Drought is the most important natural disaster affecting crop growth and development. Crop rhizosphere microorganisms can affect crop growth and development, enhance the effective utilization of nutrients, and resist adversity and hazards. In this paper, six spring wheat varieties were used as research material in the dry farming area of the western foot of the Greater Khingan Mountains, and two kinds of water control treatments were carried out: dry shed rain prevention (DT) and regulated water replenishment (CK). Phenotypic traits, including physiological and biochemical indices, drought resistance gene expression, soil enzyme activity, soil nutrient content, and the responses of potential functional bacteria and fungi under drought stress, were systematically analyzed. The results showed that compared with the control (CK), the leaf wilting, drooping, and yellowing of six spring wheat varieties were enhanced under drought (DT) treatment. The plant height, fresh weight (FW), dry weight (DW), net photosynthetic rate (Pn) and stomatal conductance (Gs), soil total nitrogen (TN), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), microbial biomass phosphorus (MBP), organic carbon (SOC), and soil alkaline phosphatase (S-ALP) contents were significantly decreased, among which, FW, Gs and MBC decreased by more than 7.84%, 17.43% and 11.31%, respectively. By contrast, the soil total phosphorus (TP), total potassium (TK), and soil catalase (S-CAT) contents were significantly increased (p < 0.05). TaWdreb2 and TaBADHb genes were highly expressed in T.D40, T.L36, and T.L33 and were expressed at low levels in T.N2, T.B12, and T.F5. Among them, the relative expression of the TaWdreb2 gene in T.L36 was significantly increased by 2.683 times compared with CK. Soil TN and TP are the most sensitive to drought stress and can be used as the characteristic values of drought stress. Based on this, a drought-tolerant variety (T.L36) and a drought-sensitive variety (T.B12) were selected to further analyze the changes in rhizosphere microorganisms. Drought treatment and cultivar differences significantly affected the composition of the rhizosphere microbial community. Drought caused a decrease in the complexity of the rhizosphere microbial network, and the structure of bacteria was more complex than that of fungi. The Shannon index and network modular number of bacteria in these varieties (T.L36) increased, with rich small-world network properties. Actinobacteria, Chloroflexi, Firmicutes, Basidiomycota, and Ascomycota were the dominant bacteria under drought treatment. The beneficial bacteria Bacillus, Penicillium, and Blastococcus were enriched in the rhizosphere of T.L36. Brevibacillus and Glycomyce were enriched in the rhizosphere of T.B12. In general, drought can inhibit the growth and development of spring wheat, and spring wheat can resist drought hazards by regulating the expression of drought-related genes, regulating physiological metabolites, and enriching beneficial microorganisms.

The recognition of pathogen effectors through the nucleotide-binding leucine-rich repeat receptor (NLR) family is an important component of plant immunity. In addition to typical domains such as TIR, CC, NBS, and LRR, NLR proteins also contain some atypical integrated domains (IDs), the roles of which are rarely investigated. Here, we carefully screened the soybean (Glycine max) genome and identified the IDs that appeared in the soybean TNL-like proteins. Our results show that multiple IDs (36) are widely present in soybean TNL-like proteins. A total of 27 Gm-TNL-ID genes (soybean TNL-like gene encoding ID) were cloned and their antiviral activity towards the soybean mosaic virus (SMV)/tobacco mosaic virus (TMV) was verified. Two resistance (R) genes, SRA2 (SMV resistance gene contains AAA_22 domain) and SRZ4 (SMV resistance gene contains zf-RVT domain), were identified to possess broad-spectrum resistance characteristics towards six viruses including SMV, TMV, plum pox virus (PPV), cabbage leaf curl virus (CaLCuV), barley stripe mosaic virus (BSMV), and tobacco rattle virus (TRV). The effects of Gm-TNL-ID^X (the domain of the Gm-TNL-ID gene after the TN domain) on the antiviral activity of a R protein SRC7^TN (we previously reported the TN domain of the soybean broad-spectrum resistance gene SRC7) were validated, and most of Gm-TNL-ID^X inhibits antiviral activity mediated by SRC7^TN, possibly through intramolecular interactions. Yeast-two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays showed that seven Gm-TNL-ID^X interacted with SMV-component proteins. Truncation analysis on a broad-spectrum antiviral protein SRZ4 indicated that SRZ4^TIR is sufficient to mediate antiviral activity against SMV. Soybean cDNA library screening on SRZ4 identified 48 interacting proteins. In summary, our results indicate that the integration of IDs in soybean is widespread and frequent. The NLR-ID toolkit we provide is expected to be valuable for elucidating the functions of atypical NLR proteins in the plant immune system and lay the foundation for the development of engineering NLR for plant-disease control in the future.

Rotation fallow is an effective way to overcome the obstacles associated with continuous cropping, being beneficial for the growth and development of crops. Soil micro-organisms are closely related to soil fertility, plant productivity, soil pathogenic bacteria, and crop health in agricultural ecosystems. To explore the effects of different rotation fallow modes on the diversity and functions of the soil bacterial community, a study was conducted in an arid area in the western foothills of the Greater Khingan Mountains. Using spring wheat variety Longmai 36 as the research material, this study systematically analyzed the changes and functional differences in soil physicochemical and biological characteristics, as well as microbial communities (endosphere, rhizosphere, and bulk soil) in spring wheat fields under five rotation fallow modes: Wheat²⁰¹⁶–Wheat²⁰¹⁷–Wheat²⁰¹⁸(WWW), Wheat²⁰¹⁶–Rape²⁰¹⁷–Fallow²⁰¹⁸(WRF), Wheat²⁰¹⁶–Potato²⁰¹⁷–Fallow²⁰¹⁸(WPF), Wheat²⁰¹⁶–Fallow²⁰¹⁷–Rape²⁰¹⁸(WFR), and Wheat²⁰¹⁶–Fallow²⁰¹⁷–Potato²⁰¹⁸ (WFP). The results indicate that, compared to WWW, the soil urease activity, microbial biomass nitrogen content, and microbial biomass phosphorus content were significantly increased in the WFP mode (p < 0.05). In particular, the soil moisture content, organic matter, and total potassium content were increased by 6.88%, 3.34%, and 25.57%, respectively. The Shannon index and chao1 index of bulk soil (BS) and rhizosphere (RS) bacteria were significantly higher than those of endosphere (ER) bacteria (p < 0.05). Both ecological niche and rotation fallow modes affected the relative abundance of dominant bacteria, and the relative abundance of beneficial bacteria, such as Bacteroidetes, Firmicutes, and Verrucomimicrobia, significantly increased in the rotation fallow modes. The complexity and stability of bacterial networks, and abundance of nitrogen-cycling-related functional taxa were significantly improved, while the abundance of pathogen-related functional taxa was significantly decreased. The differences in soil bacterial community structure were closely related to soil physicochemical properties. Compared to ER, BS and RS bacterial communities, which are more susceptible to soil physicochemical properties, and soil pH are key driving forces for bacterial community distribution. In summary, compared with continuous cropping, the rotation fallow mode is beneficial for conserving soil moisture and nutrients, stabilizing soil pH, (i.e., making the soil tend to be neutral), increasing the abundance of beneficial bacteria in the soil, enhancing the complexity and stability of microbial ecological networks, and increasing the abundance of nitrogen-cycling-related functional taxa, thus improving crop growth and development.

Conservation tillage has an influence on the cultivation and sustainable utilization of farmland. However, the microbial mechanism driving soil nutrient cycling in conservation tillage and its regulation pathway remain unclear. Based on a positioning experiment in black soil areas, this study systematically compared the effects of no-tillage (NT) and moldboard tillage (MT) combined with different straw returning amounts (straw non-returning, NS; straw half-returning, HS; straw full-returning, TS) on the composition of soil carbon (C), nitrogen (N) and phosphorus (P) and focused on the role of microbial community structure succession and functional changes in soil nutrient cycling. Microbial community remodeling driven by tillage measures was mainly regulated by C and N components. Bacterial modules 2 and 4 and fungal modules 1 and 2 were key for regulating the C, N and P cycle, of which 87 bacteria and 45 fungi taxa represented the core driving microorganisms. The total amount of no-tillage straw return reduced the formation and accumulation of labile organic carbon fractions by enriching yeast-like fungi and inhibiting the expression of complex organic matter decomposition genes. Tillage mainly promoted the accumulation of labile organic carbon fractions and nutrient release by regulating the bacterial community, while no-tillage straw returning promoted the accumulation of total organic carbon and organic nitrogen fixation by promoting the fungal community. This study revealed the biological pathway of conservation tillage that drives soil nutrient cycling by regulating key microbial communities. It also provides a microbiological basis for sustainable soil management in black soil areas.

In mitigating agricultural nitrous oxide (N₂O) emissions, partially substituting chemical nitrogen (N) fertilizers with organic amendments is widely advocated for; however, the effectiveness of this approach varies, and the optimal substitution ratio remains unclear. This study employed a long-term field experiment in a maize cropping system, integrating in situ N₂O flux monitoring, soil analysis, and metagenomic sequencing to investigate the effects of substituting synthetic N fertilizer with sheep manure at different ratios (one-sixth, one-third, and full substitution) on cumulative N₂O emissions and underlying microbial mechanisms. The results showed that substituting one-third of chemical N with sheep manure (OF2) most effectively reduced cumulative N₂O emissions, by 18.64% (2021) and 47.00% (2022), compared to conventional chemical fertilization (NPK). This treatment optimized key soil properties, significantly lowering soil nitrate (NO₃⁻-N) and ammonium (NH₄⁺-N) concentrations while increasing soil organic matter. Metagenomic analysis revealed that the mitigation was primarily driven by a coordinated shift in the nitrogen-cycling microbial functional gene network: OF2 significantly enhanced the abundance of N₂O reductase genes (nosZ clades I and II) and increased the nosZ/(nirK + nirS) gene ratio, thereby strengthening the genetic potential for complete denitrification (N₂O → N₂). Partial least squares path modeling confirmed that soil properties indirectly reduced N₂O emissions, primarily by regulating the microbial community and functional gene abundances. This study provides mechanistic evidence that partial organic substitution (with one-third sheep manure) mitigates N₂O emissions by optimizing the soil habitat and reprogramming the functional gene network of nitrogen-cycling microbes, with a key emphasis on enhancing the N₂O reduction pathway.

Long-term crop rotation can improve soil function and crop performance, but it remains unclear whether rotation history can simultaneously alleviate drought-induced oxidative injury in spring wheat leaves and roots. To address this gap, we used a long-term field rotation experiment established in 2016 in the western foothills of the Greater Khingan Mountains. Four cropping systems were selected: spring wheat–potato rotation (R1), spring wheat–potato–rape rotation (R2), spring wheat–rape rotation (R3), and continuous spring wheat cropping (C1). In 2022, wheat occurred naturally in all rotation sequences, and all plots were planted with the same spring wheat cultivar (‘Longmai 36’) to enable comparison among different rotation histories. Drought stress was imposed from late jointing, and at anthesis, ROS-related levels, malondialdehyde (MDA), glutathione (GSH), and proline (Pro), as well as the activities of superoxide dismutase (SOD) and peroxidase (POD), were determined in the flag leaves and roots of spring wheat under normal-water (NC) and drought-stress (HC) conditions. Under drought stress, rotation significantly increased yield (R1 and R2 by 73.3% and 77.7% vs. C1, respectively, partly reflecting the low C1 baseline associated with continuous cropping) and reduced drought-induced accumulation of ROS-related levels and MDA, along with excessive antioxidant and osmotic responses. R1 better protected leaves, while R2 optimized root osmotic regulation. Two-way ANOVA revealed significant drought × rotation interactions for most leaf traits (p < 0.01) but not for root ROS-related levels, SOD, or POD, indicating organ-specific regulation. R1 and R2 show strong drought resilience potential, warranting multi-year, multi-site validation.