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Preliminary characterization of the self-incompatibility genotypes of European plum (Prunus domestica L.) cultivars
23-26.Views:210European plum is an important fruit crop with complex, hexaploid genome of unknown origin. The characterization of the selfincompatibility (S) locus of 16 European plum cultivars was carried out using the PaConsI-F primer in combination with the EM-PC1consRD primer for the first intron and the EM-PC2consFD and EM-PC3consRD primers for the second intron amplification. Altogether, 18 different alleles were scored indicating high genetic diversity. These alleles were labelled using alphabetical codes from SA to SS. We identified 5 different alleles in 9 cultivars, 4 alleles in 5 cultivars, while 3 alleles were shown in two of the assayed cultivars. A total of 16 different S-genotypes were assigned, and discrimination of all plum cultivars was successful based on their unique S-genotypes. However, further research is required to reliably identify the S-alleles based on their DNA sequence and clarify complete S-genotypes.
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Self-incompatibility alleles in Esatern European and Asian almond (Prunus dulcis) genotypes: a preliminary study
23-26.Views:183Almond [Prunus dulcis (Mill.) D. A. Webb.] as one of the oldest domesticated plants is thought to have originated in central Asia. Gametophytic self-incompatibility of almond is controlled by the highly polymorphic S-locus. The S-locus encodes for an S-ribonuclease (S-RNase) protein in the pistils, which degrades RNA in self-pollen tubes and hence stops their growing. This study was carried out to detect S-RNase allelic variants in Hungarian and Eastern European almond cultivars and Turkish wild growing seedlings, and characterize their S-allele pool. Five new alleles were identifi ed, S31H, S36-S39 in Eastern European local cultivars. The village Bademli and Akdamar island are two distinct places of almond natural occurrence in Turkey. Trees growing wild around Bademli city showed greater genetic diversity than those originated on Akdamar island. Many of the previously described 45 S-RNase alleles have been also detected in these regions. Homology searches revealed that Turkish almonds carried some P. webbii alleles indicating hybridization between the two cultivars and massive introgression events. Our results supply long-awaited information on almond S-allele diversity from regions between the main cultivation centres and the centre of origin of this species; and are discussed from the aspect of methodological developments and evolution of the cultivated almond.
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Characterization of quince (Cydonia oblonga Mill.) cultivars using SSR markers developed for apple
7-10.Views:306Quince (Cydonia oblongaMill.) is a minor fruit crop, which is primarily used for marmalade, jam and sauce.Very few quince cultivars are known all over the world and in many cases similar names are used for presumably different cultivars. The aim of the present study was to evaluate and characterize the genetic diversity of 36 quince cultivars and selections with SSR markers. Seven out of 8 SSR markers designed from apple sequences could successfully yield amplification also in quince cultivars. Number of alleles per locus ranged from 2 to 3 alleles. These allele numbers are quite low when compared to apple. It is supposed to be the consequence of a genetic bottleneck. In spite of the low allele number per locus, the 36 quince cultivars formed 30 different genotypes. The ratio of homozygosity was low, which might be coupled with the self-(in)compatibility phenotype of quinces. SSR markers proved unable to differentiate putatively closely related cultivars (e.g. ‘Bereczki’ and ‘Bereczki bôtermő’). In general, the level of polymorphism among the tested quince genotypes was much restricted due to the low allele number detected. However, it must be considered that the number of analysed SSR loci is not enough high to estimate the overall heterozygosity of the quince genome. Further experiments are needed and the SSR markers proved to be a reliable and useful tool for such analyses.
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Molecular identification of old Hungarian apple varieties
37-42.Views:242Altogether 40, mainly old Hungarian apple varieties were screened with six previously described microsatellite markers. A total of 71 polymorphic alleles were detected (average 11.8 alleles/locus) and the heterozygosity of markers averaged very high (0.8). The genetic variability among the genotypes proved to be so remarkable that as few as three markers from the applied six were enough to distinguish between the 40 varieties. This was also confirmed by the cumulative probability of obtaining identical allele patterns for two randomly chosen apple genotypes for all loci, which value was quite low: 2.53 x 10-5. The molecular identification of these genetically very different old apple genotypes could be very useful in future breeding programs.
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Self-(in)compatibility in sour cherry (Prunus cerasus L.). A minireview
117-120.Views:144Sour cherry (Prunus cerasus L.) is an allotetraploid species derived from hybridisation of the diploid sweet cherry (P avium L.) and the tetraploid ground cherry (P. fruticosa Pall.). Although numerous self-incompatible cultivars exist, the most sour cherry cultivars are self-compatible, which might be due to their tetraploid nature. This review is dedicated to show the limited information on the genetics of self-incompatibility in sour cherry accumulated during the last five years. Two different hypotheses (genomic arrangement of the alleles or the accumulation of non-functional S-haplotypes) are discussed. Heteroallelic sour cherry pollen was shown to be self-incompatible, which is counter to the Solanaceae where heteroallelic pollen frequently self-compatible due to a kind of competitive interaction between the two different alleles. This review highlights some inconsistencies in the hope that clarification will be achieved in the near future.
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Genotyping Hungarian apricot cultivars for self-(in)compatibility by isoelectric focusing and PCR analysis
69-72.Views:145Self-incompatibility (SI) in flowering plants is a widespread genetic system that promotes out-crossing. In Prunus species the SI is a gametophytic trait, which is controlled by a single multiallelic locus, termed S-locus. S-alleles codify stylar glycoproteins with ribonuclease activity (S-RNases). Our objective was to assess the S-genotype of some Hungarian apricot varieties by isoelectric focusing of stylar RNases as well as by PCR analysis using cherry consensus primers. Consensus primers amplified one or two bands of various sizes. Primers amplifying the 1st intron gained fragments the size of which ranged from 250 to 500 bp; while those amplifying the 2nd intron resulted in fragments of 800-2000 by length. Our data demonstrated that the first intron of the apricot S-RNase gene is shorter than the second one, which coincides with the structure of cherry S-RNase alleles. `Hargrand' (S1S2) and `Harcoe (S1S4) possessed one common S-RNase isoenzyme. Hungarian 'Orias' apricot cultivars showed different bands compared to the previous cultivars, but they shared completely identical patterns confirming that they possess the same S-genotype. 'Bergeron', `Harmat' and 'Korai zamatos' are characterised by an evidently distinct S-RNase pattern. The self-compatible cultivar (`Bergeron') had one allele, which suggests its correspondence to the Sc. Primers for the 2nd intron was unsuccessful in gaining fragments, which indicates that the 2nd intron in the Sc allele is too long to get any amplification. On the basis of our data, identities and differences were revealed in the S-allele constitution of some economically important Hungarian apricot cultivars at protein and DNA levels.
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S-locus genotyping on stone fruits in Hungary: a review of the most recent achievements
39-43.Views:198Central Europe can be taken as a geographical and historical connection zone between the western growing countries and Asian gene centres of Prunus tree fruits. The determination of the S-genotype of stone fruit (mainly almond, plum, cherries and apricot) cultivars and landraces has both practical and theoretical significance. Our group has allocated complete S-genotypes for more than 200 cultivars and selections of almond, Japanese plum, sweet cherry and apricot. Among Eastern European almond cultivars, two novel cross-incompatibility groups (CIGs) were identified. S-alleles of a related species were also shown in P. dulcis accessions; a fact seems to be indicative of introgressive hybridization. Our results with Japanese plum clarified and harmonized two different allele nomenclatures and formed a basis for intensive international studies. In apricot, a total of 13 new S-alleles were identified from Eastern European and Asian accessions. Many Turkish and North African cultivars were classified into new CIGs, III–XVII. Results suggest that the mutation rendering apricot self-compatible might have occurred somewhere in south-east of Turkey and we were successful to confirm the presumed Irano-Caucasian origin of North African apricots based on the geographical distribution of S-alleles. In sweet cherry, new alleles have been identified and characterized from Turkish cultivars and selections. In addition, wild sweet cherry and sour cherry S-alleles were also shown indicating a a broader gene pool in Turkey as compared with international cultivars. We also used S-genotype information of Ukrainian sweet cherry cultivars to design crosses in a functional breeding program. Our results exhibit an increased number of S-alleles in tree fruit accessions native to the regions from Eastern Europe to Central Asia, which can be used to develop S-genotyping methods, to assist cultivation and draw inferences for crop evolution.
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Determination of (in)compatibility genotypes of Hungarian sweet cherry (Prunus avium L.) accessions by PCR based methods
37-42.Views:163Sweet cherries (Prunus avium L.) are generally self-incompatible and pollinator cultivars are needed in orchards for reliable yield. In Hungary, choosing the appropriate cross-compatible cultivar pairs has so far been based on traditional test-crosses in the field. In recent years PCR-based methods that allow the identification of the S-alleles responsible for compatibility have been elaborated. We have determined the S-allele constitution of 24 cultivars and four selections important to Hungarian growers and breeders using PCR-based methods developed at Horticulture Research International, East Malling. The 28 accessions had various pairs of 9 alleles including one new allele, Sr. They could be assigned to 12 of the existing incompatibility groups or to a new group (S4S12) for which the designation 'Group XXVII' is proposed. The cultivars `Krupnoplodnaja' and 'Rita' had novel genotypes, S5S9 and S5Sx, respectively and can be placed into group 0 that holds universal pollen donors. The genotype of the cultivar ‘Hedelfingeni óriás' grown in Hungary was found to be S3S4 and therefore different from the cultivar `Hedelfingen' that is widespread in Western Europe.
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Studies on the Tobamovirus resistance of the pepper (Capsicum annuum L.) cultivar Greygo
71-75.Views:143Resistance of the Hungarian pepper (Capsicum annuum L.) cultivar "Gre.ygo" to Tohamoviruses has been investigated. All plants of the population of Greygo proved to be resistant to tobacco mosaic and tomato mosaic viruses (TMV, ToMV), both represent the pepper pathotypes Po of Tohamoviruses. Individuals of Greygo, however, were found to be susceptible to pathotypes P12 and P123 of pepper mild mottle virus (PMMV). When inoculated with the XM isolate of dulcamara yellow fleck virus (DYFV, pathotype P1) the population of Greygo segregated in resistant and susceptible plants. These results as well as inoculations of the progenies of three TMV resistant plants clearly showed, that besides the resistance allele Li the cultivar Greygo possesses also an another allele. This allele, provisionally marked by L2g behaves like to the allele L2 characteristic to Capsicum frutescens cv. . Tabasco. Determination of the identity of the allele L2g to the allele L2 needs further genetic and pathological informations. Relations between the Tohamoviruses pathogenic to pepper and the alleles of the resistance gene L are outlined for the discussion.
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Review of the self-incompatibility in apple (Malus x domestica Borkh., syn.: Malus pumila Mill.)
31-36.Views:506Apple (Malus x domestica Borkh.) is one of the most important fruit crops showing ribonuclease-mediated self-incompatibility, and no self-compatible apple cultivars are known. Twenty-nine S-alleles were identified in apple and many more incompatibility groups are present compared to sweet cherry. Results from a Belgian, English and a Japanese research group are combined and the S-genotypes of the most important world cultivars are collected. Two different allele labelling system are reconciled and detection methods used in case of the specific alleles are shown. Effects of the resistance breeding programmes are discussed; and scientific efforts involving transgenic technology to create self-compatible genotypes are shown. This review covers the most interesting issues regarding self-incompatibility in apple.