Genus Alnus Research Articles

Twenty‐three microsatellite primer pairs for Betula pendula (Betulaceae)

AbstractThis paper reports the development of microsatellite primers for a widespread birch species Betula pendula. By screening genomic libraries with (TC)10 and (TG)10 probes, 38 microsatellite sequences were obtained, of which 23 proved to be polymorphic. Thirty genotyped individuals had two to 20 alleles per loci and a heterozygosity range of 0.17–0.92. Cross‐species amplification tests of four primer pairs on diverse birch species showed positive results in all cases. Also, one of two loci tested on related genus Alnus gave positive result.

Oregonin from the bark of European Alnus species

1. Subject and sourceThe genus Alnus comprises about 30 species of trees and shrubs that are foundin the Northern Hemisphere (Mitchell and Wilkinson, 1997). A. glutinosa and A.incana are common in northern Europe while A. viridis is found mainly in the alpineregion of the Alps (Bartels, 1993). A. cordata is native to southern Italy and Corsica(Polunin, 1976). The species examined in this study were A. glutinosa (L.) Gaertn.(collected near Altglobsow, Brandenburg, Germany, 22 November 1999 and 9 July2000, vouchers PL11-22-99, PL6-9-00),A. incana (L.) Moench (Military Street, nearWriedel and Schatensen, Germany, 23 May 2000, voucher PL5-23-00),A. viridis(Chaix) De Candolle (Botanical Garden Berlin-Dahlem, 6 June 2000, voucher PL6-6-00) andA. cordata (Loisel.) Duby (Skibbereen, Ireland, 1 August 2000, voucherPL8-1-00). Voucher specimens are deposited in the Department of Botany, Univer-sity of Leipzig, Germany.

Spittlebugs associated with actinorhizal host plants

Actinorhizal plants are major hosts for many spittlebugs, particularly species of the genera Clastoptera and Aphrophora. World host records indicate that at least 20 spittlebug species have primary associations with at least 17 actinorhizal hosts in the genera Alnus, Casuarina, Ceanothus, Comptonia, Elaeagnus, and Myrica. The highly polyphagic spittlebug, Philaenus spumarius (L.), has also been observed in association with Hippophaë and Coriaria. Several other spittlebugs have minor associations with actinorhizal hosts.Key words: actinorhizal plant, spittlebug, host, nitrogen-fixing.

Grouping of Frankia strains on the basis of susceptibility to antibiotics, pigment production and host specificity

Thirty-nine selected Frankia strains belonging to different genomic species were clustered on the basis of their in vitro susceptibility to 17 antibiotics, pigment production and ability to nodulate plants of the genus Alnus and/or the family Elaeagnaceae, or the family Casuarinaceae. The majority of the strains studied fell into three cluster groups, A, E and C, corresponding to the three host-specificity groups, Alnus, Elaeagnus and Casuarina. Within the groups, eight composite clusters, consisting of at least two strains, and five single-member clusters were recovered at the 0·74 distance level, in good agreement with levels of genetic relatedness between the strains. In addition, five strains were recovered as single-member clusters not in the cluster groups, four of them representing single-member genospecies and one strain not assigned to any known genospecies. The concordance between the phenotypic clusters and the genospecies described previously shows that the grouping may reflect the taxonomic structure of the genus Frankia. For some clusters, differentiating phenotypic characters were found which may be useful for species definition.

Chloroplast DNA phylogeography of Alnus glutinosa (L.) Gaertn.

Traditionally, information on the postglacial history of plant species has been gained from the analysis of fossil pollen data. More recently, surveys of present patterns of genetic variation have given valuable insights into species phylogeography. The genus Alnus, based on fossil data, is known to have had at least four glacial refugia. A survey of chloroplast DNA (cpDNA) diversity in populations of black alder (A. glutinosa) was undertaken in order to gain more insight into its postglacial history. This revealed a high degree of structuring of 13 cpDNA haplotypes on a European scale which indicated that most of northern and central Europe was colonized from a refuge in the Carpathian Mountains. Based on the distribution of two common cpDNA haplotypes, colonization routes from this refuge can be determined. The locations of other previously identified refugia are confirmed and two formerly unconfirmed refugial areas for alder (southern Spain and Turkey) are proposed.

The northern limit of Alnus (Fagales) in Costa Rica: modern pollen evidence of a possible range extension

The genus Alnus is represented in Costa Rica by one species. Alnus acuminara H.B.K.. a 5-20 m tall tree characteristic of montane forest formations (Furlow 1977). Burger (in Janzen 1983) stated that in Costa Rica A. acuminata is not known to occur north of Volcan Barva in the Cordillera Central. even though the species ranges northward to Mexico. However. Hartshorn and Poveda (in Janzen 1983) and Haber (1990) report A. acuminata to be present within the Monteverde reserve in the Cordillera de Tilaran (one range northwest of the Cordillera Central). According to Haber (1990), the species occurs as low as 90 m on the Atlantic slope, in the Rio Penas Blancas valley (approximate coordinates loo22'N, 84°38'W).

Genetic Diversity and Phylogenetic Relationships between Birches and Alders Using ITS, 18S rRNA, and rbcL Gene Sequences

The Betuleae is one of the two Betulaceae tribes and contains two genera, the actinorhizal genus Alnus and the nonactinorhizal genus Betula. To elucidate the phylogenetic relationships within the tribe and compare the relative amounts of genetic diversity between the genera Alnus and Betula, rbcL and 18S rRNA gene sequences as well as rDNA internal transcribed spacer (ITS1 and ITS2) sequences were obtained and compared. In rbcL and 18S rRNA, several substitutions were detected between Alnus and Betula but no variation was observed within Alnus. Minimal length variation was observed among ITS sequences. The numbers of substitutions per site for ITS were, on average, close to 10 times those estimated for 18S between Alnus and Betula. In ITS, numbers of substitutions were, on average, more than twice as large between genera than within genera. Phylogenies from ITS sequences were estimated using neighbor-joining analysis of substitution rates, maximum likelihood and parsimony methods. Each of the two genera appeared monophyletic, which was supported by high bootstrap estimates. Relationships among the three sections of Betula analyzed were also better resolved than those among the three subgenera of Alnus analyzed. Phylogenies estimated from ITS sequences suggested a relatively recent diversification of each genus, in agreement with fossil data.

Grouping of Frankia Strains on the Basis of DNA Relatedness

Summary The diversity among 27 Frankia strains was estimated by DNA-DNA hybridization (membrane filter method) and by determining DNA base compositions. The guanine + cytosine contents of DNA ranged from 69 to 73 mol%. The levels of DNA relatedness ranged from 3 to 100%, which allowed us to differentiate nine genospecies. Five genospecies were delineated among 18 strains compatible with plants of the genus Alnus (isolates from Alnus and Comptonia) and four genospecies were delineated among 9 strains compatible with plants of the family Elaeagnaceae (isolates from Elaeagnus, Hippophae, Shepherdia, and Colletia). Two additional strains were assigned to certain genospecies, since their total DNA restriction banding patterns and restriction fragment length polymorphism profiles were identical to those of representatives of these genospecies. The levels of DNA relatedness between members of the same genospecies ranged from 64 to 100%. In the Alnus host compatibility group, three genospecies displayed relatedness at the level of about 30% but were only 7 to 17% related to two other genospecies represented by single strains. In the Elaeagnaceae host compatibility group, strains from three genospecies showed relatedness at the levels of 15 to 36% but were only about 5% related to the fourth genospecies represented by a single strain. Low degrees of relatedness (3 to 20%) were also found between representatives of the two different host compatibility groups. The genospecies delineated cannot receive the status of nomenspecies, since few phenotypic criteria are available for their differentiation.

Deoxyribonucleic Acid Relatedness among Members of the Genus Frankia

The diversity among 43 isolates of the genus Frankia was studied by determining levels of deoxyribonucleic acid relatedness (SI nuclease method) and DNA base compositions. The guanine + cytosine contents ranged from 66 to 75 mol%. At least nine genomic species were differentiated, including three genomic species among strains compatible with members of the genus Alnus, five genomic species among strains compatible with members of the family Elaeagnaceae, and one genomic species among strains compatible with members of the genus Casuarina. Genomic species 1, which contained proposed type strain CpI1 and nine strains that were compatible with members of the genus Alnus and were 64 to 97 % related to strain ACoN24d, is Frankia alni. Four genomic species contained single strains that were 0 to 30% related to the other genomic species. Typical strains isolated from members of the genus Casuarina were found to be very homogeneous (69 to 100% related to strain ORS020606) and clearly separated from atypical strains. The nine genomic species delineated in this study cannot be named since no phenotypic tests are available for identification.

Phenylpropanoid patterns in fagales pollen and their phylogenetic relevance

The occurrence of hydroxycinnamic acid-spermidine amides and quercetin 3- O-glucosylgalactoside in pollen of Fagales and some other taxa of the Hamamelididae ( sensu Takhtajan and Cronquist) has been investigated. The genera Alnus, Betula, Corylus, and Quercus show characteristic patterns of N 1,N 10-di-( E)-feruloylspermidine, N 1, N 10-di-( E)-feruloylspermidine, N 1, N 10 -( E)-caffeoyl-( E)-feruloylspermidine and several N, N-di- p-coumaroylspermidines. The occurrence of these amides—together with some other unidentified hydroxycinnamic acid conjugates and quercetin 3- O-glucosylgalactoside—in extracts of the pollen grains support suggested relationships among Fagales, Juglandales, and Myricales.

Physiology, chemistry, serology, and infectivity of two Frankia isolates from Alnus incana subsp. rugosa

Actinorhizal nodules of Alnus incana ssp. rugosa collected from plants growing within 30 km of each other in Jeffersonville and Stowe, VT, U.S.A., yielded two morphologically distinct strains of Frankia. A comparison of the cell chemistry of the strains showed that each had the same type of cell wall and whole-cell sugar and phospholipid composition; however, AirI2 lacked the unknown amino acid found in the cells of all frankiae previously examined. Their cellular fatty acid composition showed only minor qualitative differences. Physiologically, the strains differed in their relation to oxygen, in their uptake and utilization of carbohydrates, organic acids, and lipids, and in protease production. AirI1 induced effective nodules in the host plant; those of AirI2 were ineffective. AirI2 was unrelated serologically to all frankiae previously isolated from the genus Alnus. AirI1 was serologically typical.

Ectomycorrhizal specificity in the genus Alnus

Only three of nine test fungi formed ectomycorrhizae on Alnus glutinosa, A. incana, A. rhombifolia, and A. sinuata in pure culture syntheses: Alpova diplophloeus, Astraeus pteridis, and Paxillus involutus. Pisolithus tinctorius formed ectomycorrhizae to a very limited extent on Alnus glutinosa. It is suggested that the entire genus Alnus may be very specialized regarding its ectomycorrhizal fungus associates, yet, display little infrageneric mycorrhizal specificity.The role of phenolics and possible mechanisms determining ectomycorrhizal specificity are discussed, and the need for research on host–fungus recognition factors is emphasized.

Flavonoidmuster im knospenexkret der betulaceen

In the Betulaceae, buds of the genus Alnus, Betula (Betuleae) and Ostrya (Coryleae) excrete a lipophilic “coat” consisting of terpenoids and flavonoid aglycones. The variation of the substitution pattern of these latter compounds has been investigated in relation to taxonomy. Characteristic compounds which occur are the methyl ethers of 6-hydroxykaempferol, ermanin (kaempferol-3,4′-Me), acacetin and pectolinarigenin. Other methyl derivatives of kaempferol, quercetin, apigenin and naringenin also occur more or less frequently. Evidence is given for the species-specifity of the flavonoid pattern in many of these exudates.

Exkretion von flavonoiden in der gattung Ostrya (Betulaceae)

Summary In the family Betulaceae the genus Alnus and Betula (tribe Betuleae) have been shown recently to produce flavonoid aglycones together with terpenoids as bud excretions. In this paper it is demonstrated that the genus Ostrya as the only member of the tribe Coryleae also excretes flavonoids. Most of these are rather rare methyl ethers of kaempferol and quercetine, which had been found in Alnus and/or Betula, too. Betulaceae seem to be especially enabled for biosynthesis of the derivatives of 6-hydroxy-kaempferol. Flavonoids from buds can be regarded as species-specific phytochemical characteristics.

Zum Vorkommen von δ-Amyrenon in Alnus-Arten / On the Occurrence of (δ-Amyrenone in Alnus-Species

δ-Amyrenon, known previously as constituent of leaves in the genus Alnus, is shown to form an important part of the triterpenoid excretions on buds of various alder-trees.