Squash Yellow Leaf Curl Virus: A New Whitefly-Transmitted Poty-Like Virus

Area of Science:

• Plant Pathology
• Virology
• Agricultural Entomology

Background:

• A severe yellow and leaf curl disease impacting field squash has been identified in Oman's Batinah region.
• Symptoms include yellow spots, veinal yellowing, and leaf curling on young squash leaves.

Purpose of the Study:

• To characterize the virus causing the yellow and leaf curl disease in Omani field squash.
• To determine the virus's transmission methods, host range, and taxonomic relationship to known viruses.

Main Methods:

• Mechanical inoculation and whitefly transmission studies using Bemisia tabaci.
• Host range determination on cucurbit species.
• Electron microscopy of infected tissues and serological analysis using enzyme-linked immunosorbent assay (ELISA).

Main Results:

• The virus was efficiently transmitted mechanically and by the whitefly Bemisia tabaci in a semi-persistent manner.
• The virus exhibited a restricted host range, affecting only two cucurbit species.
• Electron microscopy revealed flexuous particles (700-750 nm) and pinwheel inclusion bodies.
• Serological tests indicated a relationship to watermelon mosaic virus-2, but distinctness from other related viruses.

Conclusions:

• The identified virus represents a newly described pathogen, tentatively named squash yellow leaf curl virus.
• This finding necessitates further research into its epidemiology and control strategies in Oman and potentially other regions.
• Understanding this new virus is vital for protecting squash cultivation and related cucurbit crops.