Climate change poses significant challenges for agricultural production, potentially altering crop distribution, productivity, and the prevalence of plant diseases. This study focuses on the fungus Verticillium dahliae which causes disease in over 400 plant species, significantly impacting cotton in most major cotton producing countries. We investigate how climate suitability for V. dahliae could change in the future, using New South Wales (NSW), Australia, as a case study. Our research examines the interplay between factors affecting the prevalence of V. dahliae infection, including fungal strain, temperature and rainfall. Using a 1992multi-criteria analysis approach, we evaluated climate suitability for V. dahliae under both historical and projected mid-21st century future climate conditions. This method combines peer-reviewed evidence with expert knowledge to assess potential impacts. Our findings suggest that climate change is likely to alter the number of months that are suitable for V. dahliae growth and potentially shift the distribution of fungal strains across NSW. Our modelling shows that the more aggressive defoliating strain is likely to become more prevalent in northern NSW, and the less aggressive non-defoliating strain is likely to become less prevalent, particularly in northern NSW. Our study provides valuable insights for agricultural planning and adaptation strategies in the face of climate change.

Verticillium wilt of potatoes is an important soil-borne disease of potatoes, with reported yield losses exceeding 40%. It is caused by Verticillium species, most notably Verticillium dahliae. Symptoms include leaf chlorosis, limp and flaccid leaves, stunted growth, vascular discoloration towards the stem base, and discoloration of the vascular ring of the tuber. Infection may lead to premature plant decline 4-6 weeks before natural senescence, a condition known as potato early dying. While early dying can occur due to Verticillium alone, symptom severity may increase with co-infection by Pectobacterium spp. or plant-parasitic nematodes. Early dying can also be caused by Colletotrichum coccodes and nutritional deficiencies in the absence of Verticillium. The objective of this guide is to provide detailed information on methods related to disease diagnosis, including isolation, morphological and molecular identification, pathogen detection, isolate storage, and pathogenicity testing for verticillium wilt of potatoes.

Mitogen-activated protein kinase kinase kinases (MAPKKKs) are pivotal upstream regulators of MAPK cascades, integrating signals that coordinate plant development and stress responses. However, the specific functions of MAPKKKs, particularly within the MEKK subfamily, in mediating cotton resistance to Verticillium wilt and Fusarium wilt remain poorly characterized. To address this, we conducted a systematic, cross-species analysis of the MAPKKK family in four key cotton species: Gossypium arboreum, Gossypium barbadense, Gossypium hirsutum, and Gossypium raimondii. Genome-wide identification and phylogenetic analysis revealed 660 MAPKKK genes, classifying them into the MEKK, Raf, and ZIK subfamilies. Evolutionary analysis indicated that Whole-Genome Duplication (WGD) events were the primary driver of family expansion. Promoter cis-element and Gene Ontology (GO) enrichment analyses implicated these genes in hormone signaling and stress adaptation. Expression profiling demonstrated functional modularity, with distinct members responding specifically to cold stress or cooperatively to drought and salt stresses. Upon pathogen infection, members diverged into regulatory modules associated with immune homeostasis, tissue-specific defense, and core signaling potentially governing systemic acquired resistance (SAR). The temporal expression patterns of core candidate genes were validated by qRT-PCR. This study provides, for the first time, a comprehensive evolutionary and functional framework for the MEKK subfamily within the cotton MAPKKK family. It reveals the conserved and divergent roles of this subfamily in stress adaptation and identifies key candidate genes for breeding disease-resistant cotton varieties.

Verticillium wilt (VW) of cotton caused by the soilborne pathogen Verticillium dahliae is a major disease across cotton production worldwide. The disease can result in yield reductions up to 80% on some occasions. V. dahliae is an asexual fungus and belongs to a relatively small Verticillium genus in the Ascomycota, though both of the mating type idiomorphs are present within some populations. The diversity of V. dahliae is widely associated with vegetative compatibility groups (VCGs), of which six different VCGs are recognised. Of these, isolates belonging to VCGs 1, 2, and 4 are globally distributed and associated with a broad host range, including cotton. Approximately 400 plant species have been recorded as hosts of V. dahliae. The pathogenicity and virulence of V. dahliae in many cases are correlated with VCG designations and hosts of origin. Disease management of VW of cotton still relies on accurate, rapid detection and quantification of V. dahliae using both conventional and molecular approaches. The use of resistant cultivars is the most effective and economical control strategy; however, no cultivars confer complete resistance to the disease. Control strategies including cultural, biological, chemical, and induced-resistance approaches have indicated certain degrees of success in minimising disease damage and diminishing the build-up of pathogen inoculum. In this review, we discuss insights into the VW disease of cotton, and the associated pathogen and current control approaches, as well as future research perspectives.

Verticillium wilt (VW), caused by Verticillium dahliae (Vd), is a major threat to cotton production worldwide. Wall-associated receptor-like kinases (WAKLs) arecritical for plant-environment communication and fungal pathogen resistance, yet their regulatory mechanisms in cotton remain unclear. Through genomic and transcriptomic analysis, coupled with disease resistance assays, we identifieda WAKL gene from Gossypium barbadense acc. Hai7124, named GbWAKL20, was involved in VW resistance. GbWAKL20 was significantly induced upon Vd infection. Silencing GbWAKL20 in Hai7124 compromised VW resistance, suppressed the mitogen-activated protein kinase (MAPK) cascade and salicylic acid (SA) signaling pathway, whereas its ectopic overexpression in Arabidopsis enhanced immune responses. Upon sensing extracellular stress signals at the plasma membrane, GbWAKL20 accumulates and transmits these signals to the nucleus via endoplasmic reticulum-mediated Golgi vesicle transport. GbWAKL20 interacts with the transcription factor GbNFYB8 and promotes its nuclear translocation through phosphorylation. GbNFYB8 binds to CCAAT elements in promoters of immunity-related genes and activates their expression. Silencing GbNFYB8 reduces VW resistance in cotton. GbWAKL20-mediated phosphorylation enhances transcriptional activation activity of GbNFYB8, further amplifying disease resistance responses and improving plant resistance. Our results highlight the significance of the GbWAKL20-GbNFYB8 module in defending against VW and provide novel insights into plant immune signaling pathways.

Verticillium wilt, caused by Verticillium dahliae, is a major disease affecting California strawberry production. Following the phase out of methyl bromide, an integrated approach is necessary to alleviate disease pressure. Two field experiments were conducted to evaluate the integration of sequential fumigant applications, crop termination and bed fumigation, and a moderately resistant cultivar on disease incidence and yields. Crop termination utilized metam potassium or metam sodium; bed fumigation utilized either of the metam products or chloropicrin. ‘Seascape’ and ‘Valiant’ were utilized to evaluate the integration of genetic resistance following fumigation. In both trials, total and marketable yields were statistically similar between plots that were only bed fumigated and those sequentially crop terminated and bed fumigated. In trial 1, where initial V. dahliae inoculum and disease pressure were high, sequential crop termination with metam potassium followed by bed fumigation with chloropicrin produced the highest average total (21.8 ± 0.7 kg) and marketable (16.4 ± 0.7 kg) yields and significantly reduced disease incidence compared with the non-treated control. In contrast, trial 2 exhibited lower overall disease incidence due to reduced inoculum levels and cooler, wetter conditions; no significant yield differences were observed among treatments. Across both trials, ‘Seascape’ produced higher average total yields than ‘Valiant’, and cultivar resistance did not consistently reduce disease incidence. These results indicate that fumigation remains most effective under high inoculum conditions, whereas the benefit of additional crop termination or genetic resistance is diminished under low disease pressure.

Suppressing an AUX/IAA gene GhIAA43 expression activates the SA-mediated immune pathway and enhances Verticillium wilt resistance in cotton.

New cultivars resistant to Verticillium wilt obtained in the olive breeding program of IFAPA in Córdoba, Spain

Natural spread of Verticillium wilt as effective constraint on Ailanthus altissima invasion

Verticillium wilt (VW) severely limits the cotton yield and fiber quality. Marker-assisted selection is an efficient strategy for breeding resistant varieties. In this study, a high-density genetic map was constructed by using an F8:9 recombinant inbred line (RIL) population derived from CCRI70. Phenotypic data on disease incidence (DINC) and disease index (DI) were collected across six environments. A total of 59 QTLs for DINC and 60 QTLs for DI were identified, with three and six stable across multiple environments, respectively. These QTLs formed 18 clusters across 13 chromosomes, showing consistent additive effects. Transcriptome analysis revealed eight differentially expressed candidate genes within stable QTL regions. Among them, GH_D05G1495, GH_A09G1013, and GH_D05G1683 were further validated by virus-induced gene silencing as key genes conferring V. dahliae resistance in cotton. This study provides valuable genetic resources for improving Verticillium wilt resistance in cotton breeding.

Comparative omics analysis offers one of the most direct and effective approaches to gain novel insights into crop traits, facilitating candidate gene identification and crop improvement. Verticillium dahliae causes one of the most globally devastating crop diseases, the Verticillium wilt (VW). However, comparative transcriptome resources regarding VW resistance remain scarce in a major host species potato. To address this knowledge gap, we provide a comprehensive comparative RNA-seq analysis of VW resistance between a VW-resistant and -susceptible potato cultivar (LS8 and SP, respectively). VW inoculation induced dramatic transcriptomic changes, resulting in 14,310 differentially expressed genes (DEGs) in LS8 and 21,739 DEGs in SP. With the time-series analysis, we disentangled the VW-associated transcriptomic responses from those reflected LS8-SP cultivar differences. Particularly, LS8 featured a rapid response of phytohormone salicylic acid and defense-related specialized metabolites at 1 day post inoculation (dpi), followed by large-scale metabolic reprogramming, including carbohydrate and choline metabolism and enhanced biosynthesis of secondary cell wall components (e.g., hemicellulose, xylan, cuticle, suberin, and wax). Furthermore, we identified highly expressed VW-responsive potato phenylalanine ammonia-lyase genes (StPALs) and revealed the higher PAL activities in LS8 associated with VW resistance. Overall, our results provide the first transcriptomic insights into VW resistance in potato and new candidate genes regarding VW resistance.

Verticillium wilt is an emerging threat to Brassicaceae crops worldwide, yet information on the species diversity and pathogenicity of Verticillium on Napa cabbage (Brassica rapa subsp. pekinensis) in South Korea remains limited. During surveys in 2020 and 2021, patches of wilted Napa cabbage plants were observed in highland cultivation regions, with disease incidence ranging from 1 to 10%. Twenty symptomatic plants were collected, and fifteen fungal isolates were obtained through tissue culture. Morphological observations and multilocus phylogenetic analyses based on four loci (ACT, EF, GPD, and TS) identified two species, V. dahliae and Verticillium longisporum (lineages A1/D1). Morphologically, V. longisporum produced longer conidia (>6.1 μm) and elongate microsclerotia, whereas V. dahliae produced shorter conidia (<6.0 μm) and spherical microsclerotia. Growth assays demonstrated that V. longisporum grew optimally at 22 °C and V. dahliae at 25 °C, with V8 agar supporting the best growth of both species. Pathogenicity tests on Napa cabbage seedlings confirmed that both species caused typical wilt symptoms, including leaf yellowing, senescence, and stunted growth. To our knowledge, this is the first report of V. longisporum associated with Verticillium wilt of Napa cabbage in South Korea. While Verticillium wilt has so far been confined to highland cultivation areas, considering the predominance of V. longisporum in autumn–winter cropping regions in Japan, continued monitoring in similar Korean production regions will be essential. These findings provide new insights into the distribution, morphology, and pathogenicity of Verticillium species, contributing to the development of effective management strategies for Napa cabbage production.

Phloem protein 2 (PP2) performs a vital function in plant stress response. Verticillium wilt is a destructive vascular disease that leads to significant reductions in cotton yield. However, limited systematic investigation has been conducted on the responsiveness of PP2 to V. wilt in cotton. Here, we identified a total of 46 GhPP2s from the genome of Gossypium hirsutum. Among them, 41 GhPP2s exhibited differentially expression during infection by Verticillium dahliae, with an AtPP2-A1 homologue, GhPP2-43 displaying a pronounced response, indicating their potential roles in V. wilt resistance. Furthermore, GhPP2-43 may interact with peroxidase GhPER24 and ribosomal protein L18 (GhRPL18), potentially serving as a key regulator for enhancing cotton's defense to V. wilt by improving a burst of reactive oxygen species (ROS) and its involvement in phytohormone signaling pathways. These findings offer valuable insights into GhPP2s and indicate potential molecular targets for improving resistance against V. wilt in cotton.

The soil-borne fungus Verticillium dahliae is a devastating pathogen responsible for substantial losses in cotton production. This study elucidated the key functions of VdARO2 and VdCPC1 in fungal pathogenicity. VdARO2 encodes a Chalmoic acid synthase involved in the biosynthesis of aromatic amino acids, while VdCPC1 is a central regulator of amino acid starvation response and reveals a key regulatory relationship between VdARO2 and VdCPC1 to jointly control fungal virulence. We demonstrate that both genes are essential for growth, conidiation, and microsclerotia formation in V. dahliae. The VdΔaro2 mutant exhibited severe developmental defects and a complete loss of microsclerotia production, accompanied by widespread transcriptional dysregulation. Disruption of VdARO2 significantly upregulated VdCPC1, triggering a compensatory starvation response that nonetheless failed to restore pathogenicity. Silencing VdCPC1 similarly impaired fungal development and attenuated virulence. Our findings reveal a crucial regulatory axis in which VdARO2 and VdCPC1 coordinate metabolic homeostasis and stress adaptation to facilitate host colonization, thereby identifying promising targets for the control of Verticillium wilt.

Abstract Ailanthus altissima (tree of heaven) is an invasive tree that inhibits regeneration of forests. Management of forests invaded by A. altissima often includes chemically treating it and leaving dead boles behind. Verticillium nonalfalfae (Verticillium wilt) infects some populations of A. altissima leading to localized mortality. Areas with population-wide A. altissima mortality may increase as this disease spreads or is used as a biocontrol agent. Ailanthus altissima has documented allelopathic compounds; stems left to decompose may result in soil legacy effects that negatively impact native plant restoration. The goal of this study was to determine if soil under decomposing A. altissima wood has negative impacts on native perennial plant germination and growth. Ailanthus altissima was grown in a garden for four years, basally cut, and treated with herbicide. The stems were sectioned and stacked into piles to decompose for 18 months on grass and garden fabric, after which the wood was mulched. Soil from cores taken under each wood pile was added over potting media in pots in which seeds of three native perennials ( Echinacea purpurea , Apocynum cannabinum , and Boehmeria cylindrica ) were planted. Seeds for half the pots were covered with potting media or mulch, respectively. The plants were grown under high- and low-light conditions in a greenhouse for three months. Germinations were tallied and dry shoot biomass was determined. Pots with wood-pile soil had lower germination and biomass production for two of the native species, but mulch reduced the impact. Biomass was greater for all soil treatments with mulch added compared to treatments with no mulch. Plants growing in soil under garden fabric had germination values similar to plants in wood-pile soil. This study reveals that soil under decomposing A. altissima wood is likely to negatively impact germination and growth of some newly seeded species for at least 18 months.

First Report Worldwide of Verticillium Wilt of Fennel Caused by <i>Verticillium dahliae</i>

Verticillium wilt, caused by the soil-borne plant pathogenic fungus Verticillium dahliae, poses a major threat to agriculture, affecting over 400 plant species globally. This study aims to characterize environmental correlates of the occurrence of V. dahliae infections in Andalusia, southern Spain, and to estimate its current and future potential distribution. Data derived from 15 years of active monitoring of Verticillium wilt in olive and cotton were analyzed using two complementary modeling approaches including general linear models using presence/absence records to model occurrence probability, and maximum entropy modeling using presence/background records to explore environmental suitability. Temperature and precipitation variables were key factors in the models, while soil texture and landscape features (i.e., slope and solar radiation) contributed to a lesser extent. Projections of suitability to landscapes in southern Spain under future climate scenarios anticipate a shift in suitable areas towards the southern and southeastern parts of Andalusia, driven by rising temperatures and changing precipitation patterns. None of the models projected a decrease in suitability for the pathogen in the region. These findings provide valuable insights for Integrated Disease Management (IDM) strategies, emphasizing the importance of avoidance and exclusion of the pathogen using pathogen-free certified planting material and selecting locations to establish new plantations based on soil phytosanitary status and pathogen risk. Our results underscore the utility of ecological niche models to predict disease occurrence and spread.

Verticillium wilt, caused by Verticillium dahliae, is a serious vascular wilt disease in cotton (Gossypium spp.). However, the roles and mechanisms of cotton gland formation (CGF) genes in regulating cotton V. dahliae resistance remain elusive. Virus-induced gene silencing or CRISPR-/Cas9-mediated knockdown or knockout of GbCGF2/3 decreases cotton resistance to Verticillium wilt. RNA-sequencing (RNA-seq) shows lower transcript levels of the suberin biosynthetic gene fatty acyl-coenzyme A reductase 3.1 (FAR3.1) in GbCGF2/3-silenced cotton plants. Silencing or knocking out GbFAR3.1 impairs cotton resistance to V. dahliae and decreases suberin compositional monomer fatty acids (C16-C24) contents. GbCGF2/3 positively regulates GbFAR3.1 expression by binding to its promoter. Suberin deposition in the lamellae layer of the root cell wall decreases significantly in GbCGF2/3 Cas9-mediated knockout and GbFAR3.1-silenced cotton plants. Additionally, the expression of gossypol biosynthetic genes and defense-related genes PDF1.2 and PR4 in the phytohormone jasmonic acid (JA) pathway is also downregulated in GbCGF2/3-silenced or Cas9-mediated knockout plants. In conclusion, GbCGF2/3 positively regulates Verticillium wilt resistance through promoting suberin biosynthesis, gossypol accumulation and expression of JA signaling defense-related genes, providing a novel insight and strategy for breeding cotton cultivars resistant to Verticillium wilt.

The article presents data on the effect of applying composts prepared from cattle manure and various types of organic and mineral waste to the soil, which reduces the level of damage to cotton plants by verticillium wilt, and on the phytosanitary condition of the soil, which improves with an increase in the amount of organic matter in the soil, and reduces plant diseases.

Development of a new method for characterizing olive cultivar resistance to Verticillium dahliae, the causal agent of Verticillium wilt