Author:
Wang Qian,Zhang Yiju,Chen Rui,Zhang Lei,Fu Min,Zhang Lixin
Abstract
Abstract
Background
Pseudomonas syringae pv. actinidiae (Psa) is an important bacterial plant pathogen that causes severe damage to the kiwifruit industry worldwide. Three Psa strains were recently obtained from different kiwifruit orchards in Anhui Province, China. The present study mainly focused on the variations in virulence and genome characteristics of these strains based on the pathogenicity assays and comparative genomic analyses.
Results
Three strains were identified as biovar 3 (Psa3), along with strain QSY6 showing higher virulence than JZY2 and YXH1 in pathogenicity assays. The whole genome assembly revealed that each of the three strains had a circular chromosome and a complete plasmid. The chromosome sizes ranged from 6.5 to 6.6 Mb with a GC content of approximately 58.39 to 58.46%, and a predicted number of protein-coding sequences ranging from 5,884 to 6,019. The three strains clustered tightly with 8 Psa3 reference strains in terms of average nucleotide identity (ANI), whole-genome-based phylogenetic analysis, and pangenome analysis, while they were evolutionarily distinct from other biovars (Psa1 and Psa5). Variations were observed in the repertoire of effectors of the type III secretion system among all 15 strains. Moreover, synteny analysis of the three sequenced strains revealed eight genomic regions containing 308 genes exclusively present in the highly virulent strain QSY6. Further investigation of these genes showed that 16 virulence-related genes highlight several key factors, such as effector delivery systems (type III secretion systems) and adherence (type IV pilus), which might be crucial for the virulence of QSY6.
Conclusion
Three Psa strains were identified and showed variant virulence in kiwifruit plant. Complete genome sequences and comparative genomic analyses further provided a theoretical basis for the potential pathogenic factors responsible for kiwifruit bacterial canker.
Funder
the National Natural Science Foundation of China
Innovation Research and Experiment Program for Youth Scholar
the Natural Science Foundation of Tianjin
the Development Fund for Talent Personnel of Anhui Agricultural University
Publisher
Springer Science and Business Media LLC
Reference71 articles.
1. Leontowicz H, Leontowicz M, Latocha P, Jesion I, Park Y-S, Katrich E, et al. Bioactivity and nutritional properties of hardy Kiwi fruit Actinidia arguta in comparison with Actinidia deliciosa ‘Hayward’and Actinidia eriantha ‘Bidan’. Food Chem. 2016;196:281–91.
2. Fazayeli A, Kamgar S, Nassiri SM, Fazayeli H, de la Guardia M. Dielectric spectroscopy as a potential technique for prediction of kiwifruit quality indices during storage. Inform Process Agric. 2019;6:479–86.
3. FAO-Food and Agriculture Organization of the United Nations. FAOSTAT-Crops and livestock products. (2020).
4. Takikawa Y, Serizawa S, Ichikawa T, Tsuyumu S, Goto M. Pseudomonas syringaepv. actinidiae pv. nov. the causal bacterium of canker of kiwifruit in Japan. Jpn J Phytopathol. 1989;55(4):437–44.
5. Shao X, Wu Q, Li L, He W, He X, Cheng D, et al. Adapting the inoculation methods of kiwifruit canker disease to identify efficient biocontrol bacteria from branch microbiome. Mol Plant Pathol. 2024;25(1):e13399.