FIGURE 5.

Plant assays of RR gene mutants and other Xoc strains. For pathogenicity assays, Rice (Oryza sativa L. ssp. japonica) cv. Nipponbare was used as host plant. The bacterial suspensions concentration of each Xoc strain was adjusted to OD₆₀₀ = 0.5 by the sterilized deionized water. Bacterial suspensions were infiltrated into the rice leaves (6 weeks), on the back of the main vein side, by using needleless syringe. Wild-type strain and sterilized deionized water were used as controls. For hypersensitive response (HR) elicitation test, tobacco (N. benthamiana) was used as non-host plant. Significance was tested by Student’s T-test (^∗ and ^∗∗ indicate significances at P < 0.05 and 0.01, respectively). (A) Leaf streak disease symptoms caused by Xoo strains on inoculated leaves of rice. CNK2201 indicates the complement strain of GX_XOC2201 mutant. (B) The length of disease lesions was measured at 14 days after infiltration inoculation of RR mutants. The results were the average of 20 infiltration spots. The letters in circles beneath the horizontal axis indicate the HR intensities elicited by Xoc strains: H, normal HR; W, weak HR; Z, no HR.