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Fusarium wilt of banana (FWB), caused by the soil-borne fungus Fusarium oxysporum f. sp. cubense (Foc), poses an undeniable threat to global banana production. This disease has intensified in recent years, with the tropical race 4 (TR4) strain spreading rapidly. Since 2018, the number of affected countries has increased from 16 to 23, presenting a significant challenge to researchers, producers, and National Plant Protection Organizations (NPPOs) worldwide. The potential impact of TR4 in Latin America and the Caribbean (LAC) is particularly concerning. This region boasts seven of the top ten banana-exporting countries, and bananas and plantains are crucial for food security and income generation. In Colombia, where TR4was detected in 2019, the disease has already spread fromLa Guajira to Magdalena, and it is currently affecting 20 large commercial export farms. In Peru, the disease was detected in 2021 and although still restricted to the northern region, flood irrigation and heavy rains associated with the Yaku cyclone, boosted pathogen spread, and more than 400 small organic banana farmers are currently affected. In Venezuela, TR4 detection occurred in 2023, with plantations across three states and five municipalities now affected. Worryingly, TR4 has also been confirmed in plantains, a staple food in the region. Current national responses in LAC primarily rely on preventive and reactive measures: preventing initial incursions and containing outbreaks to avoid further spread. However, the disease's relentless progression suggests that its eventual presence in all banana-producing areas is likely. Therefore, exploring alternative management approaches beyond pathogen exclusion becomes crucial, both in affected and disease-free regions. This paper examines the current spread of TR4, focusing on epidemiological aspects and recent research-based management options. Key epidemiological features were highlighted, drawing practical examples from various scales (plots to landscapes) and utilizing experiences from LAC's fight against TR4. The paper also reviews field-tested approaches in biosecurity, biological control, resistant varieties, soil health, and integrated disease management, acknowledging the specific challenges faced by smallholder settings. In each section research initiatives were analyzed, identifying gaps, and proposing directions to minimize TR4 impact and accelerate the development of sustainable solutions for managing this devastating disease. [ABSTRACT FROM AUTHOR]

Fusarium wilt of banana (FWB), caused by the soil-borne fungus Fusarium oxysporum f. sp. cubense (Foc), poses an undeniable threat to global banana production. This disease has intensified in recent years, with the tropical race 4 (TR4) strain spreading rapidly. Since 2018, the number of affected countries has increased from 16 to 23, presenting a significant challenge to researchers, producers, and National Plant Protection Organizations (NPPOs) worldwide. The potential impact of TR4 in Latin America and the Caribbean (LAC) is particularly concerning. This region boasts seven of the top ten banana-exporting countries, and bananas and plantains are crucial for food security and income generation. In Colombia, where TR4 was detected in 2019, the disease has already spread from La Guajira to Magdalena, and it is currently affecting 20 large commercial export farms. In Peru, the disease was detected in 2021 and although still restricted to the northern region, flood irrigation and heavy rains associated with the Yaku cyclone, boosted pathogen spread, and more than 400 small organic banana farmers are currently affected. In Venezuela, TR4 detection occurred in 2023, with plantations across three states and five municipalities now affected. Worryingly, TR4 has also been confirmed in plantains, a staple food in the region. Current national responses in LAC primarily rely on preventive and reactive measures: preventing initial incursions and containing outbreaks to avoid further spread. However, the disease’s relentless progression suggests that its eventual presence in all banana-producing areas is likely. Therefore, exploring alternative management approaches beyond pathogen exclusion becomes crucial, both in affected and disease-free regions. This paper examines the current spread of TR4, focusing on epidemiological aspects and recent research-based management options. Key epidemiological features were highlighted, drawing practical examples from various scales (plots to landscapes) and utilizing experiences from LAC’s fight against TR4. The paper also reviews field-tested approaches in biosecurity, biological control, resistant varieties, soil health, and integrated disease management, acknowledging the specific challenges faced by smallholder settings. In each section research initiatives were analyzed, identifying gaps, and proposing directions to minimize TR4 impact and accelerate the development of sustainable solutions for managing this devastating disease.

Fusarium wilt of banana is a devastating disease that has decimated banana production worldwide. Host resistance to Fusarium oxysporum f. sp. Cubense (Foc), the causal agent of this disease, is genetically dissected in this study using two Musa acuminata ssp. Malaccensis segregating populations, segregating for Foc Tropical (TR4) and Subtropical (STR4) race 4 resistance. Marker loci and trait association using 11 SNP-based PCR markers allowed the candidate region to be delimited to a 12.9 cM genetic interval corresponding to a 959 kb region on chromosome 3 of 'DH-Pahang' reference assembly v4. Within this region, there was a cluster of pattern recognition receptors, namely leucine-rich repeat ectodomain containing receptor-like protein kinases, cysteine-rich cell-wall-associated protein kinases, and leaf rust 10 disease-resistance locus receptor-like proteins, positioned in an interspersed arrangement. Their transcript levels were rapidly upregulated in the resistant progenies but not in the susceptible F2 progenies at the onset of infection. This suggests that one or several of these genes may control resistance at this locus. To confirm the segregation of single-gene resistance, we generated an inter-cross between the resistant parent 'Ma850' and a susceptible line 'Ma848', to show that the STR4 resistance co-segregated with marker '28820' at this locus. Finally, an informative SNP marker 29730 allowed the locus-specific resistance to be assessed in a collection of diploid and polyploid banana plants. Of the 60 lines screened, 22 lines were predicted to carry resistance at this locus, including lines known to be TR4-resistant, such as 'Pahang', 'SH-3362', 'SH-3217', 'Ma-ITC0250', and 'DH-Pahang/CIRAD 930'. Additional screening in the International Institute for Tropical Agriculture's collection suggests that the dominant allele is common among the elite 'Matooke' NARITA hybrids, as well as in other triploid or tetraploid hybrids derived from East African highland bananas. Fine mapping and candidate gene identification will allow characterization of molecular mechanisms underlying the TR4 resistance. The markers developed in this study can now aid the marker-assisted selection of TR4 resistance in breeding programs around the world. [ABSTRACT FROM AUTHOR]

Fusarium wilt or Panama disease poses a great risk to banana production worldwide and is caused by Fusarium oxysporum f. sp. Cubense (Foc). Its tropical race 4 (TR4) is a major problem for Cavendish banana growing areas. Basrai (Dwarf Cavendish) is the major cultivated variety in Pakistan and now recently been reported to be affected by Foc TR4 in certain areas in the Sindh province. To genetically characterize, three independent isolates (P.TH1, P.TH2 and P.Th3) were sampled from different fields in district Thatta and fungus was isolated on potato dextrose agar. The pure fungal isolates were used to establish Koch's postulates by testing their pathogenicity on tissue cultured Cavendish banana. A diagnostic PCR assay was optimized and used to sequence a reported molecular marker for specific detection of Foc TR4 and to sequence 28S-18S ribosomal RNA intergenic spacer region (IGS) from these local isolates. The phylogenetic of Pakistani isolates suggests that they belong to previously characterized lineage V of tropical race 4 of F. oxysporum cubense with 99% bootstrap support and show close relationship with Indonesian and Malaysian Foc TR4 isolates. The rapid spread of this disease in different banana growing areas of the Sindh is alarming and necessitates effective control of this through chemical and biocontrol, if remains unchecked, Foc TR4 can raise havoc to banana industry in Pakistan and would be devastating economically. [ABSTRACT FROM AUTHOR]

This study is the first to adopt a hypothetical approach to establish the influence of the complex endophyte-host interaction on endophyte survival and antifungal expression. Three key interactions were evaluated; (I) influence of host-induced enzymes on endophyte growth (biomass) and colonization, (II) link between endophyte-produced cellulase, their growth and colonization, and (III) the influence of host environment on antifungal expression of endophytes. The interactions with the host were performed using plant slurry (PS) to mimic in planta (host) environment with analysis on interactions evaluated using Pearson correlation coefficients (r). Results revealed that host induced enzymes may be a limiting factor to colonization of endophytes with inverse correlations observed (-0.046 = r = -0.7164). These enzymes may also limit growth of endophyte although, PAL (r = 0.536) and TPC (r = 0.8894) appeared contrary. Results were also suggestive that endophytes produced cellulase to aid in colonization in host plants (r = 0.7073 in PS), and cellulase activities are continuously produced even when growth of endophytes are limited (r = -0.314 in PS). Endophytes are presumed to produce antifungal compounds in planta (r = 0.2760 in PS), and these compounds may be secondary metabolites, which are primarily produced under nutrient-depleted conditions where growth is poor (in host plant). The superior growth of endophytes in synthetic PDB media has an inverse correlation to antifungal activity (r = -0.5129), confirming that secondary metabolites are involved in antifungal activities. This study clearly presents that success of inoculated endophytes in colonizing, growing and expressing antifungal activities is dependent on the host plant. [ABSTRACT FROM AUTHOR]

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Fusarium wilt of banana (Musa spp.), caused by Fusarium oxysporum f. sp. cubense (Foc), is one of the most important banana diseases. Three races (1, 2, 4) of Foc have been identified worldwide, but race 4 (especially tropical race 4, TR4) is the most destructive pathogen and has significant impacts on banana production in Taiwan and Southern China. To characterize the genetic relationship of Foc in these two regions, 55 isolates of Foc, including 18 from Taiwan and 37 from Hainan and Guangdong Provinces, were subjected to pathogenicity tests, race 4-specific polymerase chain reaction (PCR) diagnosis, and amplified fragment length polymorphism (AFLP) analysis. One race 4 isolate from Australia, one race 1 isolate from Philippines, and 10 non-banana F. oxysporum isolates were also included in the study for comparison. Pathogenicity tests indicated that 16 and 21 isolates of Foc from Taiwan and Southern China, respectively, were pathogenic on Cavendish banana and classified as race 4, and the remaining isolates were identified as race 1. PCR amplification with race 4 and tropical race 4-specific primers confirmed that all of the race 4 isolates from Taiwan and Southern China were TR4. AFLP analysis with eight EcoRI-MseI primer combinations clustered the 67 F. oxysporum isolates analyzed into two major groups, one containing all race 4 isolates and the other consisting of race 1 isolates along with the non-banana F. oxysporum isolates. No significant divergence was observed among TR4 isolates from Southern China and Taiwan, suggesting that the TR4 isolates from Southern China might share the same lineage as those from Taiwan. [ABSTRACT FROM AUTHOR]