Closely-related Xanthomonas citri pv. citri isolates trigger distinct histological and transcriptional responses in Citrus limon

ORCE, IG; DEBES, M; SENDÍN, LN; LUQUE, AC; ARIAS, ME; VOJNOV, AA; MARANO, MR; CASTAGNARO, AP; FILIPPONE, MP

SCIENTIA AGRICOLA

UNIV SAO PAOLO

Lugar: Piracicaba; Año: 2016

0103-9016

Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), has an important economic impact on citrus industry. Extensive information is available about disease, nevertheless the study of plant-pathogen interactions could provide new information in the understanding of citrus canker disease., but genetic bases promoting the disease are still unclear. A new isolate has been identified, Xcc AT, which has a high genetic similarity (>90%) to virulent Xcc T reference strain based on genetic clustering analyses of the rep-PCR fingerprinting patterns, but it does not produce cankerous lesions in a host-specific interaction with Citrus limon. In this study, we compared C. limon responses to Xcc AT and to the virulent Xcc reference T strain at both histological and transcriptional levels. Histologically, leaves inoculated with Xcc AT did not exhibited neither a typical disordering of the spongy mesophyll, nor a swelling of epidermisal. A particular content (undetermined) was also found in mesophyll cells near stomata, together with an increased starch accumulation. The transcriptomic profiles were compared by using cDNA-AFLP technique. A total of 121 fragments derived from transcript (TDF) were either specifically induced or repressed by the isolates, and 62 were sequenced. Analysis of global expression identified different classes of genes known to be involved in plant?pathogen interactions. This work constitutes the first approach in the study of the specific interaction between the avirulent Xcc AT isolate and C. limon.