Dominance relationships among S-alleles in Corylus avellana L.

Summary Pollen-stigma compatibility relationship were studied in 50 cultivars and more than 800 seedlings of the European hazelnut (Corylus avellana L.). A total of 22 unique S-alleles have been identified. Dominance relationships in 75 of the possible 231 pairs of alleles have been determined in both pistil and pollen. In the pistil, all alleles exhibited independent action, whereas in the pollen, alleles exhibited either dominance or codominance. The dominance relationship was linear with 7 levels of dominance.Oregon Agricultural Experiment Station Technical Paper No. 8542     

Analysis of self-incompatibility interactions in 30 resynthesized Brassica napus lines. I. Fluorescence microscopic studies

Thirty Brassica napus lines have been developed through interspecific hybridization of B. oleracea and B. campestris lines with defined S-allele constitutions. These lines, which represent 29 different S-allele combinations, were tested in a diallel of test-pollinations to determine the activity of the introgressed S-alleles and intergenomic dominance relationships. Some consistent trends were observed: B. oleracea S-alleles high in the dominance series (e.g. S₈, S₁₄, S₂₉) were always active in the resynthesized B. napus lines, whereas recessive S-alleles (S₂, S₁₅) lost their activity in some test combinations. The B. campestris S-alleles were active in most cases, although 2 alleles were partially inactivated by the recessive B. oleracea allele S₁₅.     

Identification of pistil-specific proteins associated with three self-incompatibility alleles in Solanum chacoense

Summary Pistil proteins associated with three different S-alleles of the self-incompatibility locus (S locus) in Solanum chacoense have been identified which cosegregated with their respective S alleles in a series of genetic crosses involving six S. chacoense plants, their F₁ progeny, and backcrosses. The molecular weights of these three S-allele-associated proteins, designated S₁ S₂, and S₃, were 29 kDa, 30 kDa, and 31 kDa, respectively. They were all basic proteins with a similar pI of approximately 8.6. They have been found only in the stigma and style of the pistil where their maximum synthesis was reached at one day before anthesis. Their rate of synthesis in both self- and cross-pollinated pistils was the same as that in the unpollinated pistil until 2 days after pollination.On sabbatical leave from Laboratoire de Genetique et Physiologie du Developpement des Plantes, C.N.R.S., F-91190 Gifsur-Yvette, France     

New findings in apple S-genotype analysis resolve previous confusion and request the re-numbering of some S-alleles

Apple trees display gametophytic self-incompatibility which is controlled by a series of polymorphic S-alleles. To resolve the discrepancies in S-allele assignment that appeared in the literature, we have re-examined the identity of S-alleles known from domestic apple cultivars. Upon an alignment of S-allele nucleotide sequences, we designed allele-specific primer pairs to selectively amplify a single S-allele per reaction. Alternatively, highly similar S-alleles that were co-amplified with the same primer pair were discriminated through their distinct restriction digestion pattern. This is an extension of our previously developed allele-specific PCR amplification approach to reveal the S-genotypes in apple cultivars. Amplification parameters were optimised for the unique detection of the 15 apple S-alleles of which the nucleotide sequences are known. Both the old cultivars with a known S-genotype and a number of more common cultivars were assayed with this method. In most cases, our data coincided with those obtained through phenotypic and S-RNase analysis. However, three S-alleles were shown to relate to RNases that were previously proposed as being encoded by distinct S-alleles. For another S-allele the corresponding gene product has not been discriminated. Consequently, we propose the re-numbering of these four S-alleles. Furthermore, two alleles that were previously identified as S(27a) and S(27b) now received a distinct number, despite their identical S-specificity. To ease widespread future analysis of S-genotypes, we identified common cultivars that may function as a witness for bearing a particular S-allele. We discuss the assignment of new S-alleles which should help to avoid further confusion.     

Population structure and long-range linkage disequilibrium in a durum wheat elite collection

A collection of 134 durum wheat accessions, mainly including cultivars (cvs.) representative of the major gene pools, was assembled and characterized with 70 SSRs for genetic diversity and level of long-range linkage disequilibrium (LD). Results of both a distance-based and a model-based (Bayesian) cluster analysis evidenced the presence of a structured diversity. In the model-based analysis, six to eight main distinct subpopulations were identified based on the molecular data. Only a relatively small portion (20%) of the molecular variation was accounted for by the geographical origin of the accessions. Major differences were detected between the North American and the Mediterranean cvs., while a considerable overlap characterized the cvs. from CIMMYT-ICARDA and Italy. The North American cvs. showed the highest within group mean genetic similarity (GS_m = 0.68). French cvs. revealed sizeable similarities with both the North American as well as the Italian and CIMMYT-ICARDA pools. Considering the germplasm as a whole, high levels of LD were found both at locus pairs with an intrachromosomal distance <50 cM as well as at those with distances more than 50 cM and independent (86, 52 and 54% of SSR pairs at p < 0.01, respectively). After re-evaluating LD within each of the three main subgroups identified through the analysis of the germplasm structure, the LD level remained high for tightly to moderately linked locus pairs (<20 cM apart), but was greatly reduced in the loosely linked (more than 50 cM apart) and independent locus pairs. The implications of these findings as to the possibility of using association mapping for gene/QTL discovery in durum wheat are discussed.     

A high-throughput method for genotyping S-RNase alleles in apple

We present a new efficient screening tool for detection of S-alleles in apple. The protocol using general and multiplexed primers for PCR reaction and fragment detection on an automatized capillary DNA sequencer exposed a higher number of alleles than any previous studies. Analysis of alleles is made on basis of three individual fragment sizes making the allele interpretation highly accurate. The method was employed to genotype 432 Malus accessions and exposed 25 different S-alleles in a selection of Malus domestica cultivars of mainly Danish origin (402 accessions) as well as a selection of other Malus species (30 accessions). The allele S3 (28 %) was the most common among the Danish cultivars followed by S1 and S7 (both 27 %). The alleles S36 and S40 not previously reported from M. domestica were found in 6 and 17 cultivars, respectively. Complete allelic composition was found in 91 % of the 369 diploid accessions and in 86 % of the 63 triploids concerned. We further identified a relatively high frequency of S33 and S34, which has not been considered by most previous studies. The protocol presented here is easy to adopt and saves both time and work effort compared to previous methods. The robustness is illustrated by the great accuracy and a high number of S-alleles presented.     

A molecular approach to the identification of S-alleles in Brassica oleracea

A molecular technique for the identification of S-alleles involved in self-incompatibility has been used to analyse the S-allele reference collection of Brassica oleracea. The reference collection contains nearly 50 different lines each with a different S-allele present in the homozygous state. The technique consists of amplifying by the polymerase chain reaction (PCR) sequences belonging to the S multigene sequence family using a single pair of conserved primers. PCR products are then analysed further by digestion with six restriction enzymes followed by gel electrophoresis of the digestion products. A simple method of estimating the band sizes of the digestion products is described. The S-locus-related sequences can be distinguished from S-locus glycoprotein and S-receptor kinase genes by the restriction patterns. Furthermore, with any one restriction enzyme, several alleles showed the same restriction pattern. Alleles could therefore be grouped together. With two exceptions, each member of the S-allele reference collection showed a unique set of restriction patterns. Investigation of the exceptions using pollen tube growth tests showed that these accessions represented duplications within the collection. This technique therefore provides a simple and useful method for identifying different S-alleles.     

Microsatellite analysis reveals a progressive widening of the genetic basis in the elite durum wheat germplasm

It has been argued that the level of genetic diversity in the modern durum wheat (Triticum turgidum L. var. durum) elite germplasm may have declined due to the high selection pressure applied in breeding programs. In this study, 58 accessions covering a wide spectrum of genetic diversity of the cultivated durum wheat gene pool were characterized with 70 microsatellite loci (or simple sequence repeats, SSRs). On average, SSRs detected 5.6 different allelic variants per locus, with a mean diversity index (DI) equal to 0.56, thus revealing a diversity content comparable to those previously observed with SSRs in other small-grain cereal gene pools. The mean genetic similarity value was equal to 0.44. A highly diagnostic SSR set has been identified. A high variation in allele size was detected among SSR loci, suggesting a different suitability of these loci for estimating genetic diversity. The B genome was characterized by an overall polymorphism significantly higher than that of the A genome. Genetic diversity is organised in well-distinct sub-groups identified by the corresponding foundation-genotypes. A large portion (92.7%) of the molecular variation detected within the group of 45 modern cvs was accounted for by SSR alleles tracing back to ten foundation-genotypes; among those, the most recent CIMMYT-derived founders were genetically distant from the old Mediterranean ones. On the other hand, rare alleles were abundant, suggesting that a large number of genetic introgressions contributed to the foundation of the well-diversified germplasm herein considered. The profiles of recently released varieties indicate that the level of genetic diversity present in the modern durum wheat germplasm has actually increased over time.Communicated by F. Salamini     

Anoxia tolerance and α-amylase activity in four rice cultivars

The relationship between anoxia tolerance and reserved carbohydrate catabolism was investigated in four rice (Oryza sativa L.) cultivars subjected to a 48-h anoxic stress. The coleoptile elongation of all cultivars was suppressed by anoxic stress, however, the elongation of cvs Koshihikari and Awa-akamai was much greater than that of cvs Touzoumochi and Asahimochi. The anoxic coleoptiles of cvs Koshihikari and Awa-akamai contained about 2-fold as much ATP as those of cvs Touzoumochi and Asahimochi. Ethanol production in the anoxic coleoptiles of cvs Koshihikari and Awa-akamai was about 2-fold as much as that of cvs Touzoumochi and Asahimochi, which suggests that ethanolic fermentation is probably more active in cvs Koshihikari and Awa-akamai than in cvs Asahimochi and Touzoumochi. Activity of α-amylase, which catabolizes starch to soluble sugars, in endosperms of cvs Koshihikari and Awa-akamai was about 2-fold that of cvs Touzoumochi and Asahimochi, and soluble sugar concentration in the coleoptiles of cvs Koshihikari and Awa-akamai was about 3-fold greater than that of cvs Touzoumochi and Asahimochi. Soluble sugar concentration and ethanol production rate in the coleoptiles of rice seedlings were correlated well with α-amylase activity in their endosperms, which were also correlated well with anoxia tolerance with respect to the coleoptile elongation and ATP concentration in the coleoptiles. These results suggest that the ability to degrade starch to soluble sugar by α-amylase in endosperm may be important for the anoxia tolerance in rice coleoptiles and it may serve to distinguish the anoxia tolerance of rice coleoptiles.     

A simple method to estimate the percentage of hybridity in canola (Brassica napus) F1 hybrids

We have developed an efficient PCR-based system that uses RAPD markers for the certification of F₁ hybrids of canola. These markers were selected by screening five parental lines used in three crosses X, Y and Z with 131, 131 and 322 primers respectively. Stable DNA fragments that were homozygous and specific to the male inbreds were used to certify F₁ hybrid populations. The hybrid production system was based on self-incompatibility (SI) alleles that prevent self-pollination of the female parent. The efficiency of two S-alleles was compared under both field and greenhouse conditions. The percentage of hybridity was estimated in different F₁ populations. We found a significant difference between the two alleles for their efficiency in controlling selfing; both alleles were stable under greenhouse conditions, one allele appeared less reliable under field conditions.     

Identification of a new allele of Es-1 segregating in an inbred strain of mice

A new allele of Es-1, designated Es-1 ^e, has been identified in the mouse. This allele was discovered segregating among the progeny of a strain DBA/2J male and is apparently the result of a spontaneous mutation within this strain. Genetic analyses have shown that this mutation is heritable and, further, that both heterozygous and homozygous progeny are viable and fertile. To date, no discernible deleterious effects have been identified as associated with this mutation.     

Molecular characterization and association analysis with production traits of the porcine <Emphasis Type="Italic">INPP5F</Emphasis> Gene

Inositol polyphosphate-5-phosphatase F (INPP5F) is one of the largest families of phosphoinositide phosphatases, 5-phosphatase. It contains a Sac domain whose amino acids are essential for inositol polyphosphate phosphatase activities. Here, we assigned the porcine INPP5F to SSC14q29 by using SCHP and IMpRH. Sequencing of PCR products from different breeds identified an A/G polymorphism in the last exon. The allele frequencies of this SNP showed that the Yorkshire and Duroc pigs have high G allele frequency, whereas the local pigs have high A allele frequency. Association analysis of the genotypes with growth and carcass traits found that different genotypes of INPP5F have significant differences in average daily gain (ADG) (P < 0.05) in Yorkshire pigs.     

Characterization of the molecular defect in a null allele of the opaque-2 locus of maize

The molecular defect in an opaque-2 (o2) mutant, previously characterized as a null allele, has been identified as containing an insertion of the transposable element of the Bergamo (Bg) family. Restriction mapping and partial sequence analysis of the Bg in the o2 null allele indicates that this element is distinct from the previously described Bg as well as the defective Bg (rbg) of the o2m(r) allele. It is, however, inserted at the same site in O2 as the rbg of 62m(r) and can transpose when Bg is present. This study shows that, depending on genetic background, this allele may not behave as a stable null which could dramatically influence the conclusions drawn from experiments based on this particular mutant.     

Detection of RAPD polymorphisms inGladiolus cultivars with differing sensitivities toFusarium oxysporum f. sp.gladioli

Fusarium oxysporum Schlecht. Fr. F. sp.gladioli (FOG) is the most important gladiolus pathogen. One of the most environmentally friendly methods to control its spread is to use cultivars that are minimally sensitive to the pathogen. Infected corm tissues in more resistant varieties have been shown to produce suberin layers that inhibit fungal iphae growth. RAPD analysis of genomes from 9 selected gladiolus cvs, chosen to be the most resistant and sensitive to FOG, were performed to verify DNA polymorphism levels. Total nucleic acid extraction was carried out with a chloroform-phenol method from tissues of plants in 3 growth stages. RAPD experiments were performed using 14 primers with varyingTaq polymerases and primer concentrations. Five of the primers tested gave no polymorphic profiles. Five primers produced polymorphic bands, allowing us to obtain RAPD profiles typical for one or more of the more resistant cvs. All the tested growth stages provided repeatable results, indicating the reliability of detected polymorphisms. Cloning the more interesting polymorphic DNA fragments in the future will verify the presence of specific genes related to FOG resistance mechanisms in gladiolus.     

Coming to America: Acclimation in macaque body structures and Bergmann’s rule

I analyzed somatometric measurements from subsets of the Texas and Oregon transplanted troops of Japanese macaques(Macaca fuscata) to reveal secular changes in body size and shape. Body weights of the Texas population (N = 59) are lower than those of the Oregon population(N = 49) and the founding population from Arashiyama. The adult weights of the Oregon population are significantly higher than the founding population from Mihara. There are significant differences in adult circumferential measures and in skinfolds, which are correlated with the increased weight of the Oregon macaques. The adult Texas macaques have longer limb segments in comparison with the adult Oregon troop members, while the latter have significantly longer heads and trunks. Examination of the developing morphological trends through regression analyses on the complete sample suggests distinctive growth patterns for each population. Members of the Texas population start with smaller initial measurements but hold a steeper growth pattern for limb segments, while the Oregon macaques start larger in most measures and show lower growth rates. I argue that these differences in both somatometry and growth patterns are related to the differing climatic conditions under which the translocated macaques have lived. This set of analyses supports the basic arguments for Bergmann’s rule and Allen’s rule.     

Sequence of an S-protein of Lycopersicon peruvianum and comparison with other solanaceous S-proteins

Summary cDNA clones for an S-allele, designated S₅, of the self-incompatibility locus (S-locus) of Lycopersicon peruvianum have been isolated by probing a pistil cDNA library with cDNAs for S-alleles of Petunia inflata and Solanum chacoense. The longest S₅-cDNA is 869 bp and contains an open reading frame of 217 amino acids. An alignment of the deduced amino acid sequence of S₅-protein with that of the 18 S-proteins from five other solanaceous species is presented. Sequence comparison further refines the primary structural features of the S-proteins previously revealed from comparison of subsets of these sequences. Based on this comparison and evidence presented elsewhere, it is proposed that accumulation of point mutations, and not intragenic recombination, is responsible for the generation of new allelic specificities.     

Esterases of Mus musculus: Substrate and inhibition characteristics,new isozymes,and homologies with man

A wide range of fluorogenic and naphthol esters has been tested as substrates for mouse esterases. New esterases have been identified in liver and kidney extracts with palmityl, oleyl, and elaidyl esters. From substrate, inhibition, and molecular weight studies, three homologies between human and mouse esterases are suggested. A new allele at Es-6 is also described.This work was supported by the Medical Research Council.     

Analysis of self-incompatibility interactions in 30 resynthesized Brassica napus lines. II. Expression of S-locus glycoproteins (SLGs)

Thirty resynthesized Brassica napus lines with defined S-allele constitution and the ancestral B. oleracea and B. campestris lines were used for the analysis of S- locus glycoproteins (SLGs). The aim of this study was to investigate (1) whether the S-specific glycoproteins of the diploid ancestor lines were also expressed in the amphidiploid hybrids and (2) whether the occurrence of SLG bands was correlated with the activity of the respective S-alleles, which had been tested by means of diallele pollination tests in a previous study. Stigma proteins were separated by isoelectric focusing (IEF)-gel electrophoresis, and glycoprotein bands were identified by Western blotting and Con-A/peroxidase reaction. The SLG bands of the B. campestris parent could be detected in all 30 resynthesized B. napus lines. In contrast, B. oleracea SLG bands could only be detected in 12 resynthesized B. napus lines. Only B. napus lines which carried the dominant B. oleracea S-alleles S₈ and S₂₉ showed respective SLG bands in all cases. Nine B. napus lines showed only glycoprotein bands of the B. campestris parent, although the biological functioning of the B. oleracea S-alleles was demonstrated by test-pollinations. New SLG bands different from those of the B. oleracea and B. campestris parents occurred in 16 B. napus lines. The expression level of the SLGs in B. napus was not correlated with the self-incompatibility phenotype, not only in the case of recessive S-alleles (S₂, S₁₅), but also for dominant alleles (e.g. S₁₄, S₃₂, S₄₅). Received: 22 January 1999 / Accepted: 30 January 1999     

Characterization of three new S-alleles and development of an S-allele-specific PCR system for rapidly identifying the S-genotype in apple cultivars

Apple (Malus domestica Borkh), a member of the Rosaceae, shows gametophytic self-incompatibility (GSI) controlled by polymorphic S-alleles. Identifying the S-genotypes of apple cultivars can be applied on correct assignment of apple cultivars to cross-compatibility groups, which is important for the efficient production of apple fruit. This study characterized three new S-alleles (designated S ₄₄ , S ₄₅ , and S ₄₆ ) in apple and developed an efficient analysis method that can be used to characterize S-genotypes by utilizing allele-specific polymerase chain reaction rapidly. Nineteen allele-specific primers were selectively designed to identify different alleles. Using this method, S-genotypes of 157 apple cultivars were identified.     

Introduction and establishment ofTrioxys pallidus [Hym.: Aphidiidae] in Oregon,U.S.A. for control of filbert aphidMyzocallis coryli [Hom.: Aphididae]

Hazelnut orchards in Spain, France, and Italy were searched for parasitoids of the filbert aphid,Myzocallis coryli (Goetze). A biotype ofTrioxys pallidus Haliday was found to parasitize the aphid throughout western Europe. Wasps were imported, quarantined, mass-reared, and released in Oregon orchards. The wasp successfully attacked and completed its development on Oregon populations of the filbert aphid. A greenhouse culture of the parasitoid was maintained continuously for over 50 generations, and approximately 30,000 adult wasps were released in western Oregon. Overwintering survival has been documented in at least 12 different locations. In 3 commercial hazelnut orchards, the parasitoids proved capable of reducing aphid population peaks by 33–48%.