeking to improve Al tolerance.

Genome ◽  
2005 ◽  
Vol 48 (5) ◽  
pp. 781-791 ◽  
Author(s):  
Harsh Raman ◽  
Kerong Zhang ◽  
Mehmet Cakir ◽  
Rudi Appels ◽  
David F Garvin ◽  
...  

The major aluminum (Al) tolerance gene in wheat ALMT1 confers. An Al-activated efflux of malate from root apices. We determined the genomic structure of the ALMT1 gene and found it consists of 6 exons interrupted by 5 introns. Sequencing a range of wheat genotypes identified 3 alleles for ALMT1, 1 of which was identical to the ALMT1 gene from an Aegilops tauschii accession. The ALMT1 gene was mapped to chromosome 4DL using 'Chinese Spring' deletion lines, and loss of ALMT1 coincided with the loss of both Al tolerance and Al-activated malate efflux. Aluminium tolerance in each of 5 different doubled-haploid populations was found to be conditioned by a single major gene. When ALMT1 was polymorphic between the parental lines, QTL and linkage analyses indicated that ALMT1 mapped to chromosome 4DL and cosegregated with Al tolerance. In 2 populations examined, Al tolerance also segregated with a greater capacity for Al-activated malate efflux. Aluminium tolerance was not associated with a particular coding allele for ALMT1, but was significantly correlated with the relative level of ALMT1 expression. These findings suggest that the Al tolerance in a diverse range of wheat genotypes is primarily conditioned by ALMT1.Key words: aluminum, tolerance, genetic marker, Triticum aestivum, QTL, deletion mapping.


Genome ◽  
2002 ◽  
Vol 45 (4) ◽  
pp. 702-705 ◽  
Author(s):  
Eyal Blum ◽  
Kede Liu ◽  
Michael Mazourek ◽  
Eun Young Yoo ◽  
Molly Jahn ◽  
...  

Pungency owing to the presence of capsaicinoids is a unique character of pepper (Capsicum spp.). Capsaicinoids are produced in the placenta and it has long been known that a single dominant gene, C, is required for pungent genotypes to produce capsaicinoids. We mapped C to pepper chromosome 2 in a cross between a pungent Capsicum frutescens wild accession and a non-pungent Capsicum annuum bell pepper. This position confirmed results from earlier studies. The RFLP marker TG 205 cosegregated with C and two additional RFLP markers were also located within 1 cM. The recessive allele at the C locus is used in breeding programs around the world focused on very diverse germplasm, hence any of these tightly linked markers may be of value as potential sources of useful markers for marker-assisted selection. To demonstrate this point, we developed a PCR-based CAPS (cleaved amplified polymorphic sequence) marker linked to C using the sequence of the Capsicum fibrillin gene located 0.4 cM from C. The use of molecular markers for high-throughput screening for the c allele in pepper breeding programs is discussed.Key words: pepper, pungency, marker-assisted selection.


Toxins ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 319 ◽  
Author(s):  
James R. Tucker ◽  
Ana Badea ◽  
Richard Blagden ◽  
Kerri Pleskach ◽  
Sheryl A. Tittlemier ◽  
...  

Barley (Hordeum vulgare L.) is a multipurpose crop that can be harvested as grain or cut prior to maturity for use as forage. Fusarium head blight (FHB) is a devastating disease of barley that reduces quality of grain. FHB can also result in the accumulation of mycotoxins such as deoxynivalenol (DON). Breeding FHB resistant varieties has been a long-term goal of many barley-producing countries, including Canada. While the genetic basis of DON detoxification via production of less-phytotoxic conjugates such as DON-3-glucoside (DON3G) is well documented in barley, little information exists in reference to varietal response. Over two years, 16 spring, two-row barley genotypes, of importance to western Canadian barley breeding programs, were grown as short-rows and inoculated following spike emergence with a Fusarium graminearum conidia suspension. Half of the plots were harvested at soft dough stage and then dissected into rachis and grain components, whereas the remainder was harvested at maturity. Multiple Fusarium-mycotoxins were assayed using liquid chromatography-mass spectrometry. Mycotoxin content was elevated at the earlier harvest point, especially in the rachis tissue. DON3G constituted a significant percentage (26%) of total trichothecene content and thus its co-occurrence with DON should be considered by barley industries. DON3G was highly correlated with DON and 3-acetyl-deoxynivalenol (3ADON). The ratio of D3G/DON exhibited consistency across genotypes, however more-resistant genotypes were characterized by a higher ratio at the soft-dough stage followed by a decrease at maturity. Plant breeding practices that use DON content as a biomarker for resistance would likely result in the development of barley cultivars with lower total DON-like compounds.


2006 ◽  
Vol 57 (1) ◽  
pp. 113 ◽  
Author(s):  
Junping Wang ◽  
Harsh Raman ◽  
Barbara Read ◽  
Meixue Zhou ◽  
Neville Mendham ◽  
...  

Aluminium (Al) phytotoxicity is one of the major constraints for barley (Hordeum vulgare L.) production on acid soils. Genetic variation for Al tolerance is present in barley germplasm. Previous studies have shown that Al tolerance in cv. Dayton and WB229 is controlled by a single locus on 4H. The present study was conducted to investigate the genetic control of Al tolerance in Japanese barley cv. Honen, and validate the linkage relationship between the Al tolerance locus and the molecular markers established previously. An F3 progeny representing 94 F2s from the cross of F6ant28B48-16 (Al sensitive) × Honen (Al tolerant) was evaluated for Al tolerance by staining roots with eriochrome cyanine R. A single Al tolerance locus Alt was validated on the long arm of chromosome 4H in Honen. Single sequence repeat (SSR) markers Bmag353 and HVM68 flanked the Alt locus at a distance of 1.6 ± 0.9 and 5.1 ± 1.7 cM, respectively. Our results have shown that the linkage between SSR markers and the Al tolerance locus can be used to characterise the ‘unknown source’ for Al tolerance.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nicole Pretini ◽  
Leonardo S. Vanzetti ◽  
Ignacio I. Terrile ◽  
Guillermo Donaire ◽  
Fernanda G. González

Abstract Background In breeding programs, the selection of cultivars with the highest yield potential consisted in the selection of the yield per se, which resulted in cultivars with higher grains per spike (GN) and occasionally increased grain weight (GW) (main numerical components of the yield). In this study, quantitative trait loci (QTL) for GW, GN and spike fertility traits related to GN determination were mapped using two doubled haploid (DH) populations (Baguette Premium 11 × BioINTA 2002 and Baguette 19 × BioINTA 2002). Results In total 305 QTL were identified for 14 traits, out of which 12 QTL were identified in more than three environments and explained more than 10% of the phenotypic variation in at least one environment. Eight hotspot regions were detected on chromosomes 1A, 2B, 3A, 5A, 5B, 7A and 7B in which at least two major and stable QTL sheared confidence intervals. QTL on two of these regions (R5A.1 and R5A.2) have previously been described, but the other six regions are novel. Conclusions Based on the pleiotropic analysis within a robust physiological model we conclude that two hotspot genomic regions (R5A.1 and R5A.2) together with the QGW.perg-6B are of high relevance to be used in marker assisted selection in order to improve the spike yield potential. All the QTL identified for the spike related traits are the first step to search for their candidate genes, which will allow their better manipulation in the future.


2017 ◽  
Vol 1 (01) ◽  
pp. 46-51
Author(s):  
OUMER SHERIFF ◽  
KEFYALEW ALEMAYEHU

Sheriff O, Alemayehu K. 2017. Review: Genetic diversity studies using microsatellite markers and their contribution in supporting sustainable sheep breeding programs. Asian J Agric 1: 46-51. Microsatellites have been widely accepted and employed as useful molecular markers for measuring genetic diversity and divergence within and among populations. The various parameters developed so far to measure genetic diversity within and among populations are observed and expected heterozygosities (Ho and He), the mean number of alleles per locus (MNA),polymorphic information content (PIC), genetic distance and phylogenetic or tree building approach.The objective of thisreview was therefore to quantifythe genetic diversity studies of domestic sheep populations using microsatellite markersand their contribution in supporting sustainable sheep breeding programs. From the review, it is possible to see that there was high within population genetic variations in all the studied sheep populations, poor level of population differentiations and high levels of inbreeding. On the other hand, low estimates of hetrozygosities and mean number of alleles and employing only few and weak markers were observed in some of the studies. The gaps observed in the previous genetic diversity studies of the sheep populations may demand further works to reveal more information on the population structures andto start appropriate and sustainable breeding programs.


1993 ◽  
Vol 41 (5) ◽  
pp. 541 ◽  
Author(s):  
LM Egerton-Warbuton ◽  
BJ Griffin ◽  
BB Lamont

Selection for aluminium (Al) tolerance was assessed by studying pollen-pistil interactions in Eucalyptus calophylla trees colonising a 30-year-old abandoned coal mine-site (soil pH 4.3) compared with E. calophylla trees on an adjacent forest-site (soil pH 5.3). Energy-dispersive X-ray micro-analysis of reproductive tissues demonstrated that low levels of Al occurred in the stigma, lower style and unfertilised ovules of forest-site flowers. In contrast, significantly higher levels of Al were detected in all reproductive tissues of mine-site flowers. Al concentrations were higher at the base of the style than in the stigma. Al was also detected in stigmatic exudates of mine-site flowers. Selection for Al tolerance occurred in the anther of mine-site flowers as pollen from mine-site flowers germinated six-fold (15.6%) compared with forest-site pollen (2.6%) at the highest concentration of Al (22 ppm) used. However, the rate of pollen tube growth was not significantly different between mine- and forest-sites at any Al concentration. Tolerance of Al by the mine-site pollen was not shared by the progeny as there was no increase in the survival or growth of mine-site seedlings in mine soils over forest-site seedlings. Controlled pollinations between mine-/forest-site pollen and mine-site pistils demonstrated that there was no significant difference in the number of mine- or forest-site pollen tubes at any level in the style in mine-site pistils. Pollen tube abnormalities principally occurred in mine-site pistils. We concluded that there is no evidence yet for a genetically-based tolerance of Al in E. calophylla on coal mining soils.


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