XVEpro:ABI3 line 3 (fus3-T as background)

ABA-INSENSITIVE 3 (ABI3) has long been known for activation of storage protein accumulation and it has regulatory interaction with FUSCA3 (FUS3), an activator of oil accumulation. However, the role of ABI3 in oil accumulation and its interaction with FUS3 remain unclear. Expressing ABI3 in rosette leaves of fus3 knock-out mutant still caused up to three-fold greater triacylglycerol accumulation, indicating ABI3 can activate lipid accumulation independently of FUS3. Transcriptome analysis revealed that lipid droplet protein (LDP) genes including OLEOSINs and CALEOSINs were highly up-regulated up to 1000 times by ABI3 in the absence of FUS3, while the expression of WRI1 was doubled. ABI3 activates oil accumulation with or without FUS3, most likely through up-regulating LDPs and WRI1.