Analysis of the genetic diversity of the coastal and island endangered plant species Elaeagnus macrophylla via conserved DNA-derived polymorphism marker

Phylogenetic Analysis of Elaeagnus L. in China: A Basis for Genetic Improvement of a Berry Crop

Elaeagnus L. is found in wild or grown as ornamental plants and is increasingly regarded as underutilized berry shrubs by breeders. This genus has cosmopolitan distribution with various species widely distributed in China, Europe, the United States, and Canada. Interspecific hybrids, which have been reported several times, have attracted intense interest from plant breeders attempting to develop a fruit crop of Elaeagnus. Orthogonal projections to latent structures discriminant analysis (OPLS-DA) is a powerful statistical modeling tool that provides insights into separations between experimental groups. In this study, the molecular phylogeny of Elaeagnus species was first discussed using the ITS and matK sequences for guiding the construction of a genetic basis pool. A morphological OPLS-DA clustering model based on the genetic divergence was also constructed for the first time, which effectively realized the morphological grouping of Chinese Elaeagnus species. The results showed that a total of 10 wild species widely distributed in China have the potential to develop fruit crops. Particularly, Elaeagnus conferta has the potential to provide a founder species with a large fruit size, while Elaeagnus Gonyanthes has the potential to provide important genetic resources with long pedicel. Elaeagnus lanceolata and Elaeagnus delavayi could be used to domesticate hybrids without spines, and the other five climbing shrubs could be used to develop high-yield crown-type commercial cultivars for automated field management. The top five contributing morphological traits affecting the current clustering model were V9 (flower color), V1 (flowering), V5 (evergreen or deciduous), V3 (leaf size), and V2 (fruiting). Furthermore, the grouping analysis indicated that the V9 was the most important factor affecting morphological clustering. Thereafter, the temporally calibrated phylogeny inferred from the matK sequence was used to reconstruct the origin and evolution of the genus Elaeagnus, and the results inferred an interesting geographic distribution pattern and potential cross-species interactions of Elaeagnus species at low latitudes in China. Our study also highlighted dispersal pattern investigation and genetic background analysis to improve future practices and policies related to species introduction of genetic basis pool.

The Development of New Species-Specific Molecular Markers Based on 5S rDNA in Elaeagnus L. Species

The Elaeagnus L. species are trees and bushes that mainly grow in temperate zones of Western Europe; Minor, Central, and Southeast Asia; the Far East; and North America. Some species are used as fruit or ornamental plants and have economic value. Problems with the identification of species in the Elaeagnus genus by molecular genetical methods arise in the study of populations, systematics, breeding, and other areas of plant science and practice. Recently, the polymorphism of 5S ribosomal DNA non-transcribed spacers (5S rDNA NTSs) in Elaeagnaceae Adans. has been described. The results were used in our study as a basis for development of new species-specific molecular markers for some members of the Elaeagnus genus. The author's method was applied for finding regions that were potentially applicable for species-specific primer design. As a result, some species-specific molecular markers were developed for Elaeagnus angustifolia L., E. commutata Bernh., E. pungens Thunb., and E. multiflora Thunb. These markers were tested in a range of samples and showed the presence of amplified fragments in lanes of the marked species only. Samples of other species showed no amplifications. Thus, the developed markers may be useful for the species identification of the studied Elaeagnus plants in botanical, dendrological, and genetic research (especially in a leafless period of year), as well as in breeding and hybridization experiments.

The genetic diversity and population structure of two endemic Amazonian quillwort (Isoetes L.) species

Background

Two endemic lycophyte species Isoetes cangae and Isoetes serracarajensis have been recently described in the State of Pará in the Amazon forest located in northern Brazil. Isoetes L. has survived through three mass extinctions. Plants are considered small-sized, heterosporous, and can display a great diversity of physiological adaptations to different environments. Thus, the current study aimed to estimate the genetic variation of the populations of I. cangae and I. serracarajensis to generate information about their different mechanisms for survival at the same geographical location that could point to different reproductive, adaptative and dispersal strategies and should be considered for effective conservation strategies.

Methods

The genetic diversity and population structure of I. cangae and I. serracarajensis were investigated using Inter Simple Sequence Repeat (ISSR) molecular markers. Total genomic DNA was isolated, and the genetic diversity parameters were calculated.

Results

The sixteen primers produced 115 reproducible bands, 87% of which were polymorphic. A high level of polymorphic loci (81.74% and 68.48%) and a high Shannon index (Sh = 0.376 and 0.289) were observed for I. cangae and I. serracarajensis, respectively. The coefficient of genetic differentiation between population areas (G_ST) showed a higher value in I. serracarajensis (0.5440). Gene flow was higher in I. cangae (1.715) and lower in I. serracarajensis populations (0.419). Overall, the results further show that I. serracarajensis and I. cangae are two species with considerable genetic variation and that these differences may reflect their habitats and modes of reproduction. These results should be considered in the development of effective conservation strategies for both species.