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Soil sterilization integrated with agronomic measures is an effective method to reduce soilborne replant diseases. However, the effect of vermicompost or biochar application after soil sterilization on soilborne diseases is poorly understood. A pot experiment was conducted in American ginseng to investigate the effects of vermicompost (VF), biochar (BF), and a combination of vermicompost and biochar (VBF) applied after soil sterilization on the incidence of Fusarium root rot using natural recovery (F) as control. After one growing season, the disease index of root rot, the phenolic acids, and the microbial communities of American ginseng rhizosphere soil were analyzed. The disease index of VF, BF, and VBF decreased by 33.32%, 19.03%, and 80.96%, respectively, compared with F. The highest bacterial richness and diversity were observed in the rhizosphere soil of VBF. Besides, VF and VBF significantly increased the relative abundance of beneficial bacteria (Pseudomonas, Lysobacter, and Chryseolinea) in the rhizosphere soil. Higher concentrations of vanillin, one of the phenolic acids in the roots exudates, were recorded in the rhizosphere soils of BF and VBF. The vanillin concentration showed a significant negative correlation with the disease index. To conclude, vermicompost improved the beneficial bacteria of the rhizosphere soil, while biochar regulated the allelopathic effect of the phenolic acids. The study proposes a combined application of biochar and vermicompost to the rhizosphere soil to control Fusarium root rot of replanted American ginseng effectively.Key pointsVermicompost improves the relative abundance of rhizosphere beneficial bacteria.Biochar inhibits the degradation of phenolic acids by adsorption.The combination of vermicompost and biochar enhances the disease control effect.

Fusarium head blight (FHB) and Fusarium root rot (FRR) are important diseases of small-grain cereals caused by Fusarium species. While host response to FHB has been subject to extensive study, very little is known about response to FRR and the transcriptome responses of FHB and FRR have not been thoroughly compared. Brachypodium distachyon (Bd) is an effective model for investigating host responses to both FHB and FRR. In this study the transcriptome response of Bd to F. graminearum (Fg) infection of heads and roots was investigated. An RNA-seq analysis was performed on both Bd FHB and FRR during the early infection. Additionally, an RNA-seq analysis was performed on in vitro samples of Fg for comparison with Fg gene expression in planta . Differential gene expression and gene-list enrichment analyses were used to compare FHB and FRR transcriptome responses in both Bd and Fg. Differential expression of selected genes was confirmed using RT-qPCR. Most genes associated with receptor signalling, cell-wall modification, oxidative stress metabolism, and cytokinin and auxin biosynthesis and signalling genes were generally upregulated in FHB or were downregulated in FRR. In contrast, Bd genes involved in jasmonic acid and ethylene biosynthesis and signalling, and antimicrobial production were similarly differentially expressed in both tissues in response to infection. A transcriptome analysis of predicted Fg effectors with the same infected material revealed elevated expression of core tissue-independent genes including cell-wall degradation enzymes and the gene cluster for DON production but also several tissue-dependent genes including those for aurofusarin production and cutin degradation. This evidence suggests that Fg modulates its transcriptome to different tissues of the same host.

Sustainable use of nanotechnology in crop protection requires an understanding of the plant’s life cycle, potential toxicological impacts of nanomaterials and their mechanism of action against the target pathogens. Herein, we show some properties of a candidate antifungal nanocomposite made from copper oxide (CuO; otherwise an essential soil nutrient) nanoparticles (NPs), with definite size and shape, decorating the surface of reduced graphene oxide (rGO) nanosheets. The successful preparation of the rGO-CuO NPs was confirmed by spectroscopic and microscopic analyses, and its antifungal activity against wild strains of Fusarium oxysporum affecting tomato and pepper plants was successfully confirmed. A comparative analysis in vitro indicated that this nanocomposite had higher antifungal activity at only 1 mg/L than the conventional fungicide Kocide 2000 at 2.5 g/L. Further investigation suggested that rGO-CuO NPs creates pits and pores on the fungal cell membranes inducing cell death. In planta results indicated that only 1 mg/L from the nanocomposite is required to reduce Fusarium wilt and root rot diseases severity below 5% for tomato and pepper plants without any phytotoxicity for about 70 days. Comparatively, 2.5 g/L of Kocide 2000 are required to achieve about 30% disease reduction in both plants. The present study contributes to the concept of agro-nanotechnology, showing the properties of a novel ecofriendly and economic nanopesticide for sustainable plant protection.

The present study demonstrates plant growth promotion and induction of systemic resistance in pea ( Pisum sativum ) plant against Fusarium oxysporum f.sp. pisi by two bacterial endophytes, Pseudomonas aeruginosa OS_12 and Aneurinibacillus aneurinilyticus OS_25 isolated from leaves of Ocimum sanctum Linn. The endophytes were evaluated for their antagonistic potential against three phytopathogens Rhizoctonia solani , F. oxysporum f. sp. pisi , and Pythium aphanidermatum by dual culture assay. Maximum inhibition of F. oxysporum f. sp. pisi was observed by strains OS_12 and OS_25 among all root rot pathogens. Scanning electron microscopy of dual culture indicated hyphal distortion and destruction in the case of F. oxysporum f. sp. pisi . Further, volatile organic compounds (VOCs) were identified by gas chromatography–mass spectrometry (GC-MS). The GC-MS detected eight bioactive compounds from hexane extracts for instance, Dodecanoic acid, Tetra decanoic acid, L -ascorbic acid, Trans -13-Octadecanoic acid, Octadecanoic acid. Both the endophytes exhibited multifarious plant growth promoting traits such as indole acetic production (30–33 μg IAA ml –1 ), phosphate solubilization, and siderophore and ammonia production. Pot trials were conducted to assess the efficacy of endophytes in field conditions. A significant reduction in disease mortality rate and enhancement of growth parameters was observed in pea plants treated with consortium of endophytes OS_12 and OS_25 challenged with F. oxysporum f.sp. pisi infection. The endophytic strains elicited induced systemic resistance (ISR) in pathogen challenged pea plants by enhancing activities of Phenylalanine ammonia lyase (PAL), peroxidase (PO), polyphenol oxidase (PPO), ascorbate oxidase (AO), catalase (CAT) and total phenolic content. The endophytes reduced the oxidative stress as revealed by decrease in malondialdehyde (MDA) content and subsequently, lipid peroxidation in host plant leaves. Robust root colonization of pea seedlings by endophytes was observed by scanning electron microscopy (SEM) and fluorescence microscopy. Thus, plant growth promoting endophytic P. aeruginosa and A. aneurinilyticus can be further exploited through bio-formulations for sustainable protection of crops against root rot diseases as bio-control agents.

Tobacco (Nicotiana tabacum L.) production is centred in the northwestern region of Argentina (NWA), where the incidence of root rot and stem diseases has increased considerably in recent years. This study aimed to analyse the genetic, morphological and pathogenic diversity of the Fusarium oxysporum and F. solani complexes (hereafter FOSC-FSSC), causing Fusarium wilt and root rot. One hundred tobacco fields were surveyed at six locations during two consecutive seasons, and 130 isolates were recovered from symptomatic tobacco plants. The isolates were characterized by morphological traits, molecular characteristics (EF1-α sequence) and pathogenicity tests. All of the isolates were identified as members of the FOSC or FSSC, exhibiting considerable intra-group variation. Three morphotypes were differentiated based on morphological characters in both complexes. The phylogenetic tree generated from the EF1-α sequences confirmed the isolates’ identification. The pathogenicity of the isolates towards tobacco seedlings was assessed in a greenhouse. Considerable variability in pathogenicity was observed among the isolates. Differences in the levels of pathogenicity were recorded. In the FOSC and FSSC, 81% and 60% of the isolates were pathogenic, respectively. In this study, members of FOSC and FSSC exhibited considerable variability in morphological characteristics and virulence, and a portion of them were non-pathogenic for tobacco. To the best of our knowledge, this study is the first to provide information on the variability of the pathogens associated with tobacco wilt and root rot in NWA. This work contributes to the development of sustainable management strategies in tobacco production.

Alfalfa ( Medicago sativa ) is the most widely cultivated and important forage crop worldwide, owing to its high protein content. However, alfalfa Fusarium root rot seriously affects and restricts the yield and quality. This study explores the response mechanism of alfalfa to Fusarium root rot. we used transcriptomic and proteomic methods to analyze differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) in alfalfa inoculated with Fusarium acuminatum on 0, 3, and 13 days. In total, 13,017 DEGs (6902 upregulated, 6115 downregulated) and 4830 DEPs (697 upregulated, 659 downregulated) were identified. Gene Ontology (GO) and Kyoto and Encyclopedia of Genes and Genomes (KEGG) analyses indicated that the DEGs and DEPs were mainly enriched in the cell cortex, flavonoid biosynthesis, and amino acid metabolism on day 3, whereas on day 13, they were primarily enriched in the cell wall, defense response, and flavonoid biosynthesis. Transcriptome and proteome analyses showed the same expression pattern of 81 genes and their corresponding proteins, which were mainly enriched in amino acid metabolism, cell wall synthesis, flavonoid biosynthesis, glucose metabolism, and plant-pathogen interactions. The results indicate that when alfalfa responds to infection by F. acuminatum , cell walls, antioxidant and defense-related enzymes, as well as genes involved in glucose metabolism and disease resistance, play important roles.This study contributes to the understanding of the molecular mechanism of the alfalfa response to F. acuminatum infection and provides an important basis for further research and in-depth characterization of candidate genes for breeding alfalfa root rot resistance.

The dynamic of soil-borne disease is closely related to the rhizosphere microbial communities. Maize–soybean relay strip intercropping has been shown to significantly control the type of soybean root rot that tends to occur in monoculture. However, it is still unknown whether the rhizosphere microbial community participates in the regulation of intercropped soybean root rot. In this study, rhizosphere Fusarium and Trichoderma communities were compared in either healthy or root-rotted rhizosphere soil from monocultured and intercropped soybean, and our results showed the abundance of rhizosphere Fusarium in intercropping was remarkably different from monoculture. Of four species identified, F. oxysporum was the most aggressive and more frequently isolated in diseased soil of monoculture. In contrast, Trichoderma was largely accumulated in healthy rhizosphere soil of intercropping rather than monoculture. T. harzianum dramatically increased in the rhizosphere of intercropping, while T. virens and T. afroharzianum also exhibited distinct isolation frequency. For the antagonism test in vitro, Trichoderma strains had antagonistic effects on F. oxysporum with the percentage of mycelial inhibition ranging from 50.59–92.94%, and they displayed good mycoparasitic abilities against F. oxysporum through coiling around and entering into the hyphae, expanding along the cell–cell lumen and even dissolving cell walls of the target fungus. These results indicate maize–soybean relay strip intercropping significantly increases the density and composition proportion of beneficial Trichoderma to antagonize the pathogenic Fusarium species in rhizosphere, thus potentially contributing to the suppression of soybean root rot under the intercropping.

Alfalfa Fusarium Root Rot (AFRR) is a serious soil-borne disease with a complex pathogenicity. Diseased samples suspected of AFRR were collected from Hohhot, Ordos, Hulunbeier, Chifeng, and Bayannur in Inner Mongolia, China, leading to 317 isolates. The isolates were identified as Fusarium acuminatum, F. solani, F. equiseti, F. incarnatum, F. oxysporum, F. avenaceum, F. verticillioides, F. proliferatum, F. falciforme, F. tricinctum, F. virguliforme, and F. redolens, and the results of pathogenicity testing showed that 12 Fusarium species could cause alfalfa root rot. Among these, F. verticillioides, F. falciforme, and F. virguliforme have not previously been reported to cause AFRR in China. Although the population structure of the pathogens differed in different regions, the dominant pathogenic species was F. acuminatum. Fungicide toxicity tests showed that seven fungicides inhibited F. acuminatum, of which fludioxonil, kresoxim-methyl, and triadimefon were found to be strongly toxic towards F. acuminatum with EC50 values of 0.09, 2.28, and 16.37 μg/mL, respectively, suggesting that these could be used as alternative fungicides for the control of AFRR. The results of this study can provide a theoretical basis for exploring the occurrence and epidemiology of alfalfa root rot and strategies for its control.

Fusarium root rot, caused by Fusarium solani , is a major post-harvest disease in sweet potatoes ( Ipomoea batatas (L.) Lam.). An effective strategy for controlling this disease is the development of resistant varieties. In this study, a genome-wide association study (GWAS) was conducted on 96 sweet potato genotypes to identify novel candidate loci and dissect the genetic basis of Fusarium root rot resistance. Genotyping was performed using genotyping-by-sequencing (GBS), and 44,255 SNPs were identified after filtering. The genotypes (n = 96) were evaluated through resistance tests in 2021 and 2022, separately and combined. The GWAS identified two significant SNP markers (LG3_22903756 and LG4_2449919) on chromosomes 3 and 4 associated with Fusarium root rot resistance, respectively. Lesion length showed significant differences between homozygous A and G alleles of LG3_22903756, which can potentially be used to develop molecular markers for selecting accessions resistant to Fusarium root rot. Expression analysis of 11 putative genes flanking the significant SNPs revealed the alteration in the expression of nine genes, indicating their possible involvement in Fusarium root rot resistance. The results of this study will aid in the marker-assisted selection and functional analysis of candidate genes for Fusarium root rot resistance in sweet potatoes.