Long-term irrational fertilizer inputs affect soil nutrients conditions in the agro-pastoral ecotone of North China. However, the mechanisms by which biotic and abiotic factors are affected by different fertilizer types remain unclear. A 16-year, long-term fertilization experiment was conducted to explore how soil physicochemical properties and microbial communities respond to different fertilizer types at an experimental site in North China. The key environmental factors that drove changes in soil microbial communities were also determined. In September 2019, soils were collected from plots of four fertilizer treatments: 1) non-fertilization control (CK), 2) chemical fertilization only (CF), 3) organic manure fertilization only (M), and 4) chemical fertilization plus organic manure (CFM). Compared with CK, soil organic matter, total nitrogen, available nitrogen, available phosphorus, and available potassium contents were higher in M and CFM, whereas soil pH was significantly lower in CF. Abundances of dominant soil bacterial phyla Proteobacteria, Bacteroidetes, and Gemmatimonadetes were higher in M and CFM than CK. Abundances of dominant soil fungal phyla Ascomycota was lower in CFM than in other treatments. The pathogenic fungi Fusarium, Paramyrothecium, Cladosporium, and Alternaria had the highest abundances in CK and CF, whereas abundances of the beneficial fungi Mortierella were significantly higher in M and CFM than in CF and CK. According to partial least squares path modeling, differences in fertilizer types had direct positive effects on fungal communities but little effect on bacterial communities. Overall, CFM maintained higher soil fertility and a healthy ecosystem because it increased beneficial microorganisms and inhibited pathogenic microorganisms, whereas CF increased the risk of crop infection with soil-borne diseases. The study provided a better understanding of how long-term fertilization affects microbial community composition and their associated ecosystem functions.

The yellow nutsedge (Cyperus esculentus L. 1753) is an unconventional oil plant with oil-rich tubers, and a potential alternative for traditional oil crops. Here, we reported the first high-quality and chromosome-level genome assembly of the yellow nutsedge generated by combining PacBio HiFi long reads, Novaseq short reads, and Hi-C data. The final genome size is 225.6 Mb with an N50 of 4.3 Mb. More than 222.9 Mb scaffolds were anchored to 54 pseudochromosomes with a BUSCO score of 96.0%. We identified 76.5 Mb (33.9%) repetitive sequences across the genome. A total of 23,613 protein-coding genes were predicted in this genome, of which 22,847 (96.8%) were functionally annotated. A whole-genome duplication event was found after the divergence of Carex littledalei and Rhynchospora breviuscula, indicating the rich genetic resources of this species for adaptive evolution. Several significantly enriched GO terms were related to invasiveness of the yellow nutsedge, which may explain its plastic adaptability. In addition, several enriched Kyoto Encyclopedia of Genes and Genomes pathways and expanded gene families were closely related with substances in tubers, partially explaining the genomic basis of characteristics of this oil-rich tuber.

Flax is an economic crop with a long history. It is grown worldwide and is mainly used for edible oil, industry, and textiles. Here, we reported a high-quality genome assembly for “Neiya No. 9”, a popular variety widely grown in China. Combining PacBio long reads, Hi-C sequencing, and a genetic map reported previously, a genome assembly of 473.55 Mb was constructed, which covers ~94.7% of the flax genome. These sequences were anchored onto 15 chromosomes. The N50 lengths of the contig and scaffold were 0.91 Mb and 31.72 Mb, respectively. A total of 32,786 protein-coding genes were annotated, and 95.9% of complete BUSCOs were found. Through morphological and cytological observation, the male sterility of flax was considered dominant nuclear sterility. Through GWAS analysis, the gene LUSG00017705 (cysteine synthase gene) was found to be closest to the most significant SNP, and the expression level of this gene was significantly lower in male sterile plants than in fertile plants. Among the significant SNPs identified in the GWAS analysis, only two were located in the coding region, and these two SNPs caused changes in the protein encoded by LUSG00017565 (cysteine protease gene). It was speculated that these two genes may be related to male sterility in flax. This is the first time the molecular mechanism of male sterility in flax has been reported. The high-quality genome assembly and the male sterility genes revealed, provided a solid foundation for flax breeding.