Microsatellites are often highly variable and abundant in most complex genomes, therefore are widely used in population genetic studies. In this study, twelve polymorphic microsatellite loci were isolated and characterized for the Achnatherum inebrians, a plant abundant in grasslands of Northwest China. Characterization of 24 A. inebrians individuals form four geographically distant populations (Gansu, Qinghai, Xinjiang and Inner Mongolia provinces) showed moderate to high allelic diversity ranging from 3 to 13 alleles per locus, and the expected heterozygosity ranging from 0.41 to 0.67. No evidence of linkage disequilibrium was found for any locus pairwise comparisons. The markers described here will be useful for investigating the genetic diversity, genetic structure and gene flow of this species.

Achnatherum sibiricum is a threaten and toxic perennial bunchgrass mainly in the north of China. We developed 11 polymorphic microsatellite loci from A. sibiricum by combining biotin capture method. After validating and scoring, these loci were polymorphic in a test population with the range of alleles from four to 13 per locus. The observed and expected heterozygosities ranged from 0.1649 to 0.5624 and from 0.3071 to 0.8826, respectively. All 11 microsatellite markers were in Hardy– Weinberg equilibrium. These polymorphic microsatellites will be useful for genetic diversity analysis and population structure construction for A. sibiricum.

The effects of cadmium on biomass production and growth parameters of drunken horse grass(Achnatherum inebrians) over an 8-week period were determined in a controlled-environment experiment.Changes were determined for relative water content, anti-oxidative enzymes (i.e., catalase (CAT),superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX)) and for H2O2 content,as well as levels of proline, malondialdehyde (MDA), and chlorophylls “a” and “b” present within leaves infected with Neotyphodium gansuense vs. non-infected controls. observations began 4 weeks after addition of CdCl2 (0, 50, 100 and 200 M) to the nutrient solution. Under high concentrations (100 and200 M) of CdCl2, endophyte-infected plants produced more biomass and had higher values for plantheight and tiller number compared to non-infected controls, but there was no significant difference (P > 0.05) under 0 and 50 M CdCl2. Anti-oxidative enzyme activities, H2O2 concentration, and chlorophylls“a” and “b” levels increased, but proline and malondialdehyde content declined in the infected plants vs. non-infected plants under high (100 and 200 M) concentrations of CdCl2. There was no significant difference (P>0.05) under 0 and 50 M CdCl2. Endophyte infection was concluded to be of benefit to the growth and anti-oxidative mechanisms within A. inebrians under high concentrations exposures to CdCl2.

Several species of Achnatherum (grass tribe Stipeae) and Melica (tribe Meliceae) typically are infected by nonpathogenic, seed-transmissible fungi with characteristics of Neotyphodium species (anamorphic Clavicipitaceae). Molecular phylogenetic studies clearly have distinguished the endophytes from Achnatherum inebrians (from Xinjiang Province, China), A. robustum and A. eminens (both from North America) and indicate that the A. inebrians endophyte comprises a unique nonhybrid lineage within the Epichloe and Neotyphodium phylogeny, whereas the endophytes of A. robustum, and A. eminens are hybrids with multiple Epichloe species (holomorphic Clavicipitaceae) as ancestors. Likewise distinct hybrid origins are indicated for Neotyphodium species from the European Melica species, M. ciliata and M. transsilvanica, the South African species M. decumbens and M. racemosa, and the South American species M. stuckertii. Neotyphodium species have been described from A. inebrians from Gansu Province, China, (N. gansuense), A. eminens (N. chisosum), M. stuckertii (N. tembladerae) and the South African Melica species (N. melicicola). However the endophytes from A. robustum and the European Melica species have not been described and the phylogenetic relationships of N. gansuense have not been investigated. Here we report a comprehensive study of morphological features and phylogenetic analyses of b -tubulin and actin gene sequences on an expanded collection of endophytes from the Stipeae and Meliceae. These data provide a firm foundation for the description of two new Neotyphodium species, N. guerinii from M. ciliata and M. transsilvanica, and N. funkii from A. robustum. We also propose the new variety, N. gansuense var. inebrians for endophytes of A. inebrians from Xinjiang Province, which are morphologically and phylogenetically distinct from, yet clearly related to, N. gansuense from Gansu Province.

Root-invading fungi of milk vetch (Astragalus adsurgens) at different growth stages grown in three ages of sown pasture soil were studiedin Huanxian county, Gansu province, China. Pathogenicity was tested by seed and soil inoculation. A total of 44 fungi were isolated from milkvetch roots, 32 from the roots of field plants and 37 from the roots of potted seedlings. The total percentage of root segments yielding fungalcolonies increased with age of plants; they were 70.5%, 82.3% and 97.8% in 1-, 3-, and 5-year-old plant roots, respectively, differences thatwere significant (P<0.05). The frequency of isolation from roots of plants at re-greening, branching, flowering and yellowing growth stageswere 62.0%, 95.3%, 93.0% and 83.7%, respectively. The total percentage of root segments yielding fungal colonies from 3-, 6-and 12-weekoldpotted seedlings were 21.8%, 44.7% and 32.0%, respectively, differences that were also significant (P<0.05). Seedlings were easilyinfected and symptoms of damping-off disease were common in seedlings younger than 3-week-old. Of the 44 fungi isolated and tested forpathogenicity by seed inoculation, 19 decreased seed germination rate, 12 decreased seedling shoot length, and 22 decreased seedling rootlength. Fusarium solani, F. oxysporum, F. chlamydosporum, F. avenaceum and Gliocladium roseum were strongly pathogenic to milk vetch. Insoil inoculation tests, these same fungi (except for F. chlamydosporum) decreased seedling root dry matter production significantly(P<0.05), but seed germination and seedling survival were not affected by any of these fungi.