Genetic diversity and relationships in some <Emphasis Type="Italic">Vicia</Emphasis> species as determined by SDS-PAGE of seed proteins

To evaluate the genetic diversity of some Vicia species, seed proteins of 160 accessions (30 of Vicia faba, 15 of V. narbonensis, 82 of V. sativa and 25 of V. ervilia and 8 accessions of other Vicia species) were analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The dendrogram showed that the two outcrossing species V. faba and V. villosa were the most distant among all species (average percent disagreement value PDV 0.47 and 0.45, respectively). The tree was divided into small clusters of two species each. V. narbonensis fell in one cluster with V. michausai (at PDV = 0.35) and V. lutea (var. hirta) fell in one cluster with V. serococorpes (at PDV = 0.32) whereas, V. ervilia fell in one cluster with V. sativa (at PDV = 0.27). The V. sativa subspecies, however, were closely related (PDV < 0.1). In general, this study did not prove any relationship between the studied storage proteins and the geographical distribution or ecological needs of the studied accessions.     

Genetic Diversity and Population Structure of Tetraploid Wheats (Triticum turgidum L.) Estimated by SSR,DArT and Pedigree Data

Levels of genetic diversity and population genetic structure of a collection of 230 accessions of seven tetraploid Triticum turgidum L. subspecies were investigated using six morphological, nine seed storage protein loci, 26 SSRs and 970 DArT markers. The genetic diversity of the morphological traits and seed storage proteins was always lower in the durum wheat compared to the wild and domesticated emmer. Using Bayesian clustering (K = 2), both of the sets of molecular markers distinguished the durum wheat cultivars from the other tetraploid subspecies, and two distinct subgroups were detected within the durum wheat subspecies, which is in agreement with their origin and year of release. The genetic diversity of morphological traits and seed storage proteins was always lower in the improved durum cultivars registered after 1990, than in the intermediate and older ones. This marked effect on diversity was not observed for molecular markers, where there was only a weak reduction. At K >2, the SSR markers showed a greater degree of resolution than for DArT, with their identification of a greater number of groups within each subspecies. Analysis of DArT marker differentiation between the wheat subspecies indicated outlier loci that are potentially linked to genes controlling some important agronomic traits. Among the 211 loci identified under selection, 109 markers were recently mapped, and some of these markers were clustered into specific regions on chromosome arms 2BL, 3BS and 4AL, where several genes/quantitative trait loci (QTLs) are involved in the domestication of tetraploid wheats, such as the tenacious glumes (Tg) and brittle rachis (Br) characteristics. On the basis of these results, it can be assumed that the population structure of the tetraploid wheat collection partially reflects the evolutionary history of Triticum turgidum L. subspecies and the genetic potential of landraces and wild accessions for the detection of unexplored alleles.     

A multivariate and cladistic study of Vicia L. ser. Vicia (Fabaceae) based on analysis of morphological characters

 Vicia ser. Vicia, which includes the Vicia sativa aggregate, was studied by observing morphological variation. The study is an attempt to resolve the taxonomic relationships within the Vicia sativa aggregate by novel investigations along with a synthesis of the results obtained by previous researchers. The study has included some accessions and characters used previously, but has drawn accessions from a wider geographical range than has been attempted previously. Cluster analysis on the basis of 53 morphological characters justified the delimitation of four species within the series and six subspecies within the Vicia sativa aggregate. Accessions from South Asia could easily be incorporated in the classification, but some of the accessions from North Africa showed morphological differences. The morphometric data were coded using the gap weighting method of Thiele (1993) and used in a phylogenetic analysis to study the relationships between the taxa. The phylogenetic analysis, using 33 variables, showed Vicia pyrenaica closely related to Vicia sativa subsp. amphicarpa. A dichotomous key and a multi-access key to aid the identification of the taxa in the series are presented. Received January 21, 2002; accepted November 8, 2002 Published online: March 20, 2003     

Seed protein polymorphism inVicia sativa agg. (Fabaceae)

TheVicia sativa aggregate contains plants with different chromosome numbers karyotypes; they are still cross-compatible and have partially fertile F₁-hybrids. There is also wide adaptive radiation and geographic distribution. The seed protein profiles ofV. sativa agg. are remarkably variable but no band or bands could be related to a specific karyotype, chromosome number or taxon, and variation within and between karyotypes are of the same magnitude. It is suggested that variation in the seed proteins ofV. sativa agg. might be an important agent for acquiring ecological flexibility, and that it is probably enhanced by interkaryotypic hybridization.     

Seed protein fraction electrophoresis in peanut (<Emphasis Type="Italic">Arachis hypogaea</Emphasis> L.) accessions and wild species

Total seed storage proteins were studied in 50 accessions of A. hypogaea (11 A. hypogaea ssp. hypogaea var hypogaea, 13 A. hypogaea ssp. hypogaea var hirsuta, 11 A. hypogaea ssp. fastigiata var fastigiata and 15 A. hypogaea ssp. fastigiata var. vulgaris accessions) in SDS PAGE. These accessions were also analysed for albumin and globulin seed protein fractions. Among the six seed protein markers presently used, it was found that globulin fraction showed maximum diversity (77.2%) in A. hypogaea accessions followed by albumin (52.3%), denatured total soluble protein fraction in embryo (33.3%) and cotyledon (28.5%). The cluster analysis based on combined data of cotyledons, embryos, albumins and globulins seed protein fractions demarcated the accessions of two subspecies hypogaea and fastigiata into two separate clusters supported by 51% bootstrap value, with few exceptions, suggesting the genotypes to be moderately diverse. Native and denatured total soluble seed storage proteins were also electrophoretically analysed in 27 wild Arachis species belonging to six sections of the genus. Cluster analysis using different methods were performed for different seed proteins data alone and also in combination. Section Caulorrhizae (C genome) and Triseminatae (T genome) formed one, distantly related group to A. hypogaea and other section Arachis species in the dendrogram based on denatured seed storage proteins data. The present analysis has maintained that the section Arachis species belong to primary and secondary genepools and, sections Procumbenetes and Erectoides belong to tertiary gene pools.     

Diversity of seed storage protein patterns in wild peanut (Arachis,Fabaceae) species

55 accessions of wild peanuts (Arachis spp.) introduced from South America were analyzed for seed storage protein composition using SDS-PAGE electrophoresis. The objectives of the study were to evaluate variability within sect.Arachis and to classify taxa based on protein composition. 25 different band positions were resolved. Individual accessions had 11 to 18 bands which included the conarachin region (MW > 50 kD), two to five bands in the acidic arachin region (MW 38–49.9 kD), three to seven in the intermediate MW region (23 to 37.9 kD), two to five bands in the basic arachin region (18–22.9 kD), and one to three bands in the low MW protein region (14–17.9 kD). These data were utilized in a principal coordinate analysis based on the matrix of genetic distances between all pairs of the 55 accessions. Several groups of accessions conformed to expected species classification includingA. batizocoi, A. stenosperma, andA. monticola; whileA. duranensis, A. cardenasii, A. helodes, andA. correntina did not form good groups. The study showed that great diversity exists for protein profiles and seed storage proteins have potential for aiding species classification and for serving as markers for interspecific hybridization studies.     

Variation in seed packaging of a fleshy‐fruited conifer provides insights into the ecology and evolution of multi‐seeded fruits

• The study of intraspecific seed packaging (i.e. seed size/number strategy) variation across different populations may allow better understanding of the ecological forces that drive seed evolution in plants. Juniperus thurifera (Cupressaceae) provides a good model to study this due to the existence of two subspecies differentiated by phenotypic traits, such as seed size and cone seediness (number of seeds inside a cone), across its range.
• The aim of this study was to analyse seed packaging (seed mass and cone seediness) variation at different scales (subspecies, populations and individuals) and the relationship between cone and seed traits in European and African J. thurifera populations.
• After opening more than 5300 cones and measuring 3600 seeds, we found that seed packaging traits followed different patterns of variation. Large‐scale effects (region and population) significantly contributed to cone seediness variance, while most of the seed mass variance occurred within individuals. Seed packaging differed between the two sides of the Mediterranean Sea, with African cones bearing fewer but larger seeds than the European ones. However, no differences in seed mass were found between populations when taking into account cone seediness. Larger cones contained more pulp and seeds and displayed a larger variation in individual seed mass.
• We validated previous reports on the intraspecific differences in J. thurifera seed packaging, although both subspecies followed the same seed size/number trade‐off. The higher seediness and variation in seed mass found in larger cones reveals that the positive relationship between seed and cone sizes may not be straightforward.We hypothesise that the large variation of seed size found within cones and individuals in J. thurifera, but also in other fleshy‐fruited species, could represent a bet‐hedging strategy for dispersal.

     

Electrophoretic seed albumin patterns inVicia species of sectt.Hypechusa andPeregrinae (Fabaceae)

This work is a continuation of electrophoretic investigations aimed at revealing a wild relative ofVicia faba. Electrophoretic analysis (PAGE) of seed albumins covered 52 accessions representing eightVicia species of sect.Hypechusa and two species of sect.Peregrinae. Most of the examined species showed an intraspecific variation due to differences between accessions and/or individual variation within accessions. In spite of the intraspecific variation, marked interspecific differences were recorded. However, none of the investigated species displayed electrophoretic seed albumin patterns similar to those reported earlier forV. faba. Contribution of the obtained results to characterization of the examined taxa is discussed.     

Proteomic insights into seed germination in response to environmental factors

Seed germination is a critical process in the life cycle of higher plants. During germination, the imbibed mature seed is highly sensitive to different environmental factors. However, knowledge about the molecular and physiological mechanisms underlying the environmental effects on germination has been lacking. Recent proteomic work has provided invaluable insight into the molecular processes in germinating seeds of Arabidopsis, rice (Oryza sativa), soybean (Glycine max), barley (Hordeum vulgare), maize (Zea mays), tea (Camellia sinensis), European beech (Fagus sylvatica), and Norway maple (Acer platanoides) under different treatments including metal ions (e.g. copper and cadmium), drought, low temperature, hormones, and chemicals (gibberellic acid, abscisic acid, salicylic acid, and α‐amanitin), as well as Fusarium graminearum infection. A total of 561 environmental factor‐responsive proteins have been identified with various expression patterns in germinating seeds. The data highlight diverse regulatory and metabolic mechanisms upon seed germination, including induction of environmental factor‐responsive signaling pathways, seed storage reserve mobilization and utilization, enhancement of DNA repair and modification, regulation of gene expression and protein synthesis, modulation of cell structure, and cell defense. In this review, we summarize the interesting findings and discuss the relevance and significance for our understanding of environmental regulation of seed germination.     

Intra and inter subspecific variation in soluble proteins of Oryza sativa L.

Summary Types representing three subspecies of Oryza sativa, namely, indica, japonica and javanica, and a group of intermediate types collected from North East India, were studied for variation in soluble proteins using acrylamide gel electrophoresis. The study revealed that there was a marked variation within and between varietal groups. Variability for number and intensity of protein bands in indica was wider than in japonica and javanica. Protein pattern in the group comprising N.E. Indian types transgressed that of all three established groups by displaying a wide spectrum. Relative homology, as measured from percentage similarities of N.E. Indian types to the three subspecies, suggested the existence of six different groups. Comparison of varietal groups for the protein mobility pattern showed that japonica and javanica varieties tended to show higher percentages of slow mobility proteins than indica. It appears, from the narrow variability and relatively low percentage of slow mobility proteins, that the japonica and javanica races are of later origin compared to indica. However, the study with a limited number of types suggested the monophyletic origin of varietal groups from an indica-like base predominantly found in the secondary centres of origin of O. sativa.     

Genetic relationships and evolution in <Emphasis Type="Italic">Cucurbita pepo</Emphasis> (pumpkin,squash, gourd) as revealed by simple sequence repeat polymorphisms

Genetic relationships among 104 accessions of Cucurbita pepo were assessed from polymorphisms in 134 SSR (microsatellite) and four SCAR loci, yielding a total of 418 alleles, distributed among all 20 linkage groups. Genetic distance values were calculated, a dendrogram constructed, and principal coordinate analyses conducted. The results showed 100 of the accessions as distributed among three clusters representing each of the recognized subspecies, pepo, texana, and fraterna. The remaining four accessions, all having very small, round, striped fruits, assumed central positions between the two cultivated subspecies, pepo and texana, suggesting that they are relicts of undescribed wild ancestors of the two domesticated subspecies. In both, subsp. texana and subsp. pepo, accessions belonging to the same cultivar-group (fruit shape) associated with one another. Within subsp. pepo, accessions grown for their seeds or that are generalists, used for both seed and fruit consumption, assumed central positions. Specialized accessions, grown exclusively for consumption of their young fruits, or their mature fruit flesh, or seed oil extraction, tended to assume outlying positions, and the different specializations radiated outward from the center in different directions. Accessions of the longest-fruited cultivar-group, Cocozelle, radiated bidirectionally, indicating independent selection events for long fruits in subsp. pepo probably driven by a common desire to consume the young fruits. Among the accessions tested, there was no evidence for crossing between subspecies after domestication.     

Fractionation and electrophoretic patterns of seed protein of Opuntia genus. A preliminary survey as a tool for accession differentiation and taxonomy

At present, little is known about Opuntia seed proteins and their contribution to the characterization and taxonomy of genotypes belong to this genus. The variation among 102 accessions of Mexican Opuntia was studied using electrophoretic patterns by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) of their seed total proteins (STPs) and seed storage proteins (SSPs). Albumins and globulins were the most abundant protein fractions, with contents varied from 2.6 to 11.9 mg/mL and 2.6–9.5 mg/mL, respectively. These were followed by glutelins (2.3–8.5 mg/mL) and prolamins as the lowest (1.1–7.9 mg/mL) of the four protein factions. On the other hand, STPs content varied between 1.13 and 7.12 mg/mL. Regardless of variations in protein content estimated in seeds, the electrophoretic patterns of STPs and SSPs, as outcome of their SDS–PAGE, were not so variable. Furthermore, the individual analysis of each STPs or the SSPs analyses, separately, were not enough to discriminate all accessions, since it was necessary to combine the data resulting from all protein profiles together to differentiate all Opuntia genotypes. The UPGMA analysis indicated that there is no separation between accessions of species of the prickly pear (sweet fruits) and “xoconostle” (acidic fruits), even though the latter were grouped together. Based on biochemical markers analyzed herein, the need for revision of taxonomic assignment of genotypes belonging to the genus Opuntia is suggested.     

Seed storage protein variation in Arachis species.

Seventy-two accessions, representing 22 species from sections Arachis, Erectoides, Extranervosae, and Triseminalae of the genus Arachis, were screened for seed storage protein polymorphism. Variation was detected between sections, between genome types, between species, and in some cases between different accessions of the same species or different seeds of the same accession. Arachis duranensis and one accession of A. cardenasii were found to have identical protein patterns. The greatest dissimilarity was found between species of the section Extranervosae and species of the section Triseminalae. Those of section Erectoides showed much similarity with some species of section Arachis. Protein polymorphism was shown to distinguish the two subspecies of A. hypogaea (fastigiata and hypogaea) in 27 of 28 cases. The seed protein profile of A. monticola was a combination of seed protein profiles from the two A. hypogaea subspecies. The relatedness between the various species was calculated and those that had the greatest similarity with A. hypogaea were A. spegazzinii and A. batizocoi.     

RFLP-based assay of Sorghum bicolor (L.) Moench genetic diversity

Sixty-two single-copy sorghum DNA clones were used to compare restriction fragment patterns of 53 sorghum accessions from Africa, Asia and the United States. Included were accessions from five morphological races of the cultivated subspecies bicolor, and four races of the wild subspecies verticilliflorum. From two to twelve alleles were detected with each probe. There was greater nuclear diversity in the wild subspecies (255 alleles in ten accessions) than in the domestic accessions (236 alleles in 37 accessions). Overall, 204 of the 340 alleles (60%) that were detected occurred in both subspecies. Phylogenetic analysis using parsimony separated the subspecies into separate clusters, with one group of intermediate accessions. Though exceptions were common, especially for the race bicolor, accessions classified as the same morphological race tended to group together on the basis of RFLP similarities. Selection for traits such as forage quality may have led to accessions genetically more similar to other races being classified as bicolors, which have a loose, small-grained panicle similar to wild races. Population statistics, calculated using four nuclear and four cytoplasmic probes that detect two alleles each, revealed a low but significant amount of heterozygosity, and showed little differentiation in alleles in the wild and cultivated subspecies. Outcrossing with foreign pollen appears to have been more important than migration via seed dispersal as a mechanism for gene flow between the wild and domestic accessions included in this study.     

Direct amplification of minisatellite-region DNA with VNTR core sequences in the genus Oryza

 A polymerase chain reaction (PCR) application, involving the directed amplification of minisatellite-region DNA (DAMD) with several minisatellite core sequences as primers, was used to detect genetic variation in 17 species of the genus Oryza and several rice cultivars (O. sativa L.). The electrophoretic analysis of DAMD-PCR products showed high levels of variation between different species and little variation between different cultivars of O. sativa. Polymorphisms were also found between accessions within a species, and between individual plants within an accession of several wild species. The DAMD-PCR yielded genome-specific banding patterns for the species studied. Several DAMD-PCR-generated DNA fragments were cloned and characterized. One clone was capable of detecting multiple fragments and revealed individual-specific hybridization banding patterns using genomic DNA from wild species as well as rice cultivars. A second clone detected only a single polymorphic locus, while a third clone expressed a strong genome specificity by Southern analysis. The results demonstrated that DAMD-PCR is potentially useful for species and genome identification in Oryza. The DAMD-PCR technique also allows for the isolation of informative molecular probes to be utilized in DNA fingerprinting and genome identification in rice. Received: 1 October 1996 / Accepted: 25 April 1997     

Overexpression of the rFCA RNA Recognition Motif Affects Morphologies Modifications in Rice (Oryza sativa L.)

RNA recognition motifs as important regulators of gene expression are highly conserved in animals and plants. The FCA floral promotion gene in Arabidopsis encodes a protein, containing two RNA recognition motifs (RRM) and a WW protein interaction domain. Here we isolated FCA cDNA from rice. FCA in rice (rFCA) was homologous to FCA-gamma of Arabidopsis and contained conserved domains. To investigate the function of RRM domain, fragment RRM1 and RRM2 of rFCA were introduced into rice subspecies Oryza sativa L. subsp. Indica var. 9311 and another rice subspecies Oryza sativa L. subsp. Japonica var. zhonghua11 transformation. Two transgenic lines exhibited similar phenotypes, flowering time delay, seed size and cell volume of transgenic plants was increased. These results showed that constitutive expression of RRMs could regulate cellular size. The patterns of overexpression of two RRM domains and their similar morphologies indicate they may play a same role.     

Genetic diversity study of some medicinal plant accessions belong to Apiaceae family based on seed storage proteins patterns

Cumin (Cuminum cyminum L.), Fennel (Foeniculum vulgare L.) and Longleaf (Falcaria vulgaris Bernh) that all belong to Apiaceae family as medicinal plants are very important in many countries. Study of genetic diversity for medicinal plant is important for researches in future. One of the methods to evaluate plant genetic diversity and classification of them is the electrophoresis of seed storage proteins. This research was conducted in order to evaluate seed protein variability in different Iranian Cumin, Fennel and Longleaf accessions and grouping them based on these proteins as a biochemical marker. For this purpose, the samples were first powdered in liquid nitrogen and seed protein was extracted with extraction buffer. Then total soluble proteins were resolved on 12.5?% sodium dodecyl sulphate polyacrylamide gel electrophoresis gels. The electrophoretic protein pattern showed 38 bands that were low polymorphism among the accessions. The result of cluster analysis showed that the accessions were classified in three groups (all 29 Cumin accessions in the first group, three Fennel ecotypes in second group and three Longleaf accessions in the last one).     

Inferring population structure and genetic diversity of broad range of wild diploid alfalfa (Medicago sativa L.) accessions using SSR markers

Diversity analyses in alfalfa have mainly evaluated genetic relationships of cultivated germplasm, with little known about variation in diploid germplasm in the M. sativa–falcata complex. A collection of 374 individual genotypes derived from 120 unimproved diploid accessions from the National Plant Germplasm System, including M. sativa subsp. caerulea, falcata, and hemicycla, were evaluated with 89 polymorphic SSR loci in order to estimate genetic diversity, infer the genetic bases of current morphology-based taxonomy, and determine population structure. Diploid alfalfa is highly variable. A model-based clustering analysis of the genomic data identified two clearly discrete subpopulations, corresponding to the morphologically defined subspecies falcata and caerulea, with evidence of the hybrid nature of the subspecies hemicycla based on genome composition. Two distinct subpopulations exist within each subsp. caerulea and subsp. falcata. The distinction of caerulea was based on geographical distribution. The two falcata groups were separated based on ecogeography. The results show that taxonomic relationships based on morphology are reflected in the genetic marker data with some exceptions, and that clear distinctions among subspecies are evident at the diploid level. This research provides a baseline from which to systematically evaluate variability in tetraploid alfalfa and serves as a starting point for exploring diploid alfalfa for genetic and breeding experiments.     

Numerical morphological analysis of Lettuce cultivars and species (Lactuca sect.Lactuca,Asteraceae)

L. sativa L. cultivars were compared morphologically with accessions ofL. saligna L.,L. serriola L., andL. virosa L. in order to define the infra- and interspecific variation. Multivariate analysis (principal component analysis) distinguished four groups corresponding with the four species. Infraspecific variation (e.g., colour, leaf shape) withinL. sativa is the largest, because breeding has caused a large variation in vegetative features; infraspecific variation withinL. serriola is also large. Three plants of one accession were placed betweenL. sativa andL. serriola because they showed morphological characteristics of both species. They are still classified asL. sativa. The morphological differences betweenL. sativa andL. serriola are too large to consider these two as one species. The descent of the cultivar groups and the four species is described.     

Experimental studies of adaptation in Clarkia xantiana. I. Sources of trait variation across a subspecies border

Abstract Both genetic differentiation and phenotypic plasticity might be expected to affect the location of geographic range limits. Co‐gradient variation (CoGV), plasticity that is congruent with genetic differentiation, may enhance performance at range margins, whereas its opposite, counter‐gradient variation (CnGV) may hinder performance. Here we report findings of reciprocal transplant experiments intended to tease apart the roles of differentiation and plasticity in producing phenotypic variation across a geographic border between two plant subspecies. Clarkia xantiana ssp. xantiana and C. xantiana ssp. parviflora are California‐endemic annuals that replace each other along a west‐east gradient of declining precipitation. We analyzed variation in floral traits, phenological traits, and vegetative morphological and developmental traits by sowing seeds of 18 populations (six of ssp. xantiana and 12 of ssp. parviflora) at three sites (one in each subspecies' exclusive range and one in the subspecies' contact zone), in two growing seasons (an exceptionally wet El Niño winter and a much drier La Niña winter). Significant genetic differences between subspecies appeared in 11 of 12 traits, and differences were of the same sign as in nature. These findings are consistent with the hypothesis that selection is responsible for subspecies differences. Geographic variation within subspecies over part of the spatial gradient mirrored between‐subspecies differences present at a larger scale. All traits showed significant plasticity in response to spatial and temporal environmental variation. Plasticity patterns ranged from spatial and temporal CoGV (e.g., in node of first flower), to spatial CnGV (e.g., in flowering time), to patterns that were neither CoGV nor CnGV (the majority of traits). Instances of CoGV may reflect adaptive plasticity and may serve to increase performance under year‐to‐year environmental variation and at sites near the subspecies border. However, the presence of spatial CnGV in some critical traits suggests that subspecies ranges may also be constrained by patterns of plasticity.