Mycorrhizal and rhizobial interactions influence model grassland plant community structure and productivity.

Arbuscular mycorrhizal (AM) fungi and rhizobium are likely important drivers of plant coexistence and grassland productivity due to complementary roles in supplying limiting nutrients. However, the interactive effects of mycorrhizal and rhizobial associations on plant community productivity and competitive dynamics remain unclear. To address this, we conducted a greenhouse experiment to determine the influences of these key microbial functional groups on communities comprising three plant species by comparing plant communities grown with or without each symbiont. We also utilized N-fertilization and clipping treatments to explore potential shifts in mycorrhizal and rhizobial benefits across abiotic and biotic conditions. Our research suggests AM fungi and rhizobium co-inoculation was strongly facilitative for plant community productivity and legume (Medicago sativa) growth and nodulation. Plant competitiveness shifted in the presence of AM fungi and rhizobium, favoring M. sativa over a neighboring C4 grass (Andropogon gerardii) and C3 forb (Ratibida pinnata). This may be due to rhizobial symbiosis as well as the relatively greater mycorrhizal growth response of M. sativa, compared to the other model plants. Clipping and N-fertilization altered relative costs and benefits of both symbioses, presumably by altering host-plant nitrogen and carbon dynamics, leading to a relative decrease in mycorrhizal responsiveness and proportional biomass of M. sativa relative to the total biomass of the entire plant community, with a concomitant relative increase in A. gerardii and R. pinnata proportional biomass. Our results demonstrate a strong influence of both microbial symbioses on host-plant competitiveness and community dynamics across clipping and N-fertilization treatments, suggesting the symbiotic rhizosphere community is critical for legume establishment in grasslands.

Resource islands of Salix cupularis facilitating seedling emergence of the companion herbs in the restoration process of desertified alpine meadow, the Tibetan Plateau.

Salix cupularis is a common shrub for ecological restoration of the desertified alpine meadow on the Tibetan Plateau. However, the effect of S. cupularis on spatial heterogeneity of soil resources (i.e., resource islands effect) has not been systematically evaluated, and the influence of shrub patches on the rehabilitation of understory herbs has also been unknown. In this study, we randomly selected S. cupularis individuals in the early restoration stage of desertified alpine meadow, where the three native forages (Elymus nutans, Elymus sibiricus and Festuca sinensis) were sown at different microsites around S. cupularis to explore the effects of S. cupularis on soil resources and emergence rates of the native forages. The results showed that S. cupularis significantly increased SWC (soil water content), C (carbon) and N (nitrogen) nutrients (p < 0.01) and enzyme activities (p < 0.05) under canopy compared with the bare land, and the improvement performed better in the topsoil (0-5 cm) than in the subtop-soil (5-15 cm). Moreover, the soil properties were affected significantly by microsites around S. cupularis, resulting in regular changes of SWC, nutrients and enzyme activities in different microsites (Shrub center > Middle of canopy radius > Bare land). In addition, there are significant regression relationships between emergence rates and enriching soil water, C and N nutrients, so the emergence rates of native forages under canopy may be improved significantly with the enriched soil resources, especially for E. nutans. As a result, S. cupularis is a suitable pioneer shrub for the vegetation restoration of desertified alpine meadow on the Tibetan Plateau, because it could not only shape the enrichment of soil resources under canopy, but also facilitate emergence of companion forages in the process of vegetation restoration.

The complete mitochondrial genome of Cynops cyanurus cyanurus (Caudata: Salamandridae) and its phylogenetics analysis.

The complete mitochondrial of Cynops cyanurus cyanurus was determined by using Sanger sequencing and the mitogenome size of C. c. cyanurus was 16,465 bp. It contained 13 protein-coding genes, 22 tRNAs, 2 rRNAs, 1 control region (D-loop) and a non-coding region (NC). In addition, the phylogenetic tree shows that C. c. cyanurus has the closest relationship with C. c. chuxiongensis. Hoping this study can improve our understanding of the species evolutionary relationship of Cynops.

The complete mitogenome of the large toothed toad, Oreolalax major (Anura: Megophryidae) with phylogenetic analysis.

The complete mitochondrial genome of the Oreolalax major (17,786 bp long) was obtained in this study. It includes 13 protein-coding genes (PCG), two ribosomal RNA (rRNA) genes, and 23 transfer RNA (tRNA) genes (GenBank accession number MN803320). The phylogenetic tree indicates that the O. major is closely related to the O. xiangchengensis.

The near complete mitochondrial genome of Oreolalax schmidti (Anura: Megophryidae).

We newly obtained the near complete mitochondrial genome of Oreolalax schmidti (18,481bp) by using polymerase chain reaction (PCR) in this study. It includes 13 protein-coding genes (PCG), two ribosomal RNA (rRNA) genes, and 23 transfer RNA (tRNA) genes. The phylogenetic tree indicates that the Oreolalax schmidti is closely related to the O. lichuanensis. This report will help the further studies of Oreolalax species classification and source protection.

The complete mitochondrial genome of Cynops cyanurus chuxiongensis (Caudata: Salamandridae).

Cynops cyanurus chuxiongensis is distributed in Yunnan plateau. In this paper, we sequenced and determined the complete mitochondrial genome of C. c. chuxiongensis. The assembled mitogenome is 16,465 bp in length and encoding 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA genes (12S rRNA and 16S rRNA), and one control region (D-loop). The phylogenetic trees indicated C. c. chuxiongensis (KY418068) has the closest relationship with C. orientalis + C. orphicus, and clustered within the clade of genus Cynops.