Parthenocarpy is a desired trait in tomato since it can overcome problems with fruit setting under unfavorable conditions. A parthenocarpic tomato cultivar, â??MPK-1', with a parthenocarpic gene, Pat-k, exhibits stable parthenocarpy, thus, producing few seeds and are propagated inefficiently via cuttings. The team of Rihito Takisawa from Kyoto University in Japan isolated the Pat-k gene to study its relationship with parthenocarpy and low seed set.
Results showed that Pat-k is located in the 529 kb interval between two markers, where 60 genes exist. The team also found that the SlAGAMOUS-LIKE 6 (SlAGL6) gene of â??MPK-1' was mutated. This resulted in lowered transcript levels of SlAGL6 in ovaries of â??MPK-1' than a non-parthenocarpic cultivar.
From these results, the team concluded that Pat-k is SlAGL6, and its downregulation in â??MPK-1' causes parthenocarpy and low seed set. Moreover, down-regulation of Pat-k/SlAGL6 could cause abnormal ovule formation, leading to a reduction in the number of seeds.