Fusarium basal rot caused by Fusarium oxysporum is a major soil-borne disease limiting onion production worldwide. Although Bacillus spp. have been widely investigated as biological control agents against Fusarium diseases, field-level validation and genomic characterization of biocontrol-associated traits remain limited. In this study, two onion-associated B. cereus strains, 23-046 and 23-052, were subjected to whole-genome sequencing to characterize their genomic features, and strain 23-046 was additionally evaluated for suppression of Fusarium occurrence under field conditions. The field experiments were conducted using soil drench application at the seedling-stage, soil incorporation, and combined application. Soil incorporation significantly reduced Fusarium recovery compared with seedling-stage soil drench application. In contrast, bulb height and bulb weight were not significantly affected by bacterial treatments, whereas sheath diameter significantly increased following soil incorporation, indicating improved vegetative growth without negative effects on bulb development. Complete genome sequencing using PacBio platforms revealed that strains 23-046 and 23-052 possessed circular chromosomes of 5.31 Mb and 5.45 Mb, respectively, while strain 23-052 additionally harbored a 456-kb plasmid enriched in genes associated with transcriptional regulation, defense mechanisms, and mobilome-related functions. Comparative genomic analyses identified multiple biosynthetic gene clusters associated with siderophore production and nonribosomal peptide synthetase pathways. These results presented the potential of B. cereus strain 23-046 for suppression of onion Fusarium basal rot under field conditions and show that strains 23-046 and 23-052 harbor biosynthetic gene clusters.
Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), threatens global wheat production. Pakistan lies within the Himalayan epidemiological zone, a major center of Pst diversity and migration, making pathogen characterization essential for disease management and regional early-warning systems. This study characterized 277 Pst isolates collected from Pakistan’s major wheat-growing regions during 2012–2017 using 18 Yr single-gene differential lines. Overall, 127 races were identified, including 103 transient races detected in one year and 24 persistent races found across multiple years, indicating substantial virulence diversity. Virulence was widespread against Yr1, Yr6, Yr7, Yr8, Yr9, Yr17, Yr27, Yr43, Yr44, and YrExp2, reflecting adaptation to widely deployed resistance genes. In contrast, virulence against Yr10, Yr15, Yr24, Yr32, YrSP, and YrTye/Yr76 was limited or geographically restricted, while no virulence was detected against Yr5, confirming its continued effectiveness. Multivariate analyses revealed non-random phenotypic virulence patterns. Four principal components explained 57.56% of total variation and captured major infection type responses to defeated and effective resistance sources. Discriminant analysis grouped isolates into two broad virulence classes, demonstrating phenotypic structuring rather than genotypic lineage subdivision. The coexistence of common and rare profiles suggests a dynamic pathogen population shaped by local selection and regional movement. These findings highlight the need for continuous surveillance, integrated phenotypic and molecular monitoring, and strategic deployment of diverse resistance genes to support durable stripe rust management in Pakistan and the wider region through coordinated national and regional research networks.
This study investigated the occurrence of yellowing viruses in Korean cucurbit crops and developed a multiplex reverse transcription-polymerase chain reaction (RT-PCR) assay for their simultaneous detection. Between 2020 and 2024, symptomatic leaf samples from melon, cucumber, and watermelon were analyzed nationwide. Cucurbit aphid-borne yellows virus (CABYV) and cucurbit chlorotic yellows virus (CCYV) were widely distributed. The average detection rates in symptomatic samples of melon were 48.8% for CABYV and 9.2% for CCYV, and in cucumber, 26.8% for CABYV and 17.1% for CCYV. In watermelon, based on two years of symptomatic sampling, CABYV and CCYV were detected at 5.8% and 6.8%, respectively. Notably, despite a 4.5% national average, melon aphid-borne yellows virus (MABYV) was detected at high rates in symptomatic watermelon samples from Jeonbuk (up to 58.5% in 2023). Because these viruses induce visually indistinguishable symptoms and frequently cause mixed infections, accurate identification is crucial for vector-specific disease management. Therefore, a multiplex RT-PCR assay was developed to simultaneously detect CABYV, CCYV, and MABYV in a single reaction, successfully differentiating single and mixed infections with a detection limit of a 10-3 dilution.
Kimchi cabbage (Brassica rapa subsp. pekinensis) is one of the most important vegetable crops in Korea, playing a crucial role in both agricultural production and the traditional Kimchi industry. However, its production is severely threatened by several bacterial diseases, which can cause significant yield losses and economic damage, particularly under warm, humid conditions and continuous cultivation systems. The most prevalent bacterial diseases affecting Kimchi cabbage in Korea include black rot caused by Xanthomonas campestris pv. campestris (Xcc), soft rot (Pectobacterium spp.), and bacterial leaf spot caused by Pseudomonas syringae pv. maculicola (Psm). These pathogens induce vascular discoloration, tissue maceration, foliar lesions, wilting, and plant collapse, resulting in reduced yield and market quality. Traditional control methods primarily relies on copper-based bactericides and antibiotics; however, their effectiveness is increasingly constrained by the emergence of resistant bacterial populations, limited curative activity, and environmental and regulatory concerns. Consequently, integrated disease management (IDM), incorporating disease-free seed, resistant cultivars where applicable, crop rotation, field sanitation, optimized irrigation, and biological control agents, has emerged as the most sustainable approach for disease suppression. Although considerable progress has been achieved in developing biological control agents and improving integrated management practices, durable and environmentally sustainable control of bacterial diseases remains a major challenge for Kimchi cabbage production in Korea. This review outlines the occurrence, epidemiology, economic impact, diagnosis, and management of major bacterial diseases affecting Kimchi cabbage in Korea and highlights the importance of IDM for sustainable crop production.
This study characterized rust disease associated with Puccinia modiolae on Malva verticillata grown in a plastic greenhouse. The inhibitory effects of four fungicides and a microbial agent containing Bacillus amyloliquefaciens on teliospore germination were also evaluated. Infected leaves showed numerous yellow to yellowish-green chlorotic spots on the adaxial surface and reddish-brown to dark brown telia on the abaxial surface. The teliospores were morphologically characterized as mostly two-celled, divided by a transverse septum, and fusoid to long ellipsoid in shape. They measured 49.2–99.9×12.5–26.6 μm, with a mean size of 76.1×21.0 μm. Phylogenetic analysis based on large subunit (LSU) rDNA sequences supported the identification of the rust fungus as P. modiolae. In vitro, teliospore germination was reduced to 7.6%±3.8%, 7.7%±0.7%, 8.0%±2.8%, and 41.4%±14.3% by azoxystrobin, mancozeb, tebuconazole, and cyazofamid, respectively. The corresponding germination inhibition rates were 91.6%, 91.5%, 91.2%, and 54.4%, respectively. The microbial agent containing B. amyloliquefaciens reduced teliospore germination to 14.6%±5.0%, corresponding to an inhibition rate of 83.9%. These results provide information on the characteristics of rust disease associated with P. modiolae on M. verticillata and on candidate treatments for further disease-control studies. Further studies are needed to evaluate rust disease control under different conditions.
