Effect of the level of “Candidatus Liberibacter solanacearum” infection on the development of zebra chip disease in different potato genotypes at harvest and post storage

Abstract

Potato psyllid (Bactericera cockerelli Sulc)-transmitted "Candidatus Liberibacter solanacearum" (Lso) has been negatively impacting the potato industry in the United States as well as other potato-producing countries. Lso has been linked to a condition known as zebra chip (ZC) that affects yield and quality of potato tubers. Efforts to find sources of resistance to ZC have primarily focused on greenhouse evaluations based on a single inoculation time prior to harvest. Plant response to infection, however, could be influenced by the developmental stage of the host plant, and ZC may continue to develop after harvest. The objectives of this study were to quantify Lso inoculation success, Lso titer, ZC severity and Lso development during storage in eight potato genotypes. These evaluations were conducted on plants infested with Lso-positive psyllids at 77, 12, and 4 days before vine removal (DBVR). The evaluated genotypes were categorized according to their relative resistance to Lso and tolerance to ZC symptoms. Lso inoculation success in the genotype family A07781, derived from Solanum chacoense, was lower than that of the susceptible control ('Russet Burbank'). A07781-4LB and A07781-3LB genotypes were characterized relatively resistant to the pathogen and highly tolerant to ZC symptoms, while A07781-10LB was categorized as susceptible to Lso but relatively tolerant to symptom expression. In stored potatoes, increase in Lso concentrations was observed for all infestation times. However, significantly higher Lso titer was detected in tubers infested 12 DBVR and the effect was similar across genotypes. Overall, the A07781 family can be considered as a promising source of resistance or tolerance to ZC.

SÍNTOMAS FOLIARES, BIOMASA Y CALIDAD DE TUBÉRCULO DE GENOTIPOS DE PAPA INOCULADOS CON Candidatus Liberibacter solanacearum

“…Rashidi et al (2017) observaron tolerancia relativa de algunos genotipos, comparados con Russet Burbank, porque encontraron variación significativa en la severidad de los síntomas de tubérculos sin freír y también después del freído. También, Cruzado et al (2020) encontraron varios genotipos con baja susceptibilidad a CaLso y síntomas leves de zebra chip, aunque el tiempo de infección (etapa de desarrollo) tiene efecto en el grado de resistencia. Algunos genotipos, como Russet Burbank, muestran baja susceptibilidad a CaLso, pero son altamente intolerantes a la infección, debido a la alta expresión de los síntomas.…”

A comprehensive review of zebra chip disease in potato and its management through breeding for resistance/tolerance to ‘Candidatus Liberibacter solanacearum’ and its insect vector

“…Six breeding clones, previously identified as resistant to ZC and/or potato psyllid, 170,174,175 and two varieties were evaluated for CLso transmission, titer, and development of ZC symptoms. 181 No significant differences were observed in CLso transmission among entries in the greenhouse, but differences in CLso titer and ZC tuber symptoms were observed among entries in the caged field evaluations following infestation with CLso-positive potato psyllids. Full-sibling breeding clones A07781-3LB and A07781-4LB were categorized as relatively resistant to CLso with lower titers and reduced raw tuber ZC symptoms following harvest and extended storage relative to other clones and varieties.…”

“…Six breeding clones, previously identified as resistant to ZC and/or potato psyllid, 170,174,175 and two varieties were evaluated for CLso transmission, titer, and development of ZC symptoms 181 . No significant differences were observed in CLso transmission among entries in the greenhouse, but differences in CLso titer and ZC tuber symptoms were observed among entries in the caged field evaluations following infestation with CLso‐positive potato psyllids.…”

Biology, Ecology, and Management of the Potato Psyllid, Bactericera cockerelli (Hemiptera: Triozidae), and Zebra Chip Disease in Potato

“…Resistance to Lso or the potato psyllid vector has yet to be identified in or developed for commercial potato cultivars in the United States (29,66,79). However, potential sources of resistance have been found in several germplasms with wild Solanum species in their pedigree (94).…”

“…Recent studies have used symptom severity, Lso titer (29,103), and/or analytical quantification of physiological responses (109,138,139) to determine potato host susceptibility to ZC. Wallis et al (138) identified 29 genotypes that expressed few or no symptoms following Lso infection.…”