Introduction of A Nonhost Gene Rxo1 Cloned from Maize Resistant to Rice Bacterial Leaf Streak into Rice Varieties

Bacterial leaf streak (BLS) of rice, caused by Xanthomonas oryzae pv. oryzicola (Xooc), is a destructive bacterial disease in China. Single-gene resistance to Xooc has not been found in rice germplasm. A cloned nonhost gene from maize with resistance to BLS, Rxo1, was transferred into four Chinese rice varieties through an Agrobacterium-mediated transformation system, including Zhonghua 11, 9804, C418, and Minghui 86. Polymerase chain reaction (PCR) and Southern blot analysis of the transgenic plants showed the integration of the Rxo1 gene into the rice genomes. The integrated Rxo1 gene was stably inherited, and segregated in a 3:1 (resistance: susceptible) ratio in the selfed T1 generations derived from some T0 plants, indicating that the Rxo1 gene is inherited as a dominate gene in rice. Transgenic T0 plants and PCR-positive T1 plants were resistant to Xooc on the basis of artificial inoculation