Plasmopara viticola, the causal agent of grapevine downy mildew, exhibits substantial intraspecific variation in pathogenicity and genetic diversity, yet the genomic features underlying this variation remain incompletely characterized. Here, we sequenced and assembled two P. viticola isolates, PvH (from Vitis vinifera) and PvS (from V. amurensis), using PacBio HiFi sequencing, and performed comparative genomic analysis. Two complete genome assemblies (17 chromosomes) of P. viticola (PvH: 115.3 Mb; PvS: 113.0 Mb) were generated and revealed that nearly 90% of the putative effectors exist as local duplicated gene clusters. Comparative genomics uncovered distinct intraspecific expansion, deletion, and diversification of putative effectors driven by local segmental, tandem, and proximal duplication events in P. viticola. Specifically, PvH exhibited a ~1.4-fold increase in CRNs (PvH: 237; PvS: 183; PV221: 169) and harbored 35 strain-specific CRNs. These differential effectors were predominantly clustered in complex structural variation hotspots (SVs, duplication and inversion). Notably, 104 putative effectors-including 21 RxLRs, 59 CRNs, and 24 CAZymes-were located within inversion regions. Together, our results highlight a highly dynamic genome architecture in P. viticola, in which SV and local gene duplication are closely associated with effector diversification. This study provides a genome-resolved comparative framework for understanding intraspecific genomic diversity in P. viticola and establishes a foundation for future population-level and functional investigations.

Downy mildew, caused by Plasmopara viticola, is a devastating disease that threatens global grape production, with chemical control remaining the most effective management strategy. However, the repeated application of fungicides has led to widespread resistance in P. viticola populations, while data on the resistance of P. viticola to metalaxyl (MET), cymoxanil (CYM), and cyazofamid (CYA) in China remain limited. In this study, the resistance status of P. viticola to these three fungicides was evaluated across 9 major grape-growing regions in China using leaf-disc bioassays, and potential cross- and multi-resistance patterns were assessed. The majority of isolates (127/233) exhibited either lower resistance (33.48%) or moderate resistance (21.03%) to MET based on the minimum inhibitory concentration (MIC) of 10 μg/mL and 100 μg/mL. Baseline sensitivity profiles for CYM and CYA were established as 8.69 ± 0.64 μg/mL and 0.42 ± 0.05 μg/mL, respectively, using 170 and 137 isolates. The total resistance frequency of P. viticola to CYM was 29.42% (21.18% low resistance, 8.24% moderate resistance), while that to CYA was 28.47% (18.25% low resistance, 9.49% moderate resistance, 0.73% high resistance). A weak but significant positive correlation was detected between CYM and CYA sensitivities (r = 0.193, p = 0.0196), and 13 isolates exhibited resistance to both fungicides, indicating potential multi-resistance risk. Significant regional differences in resistance profiles were observed among populations (p < 0.05), and no overall fitness penalties were detected. These findings highlight the necessity of region-specific and integrated resistance management strategies for sustainable control of grape downy mildew in China.

Rhizosphere microbes regulated by root exudates play important roles in promoting plant growth and suppressing soil-borne diseases. However, their functions in monoculture systems are not well studied. Here, we integrated metabolomic and microbiome analyses to compare root exudate profiles and rhizosphere communities of Fusarium oxysporum f. sp. cucumerinum (Foc) resistant (CL11) and susceptible (ZN6) cultivars grown in naturally infested, continuous-cropping soil. The asymptomatic, resistant cultivar CL11 (CL11H) exhibited a metabolic signature enriched in defensive compounds (ganoderic acid I and L-isoleucine) and harbored a beneficial bacterial community dominated by Streptomyces, Cellvibrio, and Ensifer. While the asymptomatic susceptible cultivar ZN6 (ZN6H) showed elevated levels of primary metabolites (methylmalonic and succinic acids) and an enrichment in the relative abundance of Amycolatopsis and Flavobacterium. Upon symptom development, susceptible symptomatic ZN6 (ZN6D) mounted a "cry-for-help" response, accumulating L-tryptophan and citric acid, which correlated with recruitment of Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium. Conversely, resistant symptomatic CL11 (CL11D) deployed a metabolic profile (L-3-cyanoalanine, 4-hydroxybenzoyl glucose, D-fructose), which enriched Bacillus and Cellvibrio. Exogenous application of citric acid, L-isoleucine, L-tryptophan, hexadecanedioic acid, and succinic acid to susceptible ZN6 plants significantly suppressed wilt disease. These metabolites restructured the rhizosphere bacterial communities, demonstrated by enrichments of Pseudomonas, Burkholderia-Caballeronia-Paraburkholderia, and Comamonadaceae by L-tryptophan, as well as Pseudomonas and Bacillus promoted by L-isoleucine and citric acid, respectively. Moreover, succinic acid suppressed disease through microbiome-mediated mechanisms despite its in vitro positive effect on Foc growth. These findings demonstrate that root exudates are linked to cultivar-specific disease outcomes, and that target metabolite application can suppress Fusarium wilt through microbiome-mediated mechanisms or a combined antifungal mode.

Clonostachys chloroleuca is a potential biocontrol fungus capable of parasitizing various plant fungal pathogens. In the highly efficient strain 67-1, we identified a glutamate dehydrogenase gene, CrGdh2, during mycoparasitization of Sclerotinia sclerotiorum. CrGdh2 is essential for the biocontrol activity of C. chloroleuca, as its deletion compromised control efficacy against Sclerotinia rot and tomato root rot by 27.9% and 39.8%, respectively, compared to the wild-type strain. Acetylated CrGdh2 was investigated using acetylation and deacetylation mimetic mutants. The results showed that when strains were inoculated on S. sclerotiorum sclerotia, no obvious infection structures were detected in ΔCrGdh2 and ΔCrGdh2-CK404R. In pot experiments, both mutants also showed over 30% reduction in biocontrol efficacy, in contrast to the wild-type and ΔCrGdh2-CK404Q strains, indicating the essential role of K404 acetylation. The findings reveal the roles of glutamate dehydrogenase and its acetylation in mycoparasitism, providing novel insight into the biocontrol mechanisms of C. chloroleuca.

Fusarium oxysporum f. sp. cucumerinum (Foc) infected cucumber (Cucumis sativus), leading to serious wilt disease and great economical losses worldwide. During infection, Foc secreted various protein effectors to facilitate colonization and disease development. Here, we identified a novel virulence effector, designated FoCup, which was highly up-regulated during Foc-cucumber interactions according to transcriptomic data. Bioinformatic analysis using SignalP-5.0 and InterPro predicted an N-terminal signal peptide and a cupredoxin domain in FoCup. Phylogenetic analysis indicated that FoCup is highly conserved within the Fusarium genus. Its secretory capability was experimentally confirmed by the yeast invertase secretion assay. Subcellular localization in Nicotiana benthamiana leaf cells revealed that FoCup-GFP predominantly localized to the plasma membrane, co-localizing with the membrane marker CD3-1007 (AtPIP2A-mCherry). Functional characterization demonstrated that ΔFoCup knockout mutants exhibited significantly reduced virulence on cucumber, accompanied by decreased conidiation, and increased sensitivity to osmotic stressors (e.g., glycerol, sorbitol, NaCl, and KCl). In contrast, mycelial growth remained comparable to the wild-type (WT) strain. The impaired virulence and conidiation in the knockout mutants (ΔFoCup) were fully restored in the complementary mutants (ΔFoCup+FoCup). Specifically, pathogenicity tests showed that the disease index caused by ΔFoCup was significantly reduced by 54.5and 62.5 compared to the wild type Foc, underscoring the critical role of FoCup in pathogenesis. Our findings provide new insights into the molecular mechanisms underlying Foc virulence.

Engineering root microbiomes holds great promise to enhance plant health. Enhanced plant resistance via breeding or genetic modification can promote recruiting beneficial microbes, but is challenging to achieve. Here we showed that calcium (Ca) addition caused significant changes in tomato physiology, resulting in enhanced immunity towards the pathogen Ralstonia solanacearum along with increased levels of salicylic acid (SA), sugar content, and defense enzyme activities in roots. High Ca levels significantly altered the root microbiomes, enriching sixteen bacterial genera, including Dyella japonica, Rhodanobacter glycinis, Paenibacillus polymyxa, and Pseudomonas aeruginosa, with the mostly enriched genus showing a 16.5-fold increase in the relative abundance compared to no Ca addition. Associated with the enhancement of these bacterial genera, tomato wilt incidence was reduced from 80 to 0

Root rot, a globally devastating disease of common bean (Phaseolus vulgaris L.), remains a major constraint on bean production across China. Despite its agricultural impact, the pathogen complex associated with this disease has been poorly characterized in most provinces. To address this critical knowledge gap, we conducted nationwide surveys during 2016–2018, systematically sampling 1–10 symptomatic plants from each of 121 (2016) and 170 (2018) field sites across 17 provinces in China’s major vegetable production regions. Isolates obtained from symptomatic root tissues underwent morphological screening, followed by molecular identification using partial sequences of EF1-α for Fusarium species and ITS regions for other genera. Pathogenicity of representative isolates was subsequently confirmed through controlled greenhouse assays. This integrated approach revealed fourteen fungal and oomycete genera, with Fusarium (predominantly F. oxysporum and F. solani) and Rhizoctonia (R. solani) emerging as the most prevalent pathogens. Notably, pathogen composition exhibited significant regional variation and underwent temporal shifts across developmental stages. Additionally, F. oxysporum, F. solani, and R. solani demonstrated significant interspecies associations with frequent co-occurrence in bean root rot systems. Collectively, this first comprehensive characterization of China’s common bean root rot complex not only clarifies spatial–temporal pathogen dynamics but also provides actionable insights for developing region- and growth stage-specific management strategies, particularly through targeted control of dominant pathogens during key infection windows.

Common bean root rot becomes serious in continuous cropping fields with over-application of chemical fertilizer. Through the standard field fertilization, the disease might be alleviated. This study aimed to investigate the impacts of standard field fertilization practices on bean root rot severity and rhizosphere microbial community shifts under continuous cropping. From 2018 to 2021, beans were monocultured for eight cycles in field soil in the greenhouse at an average interval of 4 months. Root rot severity was assessed at each cycle, and rhizosphere microbial communities were analyzed at 1st, 5th, and 7th cycles using high-throughput sequencing approach. Bean root rot severity was found to keep increasing until the 5th cycle and decreased sharply at the 7th cycle. Corresponding to the disease aggravation and suppression, Fusarium exhibited the highest abundance at the 1st cycle, followed by Plectosphaerella at the 5th cycle, and Dactylonectria at the 7th cycle. Pseudomonas showed the highest abundance in the rhizosphere soils at the 1st and 7th cropping cycles. Correlation analysis indicated that the soil microbes were closely related to disease severity as well as soil nitrogen and phosphorus contents. These findings suggest that continuous cropping of bean with standard field fertilization practices could create suppressive soil with reduced disease severity. This study revealed the microecological immune mechanism of continuous cropping of bean against root rot and provided cost-effective and highly efficient techniques for sustainable farming.

This review explores how soil texture and nutrient availability influence root exudate composition and their effects on rhizosphere microbial dynamics and disease suppression, ultimately affecting plant health and resilience. The findings reveal that clay soil has a dense structure and limited aeration. As a stress response, clay soil restricts root growth, prompts plants to release more exudates to enhance nutrient uptake and attracts beneficial microbes. In contrast, sandy soil, due to its loose texture, is easier for roots to penetrate, often resulting in less exudation. Nutrient availability plays a pivotal role in shaping exudate profiles, such as coumarins and organic acids, which recruit beneficial microbes like Pseudomonas and Trichoderma harzianum, aiding in nutrient acquisition and disease suppression. The interaction between soil texture and nutrient levels creates a dynamic environment that shapes microbial community structure and promotes disease suppression. This review highlights the current understanding of how variations in soil texture and nutrient levels impact root exudates and microbial communities in the rhizosphere. It also identifies key gaps, particularly the need for long-term field studies to explore these interactions under diverse environmental conditions. These insights are critical for developing targeted rhizosphere management strategies, paving the way for more resilient and productive agricultural systems.

Microbial inoculants are critical tools for improving soil health and crop growth within sustainable agriculture frameworks. Despite numerous microorganisms being identified as potential candidates, their transition from laboratory efficacy to field application remains constrained by the complex and variable conditions of field environments. This review critically examines the current state of microbial inoculant research, pinpointing key challenges such as the lack of diversity in test environments and the insufficient integration of agronomic practices crucial for practical adoption. We propose the farmer Participatory research (FPR) model as a robust methodology to address these challenges, emphasizing the co-creation of knowledge between researchers and farmers. This approach uses the practical insights of farmers and integrates multidisciplinary scientific advances to ensure that the development of microbial inoculants is scientifically sound and practically viable in diverse agricultural settings. By adopting FPR principles, this review offers a detailed roadmap for future research, emphasizing the importance of farmer-centric approach in integrating advanced technologies like amplicon sequencing, machine learning, synthetic biology, and systems carriers in optimizing microbial inoculant performance. This paradigm shift towards a collaborative, multidisciplinary approach is poised to significantly improve the efficacy of field trials and establish robust agronomic management strategies for microbial inoculants application, ultimately advancing microbial inoculant research.

ABSTRACT Serine proteases are a group of important hydrolytic enzymes that play vital roles in various cellular processes in fungi. In this study, the S8 serine protease-encoding gene CrKP43 was identified in the highly efficient Clonostachys chloroleuca 67–1 (formerly C. rosea 67–1) strain, which was markedly upregulated when parasitizing Sclerotinia sclerotiorum . The function of CrKP43 was investigated using gene deletion and complementation, and the results indicated that the lack of CrKP43 resulted in deformed fungal hyphae and cell morphology, inhibition of conidiation, and decreased antagonistic activity toward the pathogenic fungus Fusarium oxysporum f. sp. cucumerinum . Moreover, the mutants displayed much weaker mycoparasitic ability to S. sclerotiorum sclerotia and lower control efficiency against soybean Sclerotinia rot compared with the wild-type strain. All biological characteristics and biocontrol activities were recovered when the CrKP43 gene was reinserted into the fungus. Using qRT-PCR analysis and protein-protein interaction assays, it was further proved that the CrKP43 protein interacted with the mitogen-activated protein kinase (MAPK) Crmapk, suggesting serine proteases might be involved in the mycoparasitism of C. chloroleuca with the regulation of Crmapk. The findings improve our knowledge of serine proteases and their regulation in mycoparasites and help to illuminate the mechanisms underlying mycoparasitism of C. chloroleuca . IMPORTANCE Mycoparasites play important roles in the biocontrol of plant fungal diseases, during which they secret multiple hydrolases such as serine proteases to degrade their fungal hosts. In this study, we demonstrated that the serine protease CrKP43 was involved in C. chloroleuca development and mycoparasitism with the regulation of Crmapk. To the best of our knowledge, it is the first report on the functions and regulatory mechanisms of serine proteases in C. chloroleuca . Our findings will provide new insight into the regulatory mechanisms of serine proteases in mycoparasites and contribute to clarifying the mechanisms underlying mycoparasitism of C. chloroleuca , which will facilitate the development of highly efficient fungal biocontrol agents as well.

Fusarium oxysporum f. sp. cucumerinum (Foc) is a prominent pathogen that adversely affects cucumber (Cucumis sativus) production. In the pathogen's parasitic lifestyle, the pathogenesis and virulence evolution may be regulated by lysine acetylation, as demonstrated in many living organisms. However, its specific function in Foc remains poorly understood. In this study, the acetylome profiles of a mild virulence strain (foc-3b) and its derived virulence-enhanced strain (Ra-4) were analyzed before and post-inoculation on cucumber plants. In total, 10,664 acetylation sites were identified corresponding to 3874 proteins, and 45 conserved acetylation motifs were detected. Through comparison of the acetylomes, numerous differentially lysine-acetylated proteins were enriched in energy metabolism and protein processing processes, indicating the critical role of lysine acetylation during the transition from the saprotrophic lifestyle to the parasitic lifestyle. Comparative acetylome analyses on the two virulence-differentiated strains revealed that several differentially lysine-acetylated proteins were involved in pathways of defense response and energy metabolism. Ra-4 showed enhanced energy metabolism compared to foc-3b. This indicates that robust metabolic activity is required to achieve high virulence and facilitating adaptive evolution. Additionally, faster host responses are supported by an ample energy supply enhancing virulence. Thus, lysine acetylation plays a crucial role in the pathogenesis and virulence evolution of Foc.

Background Meloidogyne incognita greatly restricts the production of protected vegetables in China. Application of biocontrol agent Purpureocillium lilacinum is an important practice to control the nematode; however, instability usually occurs especially in heavily infested field. This study aimed to illustrate the high efficiency of P. lilacinum agent with fumigant Dazomet in vitro. Results P. lilacinum YES-2-14 showed strong parasitic and nematicidal activities to M. incognita. Pre-treatment with Dazomet significantly enhanced the biocontrol effects of the fungus. After fumigation with Dazomet at a dosage of 7.5 mg kg(-1) soil, parasitism of YES-2-14 on M. incognita eggs increased by more than 50%. Meanwhile, when P. lilacinum fermentation filtrate treated following Dazomet fumigation at 10 and 20 mg kg(-1) soil, the mortalities of second-stage juveniles (J(2)s) increased by 110.2% and 72.7%, respectively. Both Dazomet and P. lilacinum significantly reduced the penetration ability of J(2)s to tomato roots. When P. lilacinum filtrate used alone, the J(2)s penetrating into the young roots decreased by 48.8% at 4 dpi; while in the combined treatment, almost no J(2) was detected within the roots at 4 dpi and the number of knots reduced by more than 99% at 45 dpi, indicating a synergistic effect of the biocontrol fungus and fumigant. Conclusions Pre-treatment with Dazomet greatly increased the biocontrol efficacy of P. lilacinum to M. incognita. This research provides insight into the efficient management of plant parasitic nematodes and effective use of biocontrol agents.

The purpose of this study is to obtain the biocontrol bacteria to control the soft rot disease of Chinese cabbage.An antagonistic strain 26B was screened from 38 actinomycete strains isolated from the rhizosphere of Chinese cabbage by Oxford cup method.Strain 26B was identified as Streptomyces based on its morphological characteristics and its 16S rRNA gene sequence analyses.The cell free fermentation filtrate of strain 26B showed high antibacterial activity against Pectobacterium carotovorum subsp.brasiliensis BC1 and three casual bacteria of potato blackleg disease,and the antibacterial diameter against BC1 reached 23.97 mm.The germination assay by seed-soaking showed that the cell free fermentation filtrate of strain 26B significantly promoted the germination potential,germination index,root length and fresh weight of Chinese cabbage seeds.Effects of cell free fermentation filtrate of strain 26B on the inhibition of BC1-gfp colonized on the Chinese cabbage roots was examined by root-dipping method.The results showed that the number of BCl-gfp on cabbage roots reached 2.3×109 CFU/g after 48 hours’ incubation in the treatment with BCl-gfp suspension,while no BCl-gfp was detected on the cabbage roots treated with the premixed mixture of BCl-gfp suspension and sterilized fermentation filtrate of strain 26B at a volume ratio of 10%.The bioassay test in potting soil showed that the efficacy of cell free fermentation filtrate of strain 26B on the control of soft rot disease reached 96.0% and 89.8%,respectively,in soil with water content of 14% and 20%.The above results indicated that Streptomyces 26B has great potential to be applied as a biocontrol strain,and its biocontrol efficacy can be improved through coordinately management of soil water content.

Cucumber plants commonly suffer from Fusarium wilt disease, which is caused by Fusarium oxysporum f. sp. cucumerinum (Foc). Although resistant cultivars assist with Fusarium wilt disease control, enhancement of the virulence of Foc has been identified after monoculture of wilt-resistant cultivars. To investigate the biological characteristics that contribute to the virulence evolution of Foc, a wildtype strain foc-3b (WT) and its virulence-enhanced variant Ra-4 (InVir) were compared in terms of their growth, reproduction, stress tolerance, and colonization in cucumber plants. The InVir strain showed similar culture characteristics on PDA media to the WT strain but produced significantly more conidia (>two fold), with a distinctly higher germination rate (>four fold) than the WT strain. The colony diameter of the InVir strain increased faster than the WT strain on PDA plates; however, the mycelia dry weight of the InVir was significantly lower (<70%) than that of the WT harvested from PDB. The InVir strain exhibited a significant increase in tolerance to osmolality (1 M NaCl, 1 M KCl, etc.). The GFP-labeled InVir strain propagated in the cucumber vascular faster than the WT strain. These results suggest that increased conidia production and germination in vitro may correlate with virulence enhancement in Fusarium oxysporum f. sp. cucumerinum. This study will provide an insight into its virulence evolution and help us understand the mechanisms underlying the evolutionary biology of F. oxysporum.

The root microbiota contributes to the plant's defense against stresses and pathogens. However, the co-association pattern of functional bacteria that improves plant resistance has not been interpreted clearly. Using Illumina high-throughput sequencing technology, the root bacterial community profiles of six cucumber cultivars with different resistance in response to the causative agent of cucumber Fusarium wilt (CFW), Fusarium oxysporum f. sp. cucumerinum (Foc), were analyzed. The principal coordinate analysis indicated that the interactions of the cultivars and pathogens drove the cucumber root bacterial communities (p = 0.001). The resistance-specific differential genera across the cultivars were identified, including Massilia in the resistant cultivars, unclassified Enterobacteriaceae in resistant CL11 and JY409, Pseudomonas in JY409, Cronobacter in moderately resistant ZN106, and unclassified Rhizobiaceae and Streptomyces in susceptible ZN6. The predominant root bacterium Massilia accounted for the relative abundance of up to 28.08-61.55%, but dramatically declined to 9.36% in Foc-inoculated susceptible ZN6. Pseudomonas ASV103 and ASV48 of Pseudomonadaceae and Cronobacter ASV162 of Enterobacteriaceae were consistently differential across the cultivars at the phylum, genus, and ASV levels. Using the culture-based method, antagonistic strains of Enterobacteriaceae with a high proportion of 51% were isolated. Furthermore, the bacterial complexes of Pantoea dispersa E318 + Pseudomonas koreensis Ps213 and Cronobacter spp. C1 + C7 reduced the disease index of CFW by 77.2% and 60.0% in the pot experiment, respectively. This study reveals the co-association of specific root bacteria with host plants and reveals insight into the suppressing mechanism of resistant cultivars against CFW disease by regulating the root microbiota.

Clonostachys rosea is an important mycoparasitism biocontrol agent that exhibits excellent control efficacy against numerous fungal plant pathogens. Transcriptomic sequencing may be used to preliminarily screen mycoparasitism-related genes of C. rosea against fungal pathogens. The present study sequenced and analyzed the transcriptome of C. rosea mycoparasitizing a Basidiomycota (phylum) fungal pathogen, Rhizoctonia solani, under three touch stages: the pre-touch stage, touch stage and after-touch stage. The results showed that a number of genes were differentially expressed during C. rosea mycoparasitization of R. solani. At the pre-touch stage, 154 and 315 genes were up- and down-regulated, respectively. At the touch stage, the numbers of up- and down-regulated differentially expressed genes (DEGs) were 163 and 188, respectively. The after-touch stage obtained the highest number of DEGs, with 412 and 326 DEGs being up- and down-regulated, respectively. Among these DEGs, ABC transporter-, glucanase- and chitinase-encoding genes were selected as potential mycoparasitic genes according to a phylogenetic analysis. A comparative transcriptomic analysis between C. rosea mycoparasitizing R. solani and Sclerotinia sclerotiorum showed that several DEGs, including the tartrate transporter, SDR family oxidoreductase, metallophosphoesterase, gluconate 5-dehydrogenase and pyruvate carboxylase, were uniquely expressed in C. rosea mycoparasitizing R. solani. These results significantly expand our knowledge of mycoparasitism-related genes in C. rosea and elucidate the mycoparasitism mechanism of C. rosea.

Long-term overfertilization increases soil salinity and disease occurrence and reduces crop yield. Integrated application of microbial agents with low fertigation input might be a sustainable and cost-effective strategy. Herein, the promoting effects of Bacillus velezensis B006 on the growth of Chinese cabbage under different fertigation conditions in field trials were studied and the underlying mechanisms were revealed. In comparison with normal fertigation (water potential of −30 kPa and soluble N, P, K of 29.75, 8.26, 21.48 Kg hm−2) without B006 application, the combination of B. velezensis B006 and reduced fertigation input (−50 kPa and N, P, K of 11.75, 3.26, 6.48 Kg hm−2) promoted cabbage growth and root development, restrained the occurrence of soft rot disease, and improved the yield. High-performance liquid chromatography (HPLC) analyses indicated that B006 application promoted the production of indole-3-acetic acid and salicylic acid in cabbage roots, which are closely related to plant growth. Rhizosphere microbiota analyses indicated that the combination of low fertigation input and B006 application promoted the enrichment of Streptomyces, Lechevalieria, Promicromonospora, and Aeromicrobium and the abundance of Lechevalieria was positively correlated with the root length and vitality. This suggested that the integrated application of reduced fertigation and Bacillus is highly efficient to improve soil ecology and productivity and will benefit the sustainable development of crop cultivation in a cost-effective way.

[目的]评估不同微生物菌处理对番茄土壤微生物多样性的影响,为改善土壤微生物多样性、增加番茄产量提供理论依据与参考.[方法]以水果型番茄农博粉18109 为试材,采用高通量测序技术,研究放线菌(T1)、枯草芽孢杆菌(T2)、哈茨木霉菌(T3)3 种微生物菌处理,以不施用微生物菌对照(CK)进行番茄土壤微生物多样性及与环境相关性的影响.[结果]哈茨木霉(T3)处理的土壤中细菌含量最高,放线菌(T1)处理的土壤中真菌含量最高,T1、T3 的细菌和真菌的比例均大于对照,土壤微生物呈现"细菌化".Alpha多样性显示T1 和T3 的细菌种类多于CK,T1、T2、T3 的真菌种类均少于CK;T2 处理的细菌Shannon和Simpson指数均低于CK,T1 和T3 处理的细菌Shannon和Simpson指数均高于CK,3 种微生物菌处理的真菌Shannon和Simpson指数均高于CK.对照、放线菌、枯草芽孢杆菌、哈茨木霉4 个处理间存在差异,相同处理间存在较强的一致性.T1 和T3 微生物菌处理的细菌和真菌多样性较为相似.细菌中Unspecified_iii1_15、Unspecified_RB41、Unspeci-fied_Gemm_5、Unspecified_Syntrophobacteraceae、Kaistobacter为优势细菌属.真菌中 Fusarium(镰刀菌属)、Un-specified_Chaetomiaceae(未分类毛壳菌科)、Unspecified_Pezizales、Unspecified_Hypocreales_fam_Incertae_sedis、Mor-tierella(被孢霉属)为优势真菌属,镰刀菌属(Fusarium)在4 个不同处理中相对丰度最高.细菌和真菌中叶宽与微生物群落分布间的相关性均最小,叶长、株高、茎粗和产量与微生物群落分布间的相关性高;放线菌和哈茨木霉对番茄土壤微生物的影响相对较大,叶长、叶宽、茎粗与放线菌的相关性最高,产量与哈茨木霉的相关性最高.[结论]不同微生物菌处理对番茄土壤微生物多样性影响不同,但放线菌和哈茨木霉对番茄土壤微生物的影响相对较大,叶长、叶宽、茎粗与放线菌的相关性最高,哈茨木霉与产量的相关性最高.

Clonostachys chloroleuca (formerly classified as C. rosea) is an important mycoparasite active against various plant fungal pathogens. Mitogen-activated protein kinase (MAPK) signaling pathways are vital in mycoparasitic interactions; they participate in responses to diverse stresses and mediate fungal development. In previous studies, the MAPK-encoding gene Crmapk has been proven to be involved in mycoparasitism and the biocontrol processes of C. chloroleuca, but its regulatory mechanisms remain unclear. Aldose 1-epimerases are key enzymes in filamentous fungi that generate energy for fungal growth and development. By protein-protein interaction assays, the glucose-6-phosphate 1-epimerase CrGlu6 was found to interact with Crmapk, and expression of the CrGlu6 gene was significantly upregulated when C. chloroleuca colonized Sclerotinia sclerotiorum sclerotia. Gene deletion and complementation analyses showed that CrGlu6 deficiency caused abnormal morphology of hyphae and cells, and greatly reduced conidiation. Moreover, deletion mutants presented much lower antifungal activities and mycoparasitic ability, and control efficiency against sclerotinia stem rot was markedly decreased. When the CrGlu6 gene was reinserted, all biological characteristics and biocontrol activities were recovered. These findings provide new insight into the mechanisms of glucose-6-phosphate 1-epimerase in mycoparasitism and help to further reveal the regulation of MAPK and its interacting proteins in the biocontrol of C. chloroleuca.