Abstract
Root-knot and cyst nematodes cause serious losses to potato production in the United States. Globodera pallida, which was found in Southern Idaho in 2006, has led to thousands of acres of prime potato production land being quarantined. Solanum sisymbriifolium is an undomesticated relative of potato that is resistant to the major nematode threats in potato. To determine if S. sisymbriifolium genes differentially expressed in the presence of G. pallida have nematode-induced regulatory regions, Cis-regulatory regions from six genes were identified within a bacterial artificial chromosome library containing the S. sisymbriifolium genome. Later, two cis-regulatory regions were identified within the published S. sisymbriifolium genome. Roughly 500 and 3000 base fragments of each region were amplified, then transformed into the β-glucuronidase-containing binary vector pCAMBIA 1391z. Stable transformants and transient experiments in Nicotiana benthamiana were used to determine gene expression levels of the cis-regulatory regions in roots and leaves in uninduced conditions, in the presence of the nematode-associated molecule ascaroside #18, and in the presence of Meloidogyne hapla second-stage juveniles. A 691-base fragment of a cell-wall-associated kinase cis-regulatory region was shown to have significantly similar functionality to a constitutive promoter, while the five full-length cis-regulatory regions showed significantly higher gene expression than a constitutive promoter in both mock and ascaroside #18 treatments. Regulatory element analysis with PlantPAN revealed root-associated elements peaked within 1000 bases upstream of the TATA box. Identifying nematode-induced cis-regulatory regions with strong functionality in roots is a big step towards bringing potatoes back to quarantined and infested fields.