CONSTANS acts in the phloem to regulate a systemic signal that induces photoperiodic flowering ofArabidopsis

PSEUDO RESPONSE REGULATORs stabilize CONSTANS protein to promote flowering in response to day length

“…To further analyze the role of PRRs in FT transcription, the effects of prr mutations on FT expression were tested in a transgenic line expressing CO from the SUC2 promoter (An et al , 2004), thereby uncoupling CO transcription from impaired clock function in prr mutants. The SUC2 promoter expresses CO specifically in the phloem companion cells where it acts in WT plants to promote FT transcription (An et al , 2004).…”

“…The SUC2 promoter expresses CO specifically in the phloem companion cells where it acts in WT plants to promote FT transcription (An et al , 2004). In these plants, FT expression was highly induced compared with WT due to increased accumulation of CO mRNA specifically in the phloem cells (Fig 2A and B).…”

“…SUC2 :: CO and SUC2 :: HA:CO have been previously described (An et al , 2004; Jang et al , 2009). All of the single, double, triple, and quadruple prr mutants with SUC2 :: CO and SUC2 :: HA:CO were generated by genetic crossing.…”

Long-distance movement of ArabidopsisFLOWERING LOCUS TRNA participates in systemic floral regulation

“…The DNase I-treated Arabidopsis total RNA was used for reverse transcription with Superscript III reverse transcriptase (Invitrogen), and oligo (dT) [12][13][14][15][16][17][18] according to the manufacturer's instructions. The cDNA equivalent to 20 ng of RNA was used for PCR reactions with the Power SYBR Green PCR master mix (Applied Biosystems).…”

J3 regulation of flowering time is mainly contributed by its activity in leaves

“…To examine the effect of spatial expression of J3 on regulating flowering, we created two constructs in which J3 coding sequence was driven by either the promoter of SUCROSE TRANSPORTER 2 (SUC2), which is active specifically in phloem companion cells, 20 or the KNAT1 promoter, which is active in SAMs. 21 The resulting constructs, pSUC2:J3 and pKNAT1:J3, were transformed into j3-1 loss-of-function mutants to test whether they could rescue the late-flowering phenotype of j3-1 mutants. Over twenty transgenic plants were generated for each construct and the flowering time of each independent line was scored at the T1 generation.…”