The transgenic T1 populations were screened on MS agar media containing 25 mg l-1 Hygromycin and 25 mg l-1 Basta. To generate GFP-PPKs lines, the coding sequences of PPKs were PCR-amplified and cloned into a Ti plasmid (pFGFP) modified from pCambia3301 by the In-Fusion cloning method, resulting in expression of GFP-PPKs driven by the ACTIN2 promoter (pACT2::GFP-PPKs). Ti plasmids expressing recombinant proteins were introduced into rdr6-11 allele, which suppresses gene silencing, by the floral-dip method51. The transgenic T1 populations were screened on compound soil sub-irrigated with the Basta solution. Plants were grown in walk-in growth chambers at 22 °C, 65% relative humidity under cool white fluorescent tubes. Long-day (LD) photoperiod is defined as 16 h light/8 h dark. Light-emitting diode was used to obtain monochromatic blue light (peak 450 nm; half-bandwidth of 20 nm), red light (peak 660 nm; half-bandwidth of 20 nm) or far-red light (peak 730 nm; half-bandwidth of 20 nm).