The species and distribution of viruses in the garlic germplasm resources of China

Abstract:

Virus infection leads to severe yield reduction and quality deterioration in garlic production. It is of great significance to collect, monitor, and conserve garlic germplasm resources for genetic improvement of garlic yield, virus resistance, and quality. [Objective] To reveal the virus-carrying status and distribution of garlic resources in China. [Methods] We employed two multiplex reverse transcription-polymerase chain reaction(RT-PCR) methods to evaluate the distribution of seven virus species among 689 garlic germplasm accessions. [Results]Allexivirus[GarV-A, GarV-B, GarV-C, GarV-D, GarV-E, GarV-X, and shallot virus X (ShVX)] had the highest detection rate (98.69%), followed by onion yellow dwarf virus (OYDV, 90.13%), garlic mite-borne filamentous virus (GMBFV, 71.12%), leek yellow stripe virus (LYSV, 50.65%), shallot latent virus (SLV, 49.20%), potato Y virus (PVY, 41.94%), and garlic common latent virus (GarCLV, 32.08%). Among these garlic accessions, 27 (3.92%), 122 (17.71%), 190 (27.58%), 150 (21.77%), 129 (18.72%), 62 (9.00%), and seven (1.02%) accessions carried seven, six, five, four, three, two, and one virus species, respectively, while two (0.29%) accessions did not carry any virus. In addition, there was a significantly positive correlation between the planting generations of garlic resources and the number of virus species (P<0.05). Shoot tip culture can effectively reduce or eliminate viruses. [Conclusion] This study reveals the distribution of seven main virus species in garlic germplasm resources in China, providing a theoretical basis for the safe preservation of garlic germplasm resources and enriching the gene resources for the breeding of antiviral garlic germplasm.

Key words:garlic;germplasm resources;virus;multiplex RT-PCR;shoot tip virus-free culture