Generation of Zucchini Tigre Mosaic Virus Mild Strains for Application in Cross-Protection

Area of Science:

• Plant Virology
• Molecular Biology
• Crop Protection

Background:

• Zucchini tigre mosaic virus (ZTMV) was first identified in Taiwan in 2017.
• ZTMV poses a significant threat to cucurbit crops like wax gourd, pumpkin, and zucchini.
• Developing effective disease management strategies for ZTMV is crucial for agricultural productivity.

Purpose of the Study:

• To develop cross-protection strategies for ZTMV using mild strains.
• To investigate the role of the HC-Pro protein in ZTMV pathogenicity.
• To identify specific ZTMV mutants suitable for cross-protection in different cucurbit hosts.

Main Methods:

• Generated a full-length infectious cDNA clone of ZTMV-TW (ZTMV-TWic).
• Mutated conserved motifs within the HC-Pro gene to create single and double mutants.
• Performed cross-protection assays using ZTMV-GFP as the challenge virus in zucchini and wax gourd.

Main Results:

• Mutants R181I and R181I+D397N induced mild or no symptoms in zucchini and provided complete protection against ZTMV-GFP.
• Mutants D397N and F206L+D397N caused mild symptoms in wax gourd and conferred high protection against ZTMV-GFP.
• Demonstrated host-specific efficacy of mild ZTMV strains for cross-protection.

Conclusions:

• Mild ZTMV strains, particularly specific HC-Pro mutants, can be effectively utilized for cross-protection in cucurbit crops.
• Host-specific selection of mild strains is key to successful ZTMV cross-protection strategies.
• This research provides a viable approach for managing ZTMV and safeguarding crop yields.