Major Viruses Infecting Welsh Onion (Allium fistulosum) in West Java, Indonesia

Abstract

Welsh onion (Allium fistulosum) is an important vegetable crop in the highlands of West Java. Information on the viruses infecting this crop remains limited. This study aimed to determine disease incidence, detect target viruses, and identify potential insect vectors at five locations in West Java. Virus detection from symptomatic leaves was conducted by one-step reverse transcription polymerase chain reaction (RT-PCR) using specific primers for onion yellow dwarf virus (OYDV), leek yellow stripe virus (LYSV), shallot yellow stripe virus (SYSV), shallot latent virus (SLV), and garlic common latent virus (GCLV), while universal primers were used for Orthotospovirus. Potential vectors were identified using morphological characters and cytochrome c oxidase subunit I (COI) gene analysis. The highest incidence of symptomatic plants occurred in Pamijahan, Bogor (97.83%), and the lowest was found in Pacet, Cianjur (9.67%). SLV was detected most frequently (97.87%), followed by OYDV (34.04%) and SYSV (10.64%). Iris yellow spot virus (IYSV) was confirmed in two of seven samples with necrotic spots, whereas LYSV and GCLV were not detected. Neotoxoptera formosana and Thrips sp. may serve as vectors based on positive detections of SLV and IYSV, respectively. These findings contributed important knowledge regarding viruses infecting Welsh onion in Indonesia.

Bawang daun (Allium fistulosum) merupakan salah satu komoditas sayuran penting di dataran tinggi Jawa Barat. Informasi mengenai virus yang menginfeksi tanaman ini masih terbatas. Penelitian ini bertujuan menentukan insidensi penyakit, mendeteksi virus sasaran, dan mengidentifikasi serangga vektor potensial di lima lokasi di Jawa Barat. Deteksi virus dari sampel daun bergejala dilakukan menggunakan one-step reverse transcription polymerase chain reaction (RT-PCR) dengan primer spesifik untuk onion yellow dwarf virus (OYDV), leek yellow stripe virus (LYSV), shallot yellow stripe virus (SYSV), shallot latent virus (SLV), dan garlic common latent virus (GCLV), serta primer universal untuk Orthotospovirus. Serangga vektor potensial diidentifikasi berdasarkan karakter morfologi dan analisis gen cytochrome c oxidase subunit I (COI). Insidensi tanaman bergejala tertinggi ditemukan di Pamijahan, Bogor (97,83%), sedangkan yang terendah ditemukan di Pacet, Cianjur (9,67%). SLV paling sering terdeteksi (97,87%), diikuti oleh OYDV (34,04%) dan SYSV (10,64%). Iris yellow spot virus (IYSV) dikonfirmasi pada dua dari tujuh sampel bergejala bercak nekrotik, sedangkan LYSV dan GCLV tidak terdeteksi. Neotoxoptera formosana dan Thrips sp. berpotensi sebagai vektor berdasarkan terdeteksinya SLV dan IYSV pada masing-masing serangga tersebut. Temuan ini memberikan informasi penting mengenai virus yang menginfeksi bawang daun di Indonesia.