Phenotypic performance of transgenic potato (Solanum tuberosum L.) plants with pyramided rice cystatin genes (OCI and OCII)

Abstract

The evaluation of transgenic plants which is usually carried out under controlled conditions in culture rooms and greenhouses can yield valuable information about the influence of introduced genes on a transgenic plant phenotype. However, an overall assessment of plant performance can only be made by testing transgenic plants in the field environment. Thus, the effects of pyramided rice cystatin genes OCI and OCII on morphological parameters of transgenic potato cv. Desiree, Dragacevka and Jelica lines were compared under in vitro, greenhouse, and field conditions. All analyzed OC co-expressing transgenic lines exhibited normal phenotype, both in vitro and in greenhouse conditions. In the field environment, eight of nine OCI/OCII lines were similar to the wild-type control plants in their general phenotypic appearance. Yield parameters, such as tuber number and tuber weight for these phenotypically normal OCI/OCII lines, were also comparable to the controls. Only transgenic cv. Jelica line 4 plants exhibited slightly reduced growth, atypical leaf morphology and, contrary to the plants of other transgenic lines and untransformed controls, failed to flower. However, despite the phenotypic and developmental changes under field conditions, the OCI/OCII Jelica line 4 did not exhibit a significant decrease in tuber yield. Stacking of OCI and OCII genes preserves important attributes of the parental lines, confirming that this approach could be suitable for improving agronomical traits in potato.