Polydimethylsiloxane-polymethacrylate block copolymers containing quaternary ammonium salts against Fusarium oxysporum f. sp. cubense race 4 in soil: Antifungal activities and pot experiments

Fusarium Tropical Race 4 in Latin America and the Caribbean: status and global research advances towards disease management

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.

A smooth vetch (Vicia villosa var.) strain endogenous to the broad-spectrum antagonist Bacillus siamensis JSZ06 alleviates banana wilt disease

Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense Tropical Race 4 (Foc TR4), poses a significant threat to banana production globally, thereby necessitating effective biocontrol methods to manage this devastating disease. This study investigates the potential of Bacillus siamensis strain JSZ06, isolated from smooth vetch, as a biocontrol agent against Foc TR4. To this end, we conducted a series of in vitro and in vivo experiments to evaluate the antifungal activity of strain JSZ06 and its crude extracts. Additionally, genomic analyses were performed to identify antibiotic synthesis genes, while metabolomic profiling was conducted to characterize bioactive compounds. The results demonstrated that strain JSZ06 exhibited strong inhibitory activity against Foc TR4, significantly reducing mycelial growth and spore germination. Moreover, scanning and transmission electron microscopy revealed substantial ultrastructural damage to Foc TR4 mycelia treated with JSZ06 extracts. Genomic analysis identified several antibiotic synthesis genes, and metabolomic profiling revealed numerous antifungal metabolites. Furthermore, in pot trials, the application of JSZ06 fermentation broth significantly enhanced banana plant growth and reduced disease severity, achieving biocontrol efficiencies of 76.71% and 79.25% for leaves and pseudostems, respectively. In conclusion, Bacillus siamensis JSZ06 is a promising biocontrol agent against Fusarium wilt in bananas, with its dual action of direct antifungal activity and plant growth promotion underscoring its potential for integrated disease management strategies.

[Determination of two quaternary ammonium salts in disinfector by portable capillary electrophoresis device based on smartphone]

现有的小型毛细管电泳(CE)装置仍采用平板或计算机进行数据处理和分析,其便携性仍存在明显不足。针对这一问题,发展了一种基于智能手机的CE装置,实现了真正的便携式定量分析。该装置集成了电容耦合式非接触式电导检测(C⁴D)和蓝牙通信功能,并提供了手机界面软件。通过手机界面软件,不仅可以控制CE装置的电泳运行,还可以实时接收C⁴D检测器发出的数据信息,显示电泳图谱和进行数据处理。该装置尺寸为20 cm×20 cm×15 cm,重量为2 kg。为了验证所设计装置的性能,采用季铵盐(QAs)消毒剂(十二烷基二甲基苄基溴化铵(DDBAB)和十二烷基三甲基溴化铵(DTAB))作为分析对象。实验数据表明,DDBAB和DTAB线性范围分别为20~1000和30~1000 μmol/L,线性回归方程的相关系数(R²)分别为0.9995和0.9989,检出限(LOD)分别为10和13 μmol/L,日内相对标准偏差(RSD, n=3)分别为1.9%和2.7%。另外实验对DDBAB和DTAB混合离子液进行了测试,在8 min内可实现基线分离。最后,对现场使用的新洁尔灭消毒液中QAs进行了加标回收试验,DDBAB和DTAB的回收率分别为100.5%~101.5%和96.2%~99.3%。研究结果表明,所开发CE装置具有线性好、LOD低、重复好、准确性高,尤其便携好等优点,可用于消毒液中QAs现场定量检测。