Table. S1 Primer sequences used for the in situ hybridization,real-time PCR,and semi-quantitative PCR.

Gene / Sequence (5'-3')
PtSVP / Real-time PCR / Sense GACAGCAAGTGGCGGAGGTAT
Anti GTAAGCCCAGCTTGAGGGAGG
PtSVP / in situ hybridization / SenseCTCAAGAAGCATGAAGGAAA
Anti TCTATCACTCGTCCCAATCC
PtSVP / Semi-quantitative
PCR / Sense GTAACAGCTAGCAAGCAAGCG
Anti TTAGTTGATGAAGCGAAGACCG
CiFT / Semi-quantitative
PCR / Sense ATCCTCTTATTGTTGGCCGCGTTG
Anti TGGTGCGTAAACAGTCTGCCTCCC
CiFT / Real-time PCR / Sense TGATAGTCCAGCAACCACAG
Anti GGAGGTCCCAGATTGTAAAG
CsWUS / Semi-quantitativePCR / Sense CTGGTGGTCAAATGGGAGA
Anti GGGTTTCAATACCTGGGTG
CsWUS / Real-time PCR / Sense GGCATAGACCCACACACTTCATC
Anti GGAGGGTTTCAATACCTGGGTG
ACTIN / Real-timeand semi-quantitative PCR / Sense CCGACCGTATGAGCAAGGAAA
Anti TTCCTGTGGACAATGGATGGA

Fig. S1. The flowering abilities of spring and summer shoot of the precocious and the wild-type trifoliate oranges.(a, b): precocious trifoliate orange; (c, d): wild-type trifoliate orange. (a, c) the spring shoots; (b, d) the summer shoots.The spring shoot of both trifoliate orange are flowering-competent; the summer shoot of the precocious is able to flower but the summer shoot of the wild-type is not.

Fig. S2. The vertical sections of developing lateral buds on spring shoot. (a) is a lateral bud inundetermined state. (b to h) show the successive developmental stages of flower bud from stage 1 to 7. (b) The stage 1: lateral buds begin transitionto be a floral meristem, and the sepal primordia initiated. (c) The stage 2: petal primordia arise and sepals overlie flower meristem. (d) The stage 3: stamen primordia arise. (e)the stage 4:pistilprimordia arise. (f) The stage 5: pistilprimordium parcelsthe apical meristemupwards from the edge. (g) The stage 6: Pistil form a closed structure and sporogenous cell form in stamen. (h) The stage 7: flower bud became structural integrity and the ovuleprimordia appear in ovary. AM, apical meristem of lateral bud;B, bract; CP, carpel primordia; FAM, floral apical meristem; OP, ovuleprimordia; P, petal; Pi, pistil; PiP, pistilprimordia; PP, petalprimordia; S, sepal; SP, sepalprimordia; St, stamen; StP, stamenprimordial. Bar=50µm

Fig. S3. Identification partial lines of 35S::PtSVP transgenic tobaccos. M, maker; P, 35S::PtSVP plasmid as a positive control; WT, wild type tobacco as a negative control; L1, L3, L4, L5, L7, L8, L21, L25, L26, L28, L30, L31, L33, L39, L42, L43, L44, L47, L48, L50, L53 and L60 are the 35S::PtSVP transgenic tobacco lines.

Fig. S4.The early developmentphenotypes of different lines of tobaccos and the expression level of PtSVP in them.(a) Wild-type tobacco. (b) Line 10 is a false positive tobacco. Three lines of positive 35S::PtSVPtransformants were selected randomly for further study,they are (c, d ande)respectively L8, L26and L31. (a, b, c, d and e) are in the similar developmental stage.Co, Coflorescence; TF, Top flower. (f) A semi-quantitative PCR was performed to measure the expression of PtSVP in the selected lines. Lane P was a positive control using 35S::PtSVP plasmid as template,and WT is wild-type tobacco used as a negative control. L10 was a false positive tobacco; L8, L26and L31 wererespectively the lines shown in (c, d ande).

Fig. S5. Theflowerphenotypes of wild-type and 35S::PtSVP transgenic tobaccos. Compared to the wild-type tobacco (at the left side of a, b and c), there were some abnormal coflorescences and flowers in 35S::PtSVP transgenic tobacco (at the right side of a,b, and c).

Fig. S6. The expression of PtSVP in different tissues. PtSVP was widely expressed in root (a), leaf (b), stem (c), the whole ovary (d, e and f) and seed (g). PtSVP was expressed especially strongly in meristems like root meristem (RM) and embryo (Em) in ovule (Ov). Bar=50µm

Fig. S7 The conservation analysis between PtAP1 and CsAP1. (a) The base sequence alignment shows high homology between PtAP1 and CsAP1. (b) The amino acid sequencealignment between PtAP1 and CsAP1 proteins also indicated high conservation.