Fig. 3. Candidatus Liberibacter asiaticus (CLas) induces ROS production and cell death in phloem tissue of C. sinensis.

a Trypan-blue staining assay to detect cell death in leaves of CLas-infected C. sinensis “Valencia” trees. b Determination of H₂O₂ concentration in CLas negative or positive leaves showing different symptoms. Mean and SD (n = 3) are shown. c, d H₂O₂ (c) and ion leakage (d) assays of exudates extracted from phloem-enriched bark tissues. Data are presented as mean values ± SD (n = 4). Statistical differences were analyzed using two-tailed Student’s t test. ND non-detected. For (a, b): AS asymptomatic. MS Mildly symptomatic. SS Severely symptomatic. AS, MS, and SS were collected from HLB-positive trees. For (c, d), Healthy stems of spring sprouts were collected from healthy branches of CLas-negative plants. Symptomatic stems of spring sprouts were collected from branches with HLB symptomatic leaves of CLas-positive plants. Each experiment contains three to four biological replicates. The experiments were repeated at least twice with similar results. CLas titers were determined by qPCR as shown by Ct values with lower Ct values indicating higher bacterial titers. Source data are provided as a Source Data File.