Image_1_Response of soil bacterial community to alpine wetland degradation in arid Central Asia.jpeg

A large number of studies have reported the importance of bacterial communities in ecosystems and their responses to soil degradation, but the response mechanism in arid alpine wetlands is still unclear. Here, the non-degraded (ND), slightly degraded (SD), and heavily degraded (HD) regions of Bayinbuluk alpine wetland were used to analyzed the diversity, structure and function of bacterial communities in three degraded wetlands using 16S rRNA. The results showed that with the increase of degradation degree, the content of soil moisture (SM) and available nitrogen (AN) decreased significantly, plant species richness and total vegetation coverage decreased significantly, Cyperaceae (Cy) coverage decreased significantly, and Gramineae (Gr) coverage increased significantly. Degradation did not significantly affect the diversity of the bacterial community, but changed the relative abundance of the community structure. Degradation significantly increased the relative abundance of Actinobacteria (ND: 3.95%; SD: 7.27%; HD: 23.97%) and Gemmatimonadetes (ND: 0.39%; SD: 2.17%; HD: 10.78%), while significantly reducing the relative abundance of Chloroflexi (ND: 13.92%; SD: 8.68%; HD: 3.55%) and Nitrospirae (ND: 6.18%; SD: 0.45%; HD: 2.32%). Degradation significantly reduced some of the potential functions in the bacterial community associated with the carbon (C), nitrogen (N) and sulfur (S) cycles, such as hydrocarbon degradation (ND: 25.00%; SD: 1.74%; HD: 6.59%), such as aerobic ammonia oxidation (ND: 5.96%; SD: 22.82%; HD: 4.55%), and dark sulfide oxidation (ND: 32.68%; SD: 0.37%; HD: 0.28%). Distance-based redundancy analysis (db-RDA) results showed that the bacteria community was significantly related to the TC (total carbon) and Gr (P < 0.05). The results of linear discriminant analysis effect size (LEfSe) analysis indicate significant enrichments of Alphaproteobacteria and Sphingomonas in the HD area. The vegetation communities and soil nutrients changed significantly with increasing soil degradation levels, and Sphingomonas could be used as potential biomarker of degraded alpine wetlands.</p

Residual N and P (as percentage of initial content) of fine and coarse roots from <i>E</i>. <i>oxyrrhynchum</i> and <i>S</i>. <i>santolinum</i> during the decomposition process under control (C), water (W), nitrogen (N), and water plus nitrogen addition (WN) treatments (experiment II).

<p>(A, E) fine and (B, F) coarse roots of <i>E</i>. <i>oxyrrhynchum</i>; (C, G) fine and (D, H) coarse roots of <i>S</i>. <i>santolinum</i>. Vertical bars represent standard errors (n <i>=</i> 3).</p

Seasonal changes in soil water content at the depth of 10 cm for control (C), water (W), nitrogen (N), and water plus nitrogen addition (WN) treatments (mean±SE).

<p>Seasonal changes in soil water content at the depth of 10 cm for control (C), water (W), nitrogen (N), and water plus nitrogen addition (WN) treatments (mean±SE).</p

Soil total N concentration at the depth of 20 cm for control (C), water (W), nitrogen (N), and water plus nitrogen addition (WN) treatments (mean±<i>SE</i>).

<p>* and ** represent differences between the N addition treatment and control at <i>P</i><0.05 and <i>P</i><0.01, respectively.</p

Residual N (as percentage of initial content) of <i>E</i>. <i>oxyrrhynchum</i> (A), <i>S</i>. <i>santolinum</i> (B), <i>S</i>. <i>subcrassa</i> (C), <i>P</i>. <i>communis</i> (D), <i>K</i>. <i>caspia</i> (E), and <i>N</i>. <i>sibirica</i> (F) during the decomposition process under control (C), water (W), nitrogen (N), and water plus nitrogen addition (WN) treatments (experiment I).

<p>Vertical bars represent standard errors (n = 3).</p

<i>F</i> and <i>P</i> values from four-way ANOVA for decomposition rate (k), residual N, and P (% of initial mass) during decomposition of root litter (experiment II), with species, root diameter, nitrogen addition, and water addition as main effects.

<p><i>F</i> and <i>P</i> values from four-way ANOVA for decomposition rate (k), residual N, and P (% of initial mass) during decomposition of root litter (experiment II), with species, root diameter, nitrogen addition, and water addition as main effects.</p

Initial N (A) and lignin (B) concentration of fine and coarse roots from <i>E</i>. <i>oxyrrhynchum</i> and <i>S</i>. <i>santolinum</i> in the second experiment (experiment II).

<p>* indicates significant differences between fine and coarse roots within each species (<i>P</i><0.05). Vertical bars represent standard errors (n = 3).</p

Residual mass for two diameter size classes of <i>E</i>. <i>oxyrrhynchum</i> (A) and <i>S</i>. <i>santolinum</i> (B) roots decomposing in the field over a period of 1.7 years (experiment II).

<p>Water and N addition treatments have been averaged by root size class within each species. ** indicate significant differences between fine and coarse roots within each species (<i>P</i><0.01). Vertical bars represent standard errors (n = 12). Insets show decomposition rates for fine and coarse roots of <i>E</i>. <i>oxyrrhynchum</i> and <i>S</i>. <i>santolinum</i>, respectively.</p

Data_Sheet_1_Biochar-mediated changes in the microbial communities of rhizosphere soil alter the architecture of maize roots.PDF

Aeolian sandy soil is a key resource for supporting food production on a global scale; however, the growth of crops in Aeolian sandy soil is often impaired due to its poor physical properties and lack of nutrients and organic matter. Biochar can be used to enhance the properties of Aeolian sandy soil and create an environment more suitable for crop growth, but the long-term effects of biochar on Aeolian sandy soil and microbial communities need to be clarified. Here, a field experiment was conducted in which biochar was applied to a maize (Zea mays L.) field in a single application at different rates: CK, 0 Mg ha−1; C1, 15.75 Mg ha−1; C2, 31.50 Mg ha−1; C3, 63.00 Mg ha−1; and C4, 126.00 Mg ha−1. After 7 years of continuous maize cropping, verify the relationship between root architecture and soil microbial communities under biochar application using a root scanner and 16S/ITS rRNA gene sequencing. The application of biochar promoted the growth of maize. Specifically, total root length, total root surface area, total root volume, and root biomass were 13.99–17.85, 2.52–4.69, 23.61–44.41, and 50.61–77.80% higher in treatments in which biochar was applied (C2, C3, and C4 treatments) compared with the control treatment, respectively. Biochar application increased the diversity of bacterial communities, the ACE index, and Chao 1 index of C1, C2, C3, and C4 treatments increased by 5.83–8.96 and 5.52–8.53%, respectively, compared with the control treatment, and significantly changed the structure of the of bacterial communities in rhizosphere soil. However, there was no significant change in the fungal community. The growth of maize roots was more influenced by rhizosphere bacteria and less by fungal community. A microbial co-occurrence network revealed strong associations among rhizosphere microorganisms. The core taxa (Module hubs taxa) of the bulk soil microbial co-occurrence network were closely related to the total length and total surface area of maize roots, and the core taxa (Connectors taxa) of the rhizosphere soil were closely related to total root length. Overall, our findings indicate that the application of biochar promotes the growth of maize roots in aeolian sandy soil through its effects on bacterial communities in rhizosphere soil.</p

Image3_The application of short and highly polymorphic microhaplotype loci in paternity testing and sibling testing of temperature-dependent degraded samples.PNG

Paternity testing and sibling testing become more complex and difficult when samples degrade. But the commonly used genetic markers (STR and SNP) cannot completely solve this problem due to some disadvantages. The novel genetic marker microhaplotype proposed by Kidd’s research group combines the advantages of STR and SNP and is expected to become a promising genetic marker for kinship testing in degraded samples. Therefore, in this study, we intended to select an appropriate number of highly polymorphic SNP-based microhaplotype loci, detect them by the next-generation sequencing technology, analyze their ability to detect degraded samples, calculate their forensic parameters based on the collected 96 unrelated individuals, and evaluate their effectiveness in paternity testing and sibling testing by simulating kinship relationship pairs, which were also compared to 15 STR loci. Finally, a short and highly polymorphic microhaplotype panel was developed, containing 36 highly polymorphic SNP-based microhaplotype loci with lengths smaller than 100 bp and Ae greater than 3.00, of which 29 microhaplotype loci could not reject the Hardy-Weinberg equilibrium and linkage equilibrium after the Bonferroni correction. The CPD and CPE of these 29 microhaplotype loci were 1-2.96E-26 and 1-5.45E-09, respectively. No allele dropout was observed in degraded samples incubated with 100°C hot water for 40min and 60min. According to the simulated kinship analysis, the effectiveness at the threshold of 4/−4 reached 98.39% for relationship parent-child vs. unrelated individuals, and the effectiveness at the threshold of 2/−2 for relationship full-sibling vs. unrelated individuals was 93.01%, which was greater than that of 15 STR loci (86.75% for relationship parent-child vs. unrelated individuals and 81.73% for relationship full-sibling vs. unrelated individuals). After combining our 29 microhaplotype loci with other 50 short and highly polymorphic microhaplotype loci, the effectiveness values at the threshold of 2/−2 were 82.42% and 90.89% for relationship half-sibling vs. unrelated individuals and full-sibling vs. half-sibling. The short and highly polymorphic microhaplotype panel we developed may be very useful for paternity testing and full sibling testing in degraded samples, and in combination with short and highly polymorphic microhaplotype loci reported by other researchers, may be helpful to analyze more distant kinship relationships.</p