Novel insights into the genetic basis and proteotranscriptomic elucidation of virulence attenuation in Pseudomonas syringae pv. actinidiae variants

ABSTRACT: Pseudomonas syringae pv. actinidiae (Psa) is the potential cause of Kiwifruit Bacterial Canker (KBC) but the factors affecting its pathogenicity in natural setting is less elaborated. Here, we isolated two Psa3 strains, G126 and G282, from Guizhou province`s kiwifruit orchards suffering from KBC disease. Both isolates belonging to Psa-biovar 3 were verified by Psa3-specific primers. Compared to Psa3-G1 positive control strain, G282 exhibited significant reduction of necrotic spots and lesion density during pathogenicity assays on kiwifruit leaf discs and branches, while G126 was unable to show any disease phenotype. Similarly, no induction of hypersensitive response in tobacco plants as well as significantly reduced promoter’s activities of hrpA, hrpR/S/L of type III secretion system (T3SS) cascade suggested that both strains are defective in functional T3SS-dependent phenotypes. Genomic sequencing of these strains revealed that T3SS pathway of G126 was defective due to a single-nucleotide polymorphism variation in hrpR gene, while G282 was entirely deprived of T6SS to potentially transmit T3SS effectors. In addition, transcriptomic analysis of GO and KEGG pathways revealed several key aspects related to the secretion system, protein transport and signal transduction being widely affected. This study advances our understanding to the genetic basis of these non-pathogenic and partial pathogenic isolates, and the functional interdependencies between secretion systems (T3SS, T6SS) and metabolic or motility-related pathways, showcasing how genetic mutations lead to widespread physiological changes will provide insights into virulence evolution, the identification of pathogenic determinants, and the development of biocontrol strategies against Psa.

ORGANISM(S): Pseudomonas syringae pv. actinidiae

PROVIDER: GSE286024 | GEO | 2025/01/31

REPOSITORIES: GEO