Over the last several decades, kiwifruit production has been severely damaged by the bacterial plant pathogen Pseudomonas syringae pv. actinidiae (Psa), resulting in severe economic losses worldwide. Currently, copper bactericides and antibiotics are the main tools used to control this bacterial disease. However, their use is becoming increasingly ineffective due to the emergence of antibiotic resistance. In addition, environmental issues and the changes in the composition of soil bacterial communities are also concerning when using these substances. Although biocontrol methods have shown promising antibacterial effects on Psa infection under in vitro conditions, the efficiency of antagonistic bacteria and fungi when deployed under field conditions remains unclear. Therefore, it is crucial to develop a phage-based biocontrol strategy for this bacterial pathogen. Due to the specificity of the target bacteria and for the benefit of the environment, bacteriophages (phages) have been widely regarded as promising biological agents to control plant, animal, and human bacterial diseases. An increasing number of studies focus on the use of phages for the control of plant diseases, including the kiwifruit bacterial canker. In this review, we first introduce the characteristics of the Psa-induced kiwifruit canker, followed by a description of the diversity and virulence of Psa strains. The main focus of the review is the description of recent advances in the isolation of Psa phages and their characterization, including morphology, host range, lytic activity, genome characterization, and lysis mechanism, but we also describe the biocontrol strategies together with potential challenges introduced by abiotic factors, such as high temperature, extreme pH, and UV irradiation in kiwifruit orchards. The information presented in this review highlights the potential role of phages in controlling Psa infection to ensure plant protection.

Bacterial panicle blight of rice or bacterial grain rot of rice is a worldwide rice disease. Burkholderia glumae and B. gladioli are the causal agents. The early and accurate detection of seed-borne B. glumae and B. gladioli is critical for domestic and international quarantine and effective control of the disease. Here, genomic analyses revealed that B. gladioli contains five phylogroups and the BG1 primer pair designed to target the 3’-end sequence of a gene encoding a Rhs family protein is specific to B. glumae and two phylogroups within B. gladioli. Using the BG1 primer pair, a 138-bp DNA fragment was amplified only from the tested panicle blight pathogens B. glumae and B. gladioli. An EvaGreen droplet digital PCR (dPCR) assay on detection and quantification of the two pathogens was developed from a SYBR Green real-time quantitative PCR (qPCR). The detection limits of the EvaGreen droplet dPCR on the two pathogens were identical at 2 × 10³ colony forming units (CFU)∙mL⁻¹ from bacterial suspensions and 2 × 10² CFU∙seed⁻¹ from rice seeds. The EvaGreen droplet dPCR assay showed 10-fold detection sensitivity of the SYBR Green qPCR and could detect a single copy of the target gene in a 20-μL assay. Together, the SYBR Green qPCR assay allows for routine high-throughput detection of the panicle blight pathogens and the EvaGreen droplet dPCR assay provides a high-sensitive and high-accurate diagnostic method for quarantine of the pathogens.

Biofilm formation is important for virulence of a large number of plant pathogenic bacteria. Indeed, some virulence genes have been found to be involved in the formation of biofilm in bacterial fruit blotch pathogen Acidovorax citrulli. However, some virulent strains of A. citrulli were unable to format biofilm, indicating the complexity between biofilm formation and virulence. In this study, virulence-related genes were identified in the biofilm-defective strain A1 of A. citrulli by using Tn5 insertion, pathogenicity test, and high-efficiency thermal asymmetric interlaced PCR (hiTAIL-PCR). Results from this study indicated that 22 out of the obtained 301 mutants significantly decreased the virulence of strain A1 compared to the wild-type. Furthermore, sequence analysis indicated that the obtained 22 mutants were due to the insertion of Tn5 into eight genes, including Aave 4244 (cation diffusion facilitator family transporter), Aave 4286 (hypothetical protein), Aave 4189 (alpha/beta hydrolase fold), Aave 1911 (IMP dehydrogenase/GMP reductase domain), Aave 4383 (bacterial export proteins, family 1), Aave 4256 (Hsp70 protein), Aave 0003 (histidine kinase, DNA gyrase B, and HSP90-like ATPase), and Aave 2428 (pyridoxal-phosphate dependent enzyme). Furthermore, the growth of mutant Aave 2428 was unaffected and even increased by the change in incubation temperature, NaCl concentration and the pH of the LB broth, indicating that this gene may be directly involved in the bacterial virulence. Overall, the determination of the eight pathogenicity-related genes in strain A1 will be helpful to elucidate the pathogenesis of biofilm-defective A. citrulli.

Gram-negative Burkholderia bacteria are known for causing diseases in humans, animals, and plants, and high intrinsic resistance to antibiotics. Phage therapy is a promising alternative to control multidrug-resistant bacterial pathogens. Here, we present an overview of Burkholderia phage characteristics, host specificity, genomic classification, and therapeutic potentials across medical, veterinary, and agricultural systems. We evaluate the efficacy and limitations of current phage candidates, the biological and environmental barriers of phage applications, and the phage cocktail strategy. We highlight the innovations on the development of targeted phage delivery systems and the transition from the exploration of clinical phage therapy to plant disease management, advocating integrated disease control strategies.

Bulb rot is one of the most destructive diseases of tulip (Tulipa gesneriana L.). In November 2022, rotten tulip bulbs and terminal buds were found in Songjiang District, Shanghai, China. Fungal isolates were isolated from the rotten bulbs and identified as Fusarium based on colony morphology and ITS sequences. Further analyses of tef1, rpb1, and rpb2 barcoding sequences and conidial micromorphology identified the Fusarium isolates as F. annulatum. The pathogenicity of the F. annulatum isolates was verified with Koch’s postulates. This is the first report of F. annulatum causing bulb rot disease of tulip.

The red imported fire ant (RIFA), Solenopsis invicta, is a globally invasive pest that causes substantial ecological, agricultural, and public health challenges. Conventional control strategies primarily depend on chemical insecticides, which present environmental risks and limited long-term efficacy. In this study, we comprehensively investigated the bacterial microbiota of S. invicta and compared it with a sympatric non-target ant species (Pheidole nodus) to explore the ecological significance and biocontrol potential of symbiotic bacteria. High-throughput 16S rRNA sequencing revealed that the symbiotic bacterial community of S. invicta exhibited markedly higher richness and diversity. A total of 1651 amplified sequence variants (ASVs) were identified, of which 1089 ASVs are unique to the RIFAs, and 460 are unique to non-target ants. Linear discriminant analysis effect size (LEfSe) highlighted 33 biomarker taxa (score > 6.5), with strong enrichment of Stenotrophomonas, Serratia, Pseudomonas, Luteibacter, Bradyrhizobium, Brucella, Smaragdicoccus, Gordonia, and Aeromonas. Functional predictions and enzymatic assays in vitro demonstrated that dominant cultivable genera, particularly Stenotrophomonas (SI-7, SI-17), Serratia (SI-1, SI-3, SI-6, SI-18), and Pseudomonas (SI-2, SI-8, SI-9, SI-11, SI-19), exhibit substantial proteolytic and lipolytic activity, suggesting key roles in nutrient metabolism and host ecological adaptability. Antibiotic susceptibility profiling further revealed that florfenicol shows broad-spectrum inhibitory activity against these dominant symbionts. These findings indicate that disrupting dominant symbiotic bacteria may impair host physiology and thus serve as a targeted control strategy. Overall, the study elucidates the diversity, functional potential, and biocontrol applicability of the S. invicta microbiome, providing a foundation for developing sustainable, microbiome-based pest management approaches.