Functional analysis of a class I patatin gene SK24-1 in microtuber formation of transgenic potatoes

Expression of a class I patatin cDNA clone, SK24-1, in Escherichia coli revealed that the cDNA clone possessed lipid acyl hydrolase (LAH) activity. Transformed potato plants were obtained via Agrobacterium-mediated transformation using the chimeric constructs containing the sense and antisense cDNA under the control cauliflower mosaic virus 35S (CaMV 35S) promoter. In some sense transformed plants, both sense patatin RNA and LAH activity were increased and further resulted in a significant increase of percentage of plantlets that formed microtubers and numbers of microtubers per plantlet in vitro. All antisense plants displayed a reduction in LAH activity. Both sense and antisense RNA could be detected in antisense plants, but transcripts of antisense RNA resulted in a reduction of endogenous sense RNA. Moreover, expression of antisense cDNA in some antisense transformed plants led to a significant decrease in the number of microtubers formed. These results suggest that SK24-1 was involved in regulating microtuber formation. Key words: Patatin, potato, Escherichia coli, sense RNA, antisense RNA

Transformation of potato using an antisense class I patatin gene and its effect on microtuber formation

An antisense class I patatin gene under control of the CaMV 35S promoter was introduced into potato (Solanum tuberosum) cultivar E-potato 3 using the Agrobacterium tumefaciens system. PCR amplification and PCR–Southern blot analysis indicated that the antisense class I patatin gene had been integrated into the potato genome. Northern hybridization analysis showed that the antisense gene transcribed normally in the transgenic potato plants and resulted in a reduction of endogenous class I patatin mRNA. Total soluble protein content and lipid acyl hydrolase activity of microtubers, derived from transformed plants, decreased by a maximum of 36.4% and 31.4%, respectively, compared with control plants. The expression of this antisense gene also resulted in reductions of the plantlets forming tubers, tubers per plantlet and the effective tubers (≥50 mg) of the transformed plants.