Entomologists from the University of California Riverside, together with researchers from INIFAP (Mexico), characterised four promising potato lines (246, 865, 510, NAU) exposed to Cls-positive adult psyllids and monitored the vector's behaviour towards the plants and the effects of the bacteria on the tubers. The potato lines were compared to ZC-susceptible variety Atlantic.
ZC symptoms 2 months after harvesting. From no symptoms (level 0) to compromised tuber (level 3).
Results showed that the psyllid preferred to settle on Atlantic, 246 and 865 and oviposit on Atlantic compared to 510. However, tolerance to ZC appeared more dependent on the host's responses to Cls infection. All four genotypes exhibited putative ZC tolerance in raw tubers compared to the susceptible commercial variety, Atlantic. Expressed tolerance was associated with reduced concentrations of phenolic compounds in Cls-infected raw tubers compared to Altlantic tubers. Lower phenol concentrations corresponded to a reduction of symptoms in freshly-cut tubers. However, the four genotypes showed ZC-related colouring in fried potatoes due to an increase of the sugar content, typical of Cls infection. This means that, despite their being tolerant to ZC, they are not suitable for the chip industry.
"Considering that, in Mexico, the production of potatoes for the fresh market is almost 60% against the 30% of industry potatoes, these four lines might be useful for the former. Without forgetting that they might be used in genetic improvement programmes to develop new more tolerant and/or resistant varieties."
Source: Rubio-Covarrubias O. A., Cadena-Hinojosa M. A., Prager S. M., Wallis C. M., Trumble J. T., 'Characterization of the Tolerance against Zebra Chip Disease in Tubers of Advanced Potato Lines from Mexico', 2017, American Journal of Potato Research, DOI 10.1007/s12230-017-9570-8.