RAPD analysis of diploid and tetraploid populations of Aronia points to different reproductive strategies within the genus

×Sorbaronia mitschurinii: from an artificially created species to an invasion in Europe: repeating the fate of invasive Amelanchier ×spicata, a review

By intervening in natural events, relocating species to other areas, purposefully hybridizing them, as well as reducing the habitats required for them, humans have created conditions for new hybrid species to emerge. As long as hybrids exist in our gardens and fields, we have no reason to worry. However, problems arise with the expansion of these hybrid species into natural habitats, where such hybrid species cannot always be recognized and remain unnoticed, and in most cases they are often mistaken for natural parent species. Two hybrid species, Amelanchier ×spicata and ×Sorbaronia mitschurinii have historically developed in Europe with different scenarios of origin. It has been suggested in the past that both species are of hybrid origin, and recent molecular studies have confirmed the previous assumptions. There is no doubt that A. ×spicata originated in a natural way of hybridization, when the two parental species came into contact in Europe, but ×S. mitschurinii is a purposefully created species, crossing ×Sorbaronia fallax with Aronia melanocarpa. Produced as a result of different scenarios, these two hybrid species have become invasive in Europe, and ×S. mitschurinii has started to follow in the footsteps of the highly invasive A. ×spicata, spreading in the wild, where it predominantly expands in pine forests and in wetland forests along water bodies and bogs. Moreover, ×S. mitschurinii occupies the same habitats in Europe as one of its parent plants, A. melanocarpa in North America, and this species is a threat to wetland forest habitats. Given that ×S. mitschurinii has long been regarded as one of Aronia species, the exact distribution of the species in Europe is unknown, but the following countries are currently reporting the presence of the species in Europe: Belarus, Belgium, Czech Republic, Estonia, Finland, Latvia, Lithuania, Netherlands, Norway, Poland, Russian Federation, Sweden, Ukraine and United Kingdom. In the light of current knowledge, further studies on ×S. mitschurinii invasion in Europe are needed, as well as the need to correct the information in international databases, such as CABI, NOBANIS, to separate ×S. mitschurinii data from what applies to Aronia taxa.

Morphological characteristics for fruits of aronia mitschurinii A.K. Skvortsov & Maitul

The aim of this study was to determine morphometric characteristics of fruits within some phenotypes of Aronia mitschurinii A.K. Skvortsov & Maitul. Their morphometric parameters were following: weight from 0.75 g (AM-03) to 1.52 g (AM-04), length from 9.46 mm (AM-03) to 12.73 mm (AM-04), diameter from 10.49 mm (AM-03) to 13.73 mm (AM-04), fruits number in the corymb from 11.33 (AM-07) to 20.13 (AM-03), cumulative weight of fruits in the corymb from 10.42 g (AM-07) to 21.73 g (AM-04), volume of fruits from 0.55 (AM-03) to 1.26 (AM-04) cm3. The shape index of the fruits was found in the range of 0.87 (AR-01, AR-05, AR-07) to 0.93 (AM-02). The analysis of coefficient of variation showed the difference of variability in morphological characteristics between Aronia mitschurinii samples. Data showed that the most variability of important selection characteristics are the average cumulative mass of fruits in a сorymb - from 12.34 (AM-03) to 38.61 (AM-02) % and fruit number of fruits in the сorymb - from 14.56 (AM-03) to 36.88 (AM-02) %. The other characteristics are more or less stable. The introduction population of the Aronia mitschurinii, was created in the M.M. Gryshko National Botanical Garden in Kyiv, has a sufficient potential for successful selection work.

Phenolic Content, Antioxidant Capacity and Quality of Chokeberry (Aronia melanocarpa) Products

Chokeberries (Aronia melanocarpa) are rarely used in diet in Croatia but they have high content of polyphenolic compounds and one of the highest in vitro antioxidant activities among fruits. The aim of this study is to compare the quality, phenolic content and antioxidant capacity of different chokeberry products (juices, powders, fruit tea, capsules and dried berries). It can be expected that processing influences antioxidant activity and phenolic content of final products reaching consumers. Characterisation of phenolic compounds was carried out by using spectroscopic methods (Folin-Ciocalteu and pH differential methods). Antioxidant activity of chokeberry products was determined using 2,2-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods. The results show that the investigated products contain high amount of phenols (3002 to 6639 mg per L and 1494 to 5292 mg per 100 g of dry matter) and lower amount of total anthocyanins (150 to 1228 mg per L and 141 to 2468 mg per 100 g of dry matter). The examined juices and other chokeberry products possess high antioxidant capacity (12.09 to 40.19 mmol per L or 58.49 to 191.31 mmol per 100 g of dry matter, respectively) and reducing power (38.71 to 79.86 mmol per L or 13.50 to 68.60 mmol per 100 g of dry matter, respectively). On the basis of phenolic content and antioxidant activity, capsules and powders stand out among other products. The study indicates that there are significant differences (p<0.05) in the quality, phenolic content and antioxidant capacity among examined products.

Effects of apomixis and polyploidy on diversification and geographic distribution in Amelanchier (Rosaceae)

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PREMISE OF THE STUDY

Amelanchier polyploid apomicts differ from sexual diploids in their more complex diversification, greater species problems, and geographic distribution. To understand these differences, we investigated the occurrence of polyploidy and frequency of apomixis. This research helps clarify species delimitation in an evolutionarily complex genus.•

METHODS

We used flow cytometry to estimate genome size of 1355 plants. We estimated the frequency of apomixis from flow-cytometrically determined ploidy levels of embryo and endosperm and from a progeny study using RAPD markers. We explored relationships of triploids to other ploidy levels and of ploidy levels to latitude plus elevation.•

KEY RESULTS

Diploids (32% of sample) and tetraploids (62%) were widespread. Triploids (6%) mostly occurred in small numbers with diploids from two or more species or with diploids and tetraploids. Seeds from diploids were 2% apomictic, the first report of apomixis in Amelanchier diploids. Seeds from triploids were 75% apomictic. We documented potential triploid bridge and triploid block from unbalanced endosperm and low pollen viability. Seeds from tetraploids were 97% apomictic, and tetraploids often formed microspecies. We did not find strong evidence for geographical parthenogenesis in North American Amelanchier. Most currently recognized species contained multiple ploidy levels that were morphologically semicryptic.•

CONCLUSIONS

Documentation of numerous transitions from diploidy to polyploidy helps clarify diversification, geographic distribution, and the species problem in Amelanchier. Despite the infrequent occurrence of triploids, their retention of 25% sexuality and capacity for triploid bridge may be important steps between sexual diploids and predominantly apomictic tetraploids.

Fine-scale comparisons of genetic variability in seed families of asexually and sexually reproducing Crataegus (hawthorn; Rosaceae)

The reproductive system is one of the key mechanisms that determine genetic diversity at different biological levels. However, few attempts have been made to assess the consequences of asexual reproduction by comparing genetic structure and fecundity of seed families in asexually and sexually reproducing individuals. We have examined two similar hawthorn species, Crataegus crus-galli and C. punctata, that differ in ploidy level and breeding system. Fecundity (per-fruit seed set) and microsatellite genotypes for five loci were determined in 18 and 26 seed families of C. crus-galli and C. punctata (totals of 83 and 118 embryos), respectively. Compared with the sexual diploid C. punctata, tetraploid C. crus-galli shows similar fecundity, but lower genotypic diversity within and between seed families. Reproduction in the tetraploid, while predominantly apomictic, is nevertheless accompanied by outcrossing and selfing. We conclude that in C. crus-galli pollen flow between conspecific individuals is limited, and the combination of pollen fertility, self-compatibility, and pseudogamous apomixis provides reproductive assurance in these tetraploids. Reproductive assurance, in turn, may explain the derived floral architecture seen in most North American tetraploid hawthorns. We also discuss analytical approaches for inferring mating-system parameters in tetraploids and for comparing microsatellite variation across ploidy levels.

Population genetic structure of diploid sexual and polyploid apomictic hawthorns (Crataegus; Rosaceae) in the Pacific Northwest

Polyploidy and gametophytic apomixis are two important and associated processes in plants. Many hawthorn species are polyploids and can reproduce both sexually and apomictically. However, the population genetic structure of these species is poorly understood. Crataegus douglasii is represented exclusively by self-compatible tetraploid pseudogamous apomicts across North America, whereas Crataegus suksdorfii found in the Pacific Northwest is known to include self-incompatible diploid sexuals as well as polyploid apomicts. We compare population structure and genetic variability in these two closely related taxa using microsatellite and chloroplast sequence markers. Using 13 microsatellite loci located on four linkage groups, 251 alleles were detected in 239 individuals sampled from 15 localities. Within-population multilocus genotypic variation and molecular diversity are greatest in diploid sexuals and lowest in triploid apomicts. Apart from the isolation of eastern North American populations of C. douglasii, there is little evidence of isolation by distance in this taxon. Genetic diversity in western populations of C. douglasii suggests that gene flow is frequent, and that colonization and establishment are often successful. In contrast, local populations of C. suksdorfii are more markedly differentiated. Gene flow appears to be limited primarily by distance in diploids and by apomixis and self-compatibility in polyploids. We infer that apomixis and reproductive barriers between cytotypes are factors that reduce the frequency of gene flow among populations, and may ultimately lead to allopatric speciation in C. suksdorfii. Our findings shed light on evolution in woody plants that show heterogeneous ploidy levels and reproductive systems.

Ingestion of black chokeberry fruit extract leads to intestinal and systemic changes in a rat model of prediabetes and hyperlipidemia

This report presents a complex analysis of changes proceeding in the gut, blood and internal organs of rats with induced oxidative stress, glucose intolerance and hyperlipidemia after dietary supplementation with an extract from black chokeberry (Aronia melanocarpa) fruit, that is a condensed source of polyphenols (714 mg/g), especially anthocyanin glycosides (56.6%). The disturbances mimicking those observed in metabolic syndrome were induced by a high-fructose diet and simultaneous single injection of streptozotocin (20 mg/kg). Dietary supplementation with the chokeberry fruit extract (0.2%) decreased activity of maltase and sucrase as well as increased activity of lactase in the mucosa of the small intestine. Its ingestion led also to the improvement of antioxidant status, especially, the concentration of a lipid peroxidation indicator (TBARS) in organ tissues (liver, kidney and lung) was normalized; some cholesterol-lowering and distinct hypoglycemic actions were also observed. The mechanism of glucose reduction is likely to be multifactorial, and we suggest the factors related with the decreased activity of mucosal disaccharidases important for further investigation. In conclusion, chokeberry fruit derivatives may act as a promising supplementary therapeutic option in the prevention and treatment of disorders occurring in metabolic syndrome, as well as their complications.

Microsatellite analysis of genetic variation and population genetic differentiation in autotetraploid and diploid rice

Genetic diversity and population genetic structure of autotetraploid and diploid populations of rice collected from Chengdu Institute of Biology, Chinese Academy of Sciences, were studied based on 36 microsatellite loci. Among 50 varieties, a moderate to high level of genetic diversity was observed at the population level, with the number of alleles per locus (Ae) ranging from 2 to 6 (mean 3.028) and polymorphism information content ranging from 0.04 to 0.76 (mean 0.366). The expected heterozygosity (He) varied from 0.04 to 0.76 (mean 0.370) and Shannon's index (I) from 0.098 to 1.613 (mean 0.649). The autotetraploid populations showed slightly higher levels of Ae, He, and I than the diploid populations. Rare alleles were observed at most of the simple sequence repeat loci in one or more of the 50 accessions, and a core fingerprint database of the autotetraploid and diploid rice was constructed. The F-statistics showed genetic variability mainly among autotetraploid populations rather than diploid populations (Fst = 0.066). Cluster analysis of the 50 accessions showed four major groups. Group I contained all of the autotetraploid and diploid indica maintainer lines and an autotetraploid and its original diploid indica male sterile lines. Group II contained only the original IR accessions. Group III was more diverse than either Group II or Group IV, comprising both autotetraploid and diploid indica restoring lines. Group IV included a japonica cluster of the autotetraploid and diploid rices. Furthermore, genetic differences at the single-locus and two-locus levels, as well as components due to allelic and gametic differentiation, were revealed between autotetraploid and diploid varieties. This analysis indicated that the gene pools of diploid and autotetraploid rice were somewhat dissimilar, as variation exists that distinguishes autotetraploid from diploid rices. Using this variation, we can breed new autotetraploid varieties with some important agricultural characters that were not found in the original diploid rice varieties.