Revelation of genetic diversity and structure of wild Elymus excelsus (Poaceae: Triticeae) collection from western China by SSR markers

Abstract

Hosting unique and important plant germplasms, the Qinghai-Tibet Plateau (QTP), as the third pole of the world, and Xinjiang, located in the centre of the Eurasian continent, are major distribution areas of perennial Triticeae grasses, especially the widespread Elymus species. Elymus excelsus Turcz. ex Griseb, a perennial forage grass with strong tolerance to environmental stresses, such as drought, cold and soil impoverishment, can be appropriately used for grassland establishment due to its high seed production. To provide basic information for collection, breeding strategies and utilization of E. excelsus germplasm, microsatellite markers (SSR) were employed in the present study to determine the genetic variation and population structure of 25 wild accessions of E. excelsus from Xinjiang (XJC) and the QTP, including Sichuan (SCC) and Gansu (GSC) of western China. Based on the 159 polymorphic bands amplified by 35 primer pairs developed from three related species, the average values of the polymorphic information content (PIC), marker index (MI), resolving power (Rp), Nei’s genetic diversity (H) and Shannon’s diversity index (I) of each pair of primers were 0.289, 1.348, 1.897, 0.301 and 0.459, respectively, validating that these SSR markers can also be used for the evaluation of genetic diversity of E. excelsus germplasms, and demonstrating the superior versatility of EST-SSR vs. G-SSR. We found a relatively moderate differentiation (Fst = 0.151) among the XJC, SCC and GSC geo-groups, and it is worth noting that, the intra-group genetic diversity of the SCC group (He = 0.197) was greater than that of the GSC (He = 0.176) and XJC (He = 0.148) groups. Both the Unweighted Pair Group Method with Arithmetic (UPGMA) clustering and principal coordinates analysis (PCoA) divided the 25 accessions into three groups, whereas the Bayesian STRUCTURE analysis suggested that E. excelsus accessions fell into four main clusters. Besides, this study suggested that geographical distance and environmental variables (annual mean precipitation and average precipitation in growing seasons), especially for QTP accessions, should be combined to explain the population genetic differentiation among the divergent geographical regions. These data provided comprehensive information about these valuable E. excelsus germplasm resources for the protection and collection of germplasms and for breeding strategies in areas of Xinjiang and QTP in western China.

Full-length transcriptome sequencing analysis and characterization, development and validation of microsatellite markers in Kengyilia melanthera

“…The SSR markers developed in this study showed a high level of transferability among the related species. This phenomenon was also found in many other species, such as E. sibiricus (Zhang et al, 2019), Agropyron cristatum (Ren et al, 2016), and E. excelsus (Xiong et al, 2019). In terms of geographical distribution, K. alatavica and K. Batalinii were all from Central Asia, while K. Mutica, K. rigidula, and K. melanthera were mainly distributed in the QTP (Yen and Yang, 2020), which was consistent with the results of clustering.…”

Molecular Phylogeography and Intraspecific Divergences in Siberian Wildrye (Elymus sibiricus L.) Wild Populations in China, Inferred From Chloroplast DNA Sequence and cpSSR Markers

“…On the other hand, isolation by environment (IBE), which relates to habitat heterogeneity, is also believed to be responsible for population divergence. In previous studies, IBD or IBE patterns were found in several Elymus species, such as E. tangutorum ( r = 0.312, P = 0.001) ( Wu et al, 2019 ), E. nutans ( r = 0.433, P = 0.010) ( Chen et al, 2013 ), E. excelsus (r = 0.202, P < 0.01) ( Xiong et al, 2019 ), and E. athericus (r = 0.095, P = 0.04) ( Bockelmann et al, 2003 ). Considering the self-pollination and vegetative propagation character of E. sibiricus , as well as the matrilineal inheritance of chloroplast DNA, there is expected to be no difference between QTP and its propagated population, namely, XJ and NC.…”

Genetic diversity and population structure of Robinia pseudoacacia from six improved variety bases in China as revealed by simple sequence repeat markers

“…The value was higher than that of the R. pseudoacacia samples from 10 main planting districts in China using AFLP and ISSR markers (Huo et al 2009;Sun et al 2009). The higher I value may be related to use the different types of molecular markers and/or the sources of materials (Lu et al 2020;Xiong et al 2019). Sequentially, 12 EST-SSR markers to evaluate 123 black locust cultivars in China were compared with those in our study, showing lower values for N a , N e and I in our populations (Dong et al 2019a, b).…”