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Understanding the Development of Compensatory Pathways in a Mutant Malaria Parasite Harbouring Hypomorphic Allele of Plant-Like Kinases
Published on: November 22, 2024
Genetic variation and proliferation-promoting virulence function of thymidine kinase from Paulownia witches' broom
Chuansheng Song1, Dezhi Kong2, Xia Li1
1College of Agricultural and Biological Engineering, Heze University, Heze, 274015, China.
Background:
Paulownia witches' broom disease (PaWB), caused by phytoplasmas, results in economic losses. Thymidine kinase (TDK) is a key enzyme in the deoxythymidine triphosphate (dTTP) synthesis pathway of phytoplasma, and dTTP serves as an essential precursor for DNA replication during cell proliferation, but its role in regulating phytoplasma proliferation and virulence remains unclear.
Results:
To characterize the role of TDK in phytoplasma proliferation and virulence, in this study, two PaWB phytoplasma tdk genotypes were identified via sampling in China, and tdk-1 was the most widely distributed. Phylogenetic analysis revealed that single-copied tdk exhibited higher phylogenetic resolution than 16S rRNA for phytoplasma molecular classification. In silico prediction showed that TDK functions as a thymidine kinase in these phytoplasmas. Furthermore, TDK protein expression was detected in PaWB-infected tissues. Immunofluorescence microscopy showed that TDK co-localized with phytoplasmas in sieve tube elements. Immunoelectron microscopy showed that TDK mainly localized in dividing phytoplasma cells. Absolute quantitative analysis revealed that tdk mRNA expression was positively associated with phytoplasma proliferation. Overexpressing tdk in Pseudomonas syringae pv. tomato (Pst) DC3000 significantly enhanced bacterial growth and increased its virulence in Arabidopsis.
Conclusions:
Overall, these results identify phytoplasma TDK as a critical proliferation-associated pathogenicity factor that promotes pathogen proliferation, providing a potential molecular target for controlling PaWB.
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