Expression analysis and association of bulbing to FLOWERING LOCUS T (FT) gene in short day onion (Allium cepa L.)

Abstract

The present study was carried out with the objective of studying the expression of FLOWERING LOCUS T (FT) genes responsible for bulbing in onion. Six AcFT genes were used for expression studies at prebulbing (45 DAT), bulbing (60 DAT) and post bulbing (75 DAT) stage. Two varieties viz., Brown Spanish (long day) and Pusa Riddhi (short day) were used. It was observed that out of the reported six AcFT primers, four were able to amplify. Two new primers exhibiting amplification of AcFT1 and AcFT6 are reported. In short day onion variety, Pusa Riddhi, expression of five out of six genes studied (AcFT1, AcFT3, AcFT4, AcFT5 and AcFT6) were highest at the bulbing stage (60 DAT) suggesting their role in bulbing. In long day variety, Brown Spanish, expression of all the six genes except AcFT1 was very low at bulbing stage (60 DAT). This signifies that specific photoperiod conditions for gene expression were not achieved under Delhi conditions in long day onion. More studies towards understanding of the genes need to be addressed to understand the basic molecular process of bulbing in short day onion.