Characterization of host plant resistance to zebra chip disease from species-derived potato genotypes and the identification of new sources of zebra chip resistance

PLoS One. 2017 Aug 23;12(8):e0183283. doi: 10.1371/journal.pone.0183283. eCollection 2017.

Abstract

'Candidatus Liberibacter solanacearum' (Lso), an uncultivable phloem-limited phytopathogenic bacteria, is known to be associated with Zebra Chip disease (ZC), which represents a major threat to potato production in the US and elsewhere. This pathogen is transmitted by the phloem-feeding potato psyllid, Bactericera cockerelli Sulc (Hem. Triozidae). Currently, there are no reports of resistance to ZC in cultivated potatoes. This greenhouse study was conducted to evaluate Lso transmission success and the susceptibility of 11 potato breeding clones, representing diverge genetic background, to ZC, in relation to a susceptible commercial cultivar, Russet Burbank. Individual plants were exposed to two Lso-positive potato psyllids for 48 hours. The percentage of successful Lso transmission varied across the evaluated genotypes ranging between 7 and 57%. Freshly-cut and fried tubers showed significant variation in ZC symptom severity among the breeding clones, with several genotypes expressing relative tolerance when compared to Russet Burbank. None of the evaluated clones showed statistically lower Lso titers than Russet Burbank with the exception of one genotype in the second year of the study. However, the presence of a non-significant relationship between average symptom severity and Lso titer indicated variations in phenotypic responses (i.e. tolerance) to Lso existed among evaluated breeding lines. Breeding clones A07781-3LB, A07781-4LB and A07781-10LB had relatively lower Lso titer (low susceptibility) and tuber symptom expression (high tolerance) among the tested genotypes. As these three clones represent full siblings, the observed effects could be indicative of the presence of a genetic basis for resistance/tolerance to ZC. Findings provide a better understanding of resistance/tolerance to ZC, and contribute to continued efforts in breeding for resistance to this disease.

MeSH terms

  • Bacterial Infections / immunology
  • Bacterial Infections / microbiology*
  • Genes, Plant*
  • Genotype
  • Plant Diseases / immunology
  • Plant Diseases / microbiology*
  • Solanum tuberosum / genetics
  • Solanum tuberosum / immunology
  • Solanum tuberosum / microbiology*

Grants and funding

This work was supported by the United States Department of Agriculture- National Institute of Food and Agriculture (2014-67014-22408); United States Department of Agriculture- National Institute of Food and Agriculture, Hatch project IDA01506 to AR; United States Department of Agriculture-ARS-State Partnership Potato Grant (Agreement #58-5366-4-008) to RGN and AR.