Polygalacturonase genes in tomato flower and leaf abscission zones- A novel trait for molecular breeding

Abstract: Abscission of plant organs is a key process during plant life cycle and prerequisite factor involved in limiting the spread of disease, shedding of un-pollinated flowers and facilitates dispersal of seeds. In agricultural context, abscission may become a major limiting factor for crop productivity. The organs abscise at a specific position called abscission zone (AZ) and it is one of the prime traits to be manipulated during the crop improvement process towards the selection of reduced abscission lines. The tomato abscission polygalacturonase (TAPG) genes are abscission induced polygalacturonases and specifically induced in the AZ, which plays a major role in AZ separation. The current study had accentuated to identify the entire polygalacturonase gene families in tomato AZs, through AZ specific customized microarray. The results revealed that TAPG1, 2, 5, 7 and TPG6, PS2 genes were specifically induced and continuously over-expressed linearly along with abscission progression in tomato flower AZ. Similarly, the same set of genes were up-regulated upon abscission induction at the early hours (24 h) in the leaf AZ, indicating potential involvement in organ abscission. Our study provides new insights for the regulation of the early events in the process of tomato organ abscission and a novel trait for molecular breeding.