Surface barriers of mandarin cv. 'Okitsu' leaves make a major contribution to canker disease resistance

FAVARO MA, ; MICHELOUD NG, ; ROESCHLIN RA, ; CHIESA MA,; CASTAGNARO AP, ; VOJNOV AA, ; GMITTER F, ; GADEA VACAS J, ; RISTA LM, ; GARIGLIO NF, ; MARANO MR

PHYTOPATHOLOGY

AMER PHYTOPATHOLOGICAL SOC

Año: 2014

0031-949X

Field evaluations have shown that Satsuma mandarin (Citrus unshiu)?Okitsu? is one of the mandarin cultivars that shows substantial resistanceto Xanthomonas citri subsp. citri (X. citri), the causal agent of citrusbacterial canker disease. However, the mechanisms underlying thisresistance are not well understood. In this study, we have shown that?Okitsu? leaves are nevertheless susceptible to X. citri infection during aperiod of their development; however, this period is shorter than that seenin the susceptible mandarin ?Clemenules? (C. clementina). Under controlledgrowth conditions, the resistance of ?Okitsu? to X. citri wasassociated with the age of the leaf and was evident in spray-inoculatedplants but not in those inoculated by infiltration. Furthermore, X. citrishowed reduced attachment and biofilm formation in ?Okitsu? leavescompared with ?Clemenules?. Taken together, our data suggest thatstructural features of the ?Okitsu? leaf surface, such as the physicalproperties of the cuticle, are involved in the resistance to X. citri.