Molecular detection of Xanthomonas oryzae pv. oryzae from West Java and its in vivo pathogenicity test

Abstract

Bacterial Leaf Blight (BLB) is a severe disease that reduces rice crop yields. It is caused by Xanthomonas oryzae pv oryzae (Xoo). The BLB disease can be manage through some ways, such as the adoption of BLB resistant varieties. It is necessary to investigate this disease because of the BLB outbreak cases in several regions in Indonesia, especially in West Java as the center of rice production. This study aimed to identify the Xoo from ten districts in West Java by applying diagnostic molecular markers for Xoo (XO, Xoo4009, and Xoo2976) using colony PCR and assess the virulence level of in vivo pathogenicity test using resistant varieties (IRBB7 and Conde) and susceptible varieties (IR64 and TN 1). The bacterial isolation resulted 50 isolates and detected four positive Xoo isolates i.e. Xoo-6 (Cicalengka, Bandung), Xoo-17 (Sindang Karya, Karawang), Xoo-19 (Rawamerta, Karawang), and Xoo-21 (Teluk Jambe, Karawang) and showed 98% similarities. The highest level of virulence of isolates was found in Xoo-6 and the lowest level was found in Xoo-21 isolates. The BLB disease intensity in the vegetative phased plants was higher than generative phased.