Multi-omics of Circular RNAs and Their Responses to Hormones in Moso Bamboo (Phyllostachys edulis).

Circular RNAs (circRNAs) are endogenous non-coding RNAs with covalently closed structures, which have important functions in plants. However, their biogenesis, degradation, and function upon treatment with gibberellins (GAs) and auxins (1-naphthaleneacetic acid, NAA) remain unknown. Here, we systematically identified and characterized the expression patterns, evolutionary conservation, genomic features, and internal structures of circRNAs using RNase R-treated libraries from moso bamboo (Phyllostachys edulis) seedlings. Moreover, we investigated the biogenesis of circRNAs dependent on both cis- and trans-regulation. We explored the function of circRNAs, including their roles in regulating microRNA (miRNA)-related genes and modulating the alternative splicing of their linear counterparts. Importantly, we developed a customized degradome sequencing approach to detect miRNA-mediated cleavage of circRNAs. Finally, we presented a comprehensive view of the participation of circRNAs in the regulation of hormone metabolism upon treatment of bamboo seedlings with GA and NAA. Collectively, our study provides insights into the biogenesis, function, and miRNA-mediated degradation of circRNAs in moso bamboo.

Single-cell Raman and functional gene analyses reveal microbial P solubilization in agriculture waste-modified soils.

Application of agricultural waste such as rapeseed meal (RM) is regarded as a sustainable way to improve soil phosphorus (P) availability by direct nutrient supply and stimulation of native phosphate-solubilizing microorganisms (PSMs) in soils. However, exploration of the in situ microbial P solubilizing function in soils remains a challenge. Here, by applying both phenotype-based single-cell Raman with D2O labeling (Raman-D2O) and genotype-based high-throughput chips targeting carbon, nitrogen and P (CNP) functional genes, the effect of RM application on microbial P solubilization in three typical farmland soils was investigated. The abundances of PSMs increased in two alkaline soils after RM application identified by single-cell Raman D2O. RM application reduced the diversity of bacterial communities and increased the abundance of a few bacteria with reported P solubilization function. Genotypic analysis indicated that RM addition generally increased the relative abundance of CNP functional genes. A correlation analysis of the abundance of active PSMs with the abundance of soil microbes or functional genes was carried out to decipher the linkage between the phenotype and genotype of PSMs. Myxococcota and C degradation genes were found to potentially contribute to the enhanced microbial P release following RM application. This work provides important new insights into the in situ function of soil PSMs. It will lead to better harnessing of agricultural waste to mobilize soil legacy P and mitigate the P crisis.

[Nitrification, Denitrification, and N2O Production Under Saline and Alkaline Conditions].

A sequencing biofilm batch reactor (SBBR) running continuously in an anaerobic/aerobic/anoxic (An/O/A) mode was adopted to study the characteristics of nitrification and denitrification process and nitrous oxide (N2O) production under high saline and alkaline conditions. Different carbon and nitrogen ratios (C/N) were also investigated. An influent C/N ratio of 5, 2, and 0 (control), achieved the following results:TN removal efficiency was (98.17±0.42)%, (65.78±2.47)%, and (44.08±0.27)%, respectively; total N2O production was (32.07±2.03) mg·L-1, (21.81±0.85) mg·L-1, and (17.32±0.95) mg·L-1, respectively; and the N2O conversion rate (i. e., the ratio of total N2O production to total nitrogen removal) was (29.75±0.93)%, (30.04±2.17)%, and (41.69±0.80)%, respectively. The nitrification process proceeded normally during the nitrite stage, and nitrite-oxidizing bacteria (NOB) were strongly inhibited under the high saline and alkaline conditions. Due to the inhibition of N2O reductase under these conditions, N2O production was higher during the heterotrophic denitrification process than during the ammonia oxidation process. With an increase in the carbon to nitrogen ratio, more carbon sources were available for denitrification meaning that the total nitrogen removal rate and N2O production were both increased. As the ratio of carbon to nitrogen was increased, the N2O conversion rate decreased, which may have been caused by electron competition among the nitrogen oxide reductases during the denitrification process; the higher the ratio of carbon to nitrogen, the weaker the electron competition. High-throughput sequencing indicated that ammonium-oxidizing bacteria (AOB) were enriched and NOB were almost entirely absent in the SBBR. Thauera, Azoarcus, and Gemmobacter were the dominant heterotrophic denitrifying bacteria identified in the system.