1. Suppl. Fig. S1 Suppl. Fig. S1 The nucleotide sequence and its deduced amino acid sequences of CaSAMDC. The full-length of CaSAMDC (GenBank Accession No. JX875948) was 1,681 bp in length and consisted of a 523-bp 5’-UTR, a 1,095-bp coding region of 364 amino acids, and a 63-bp 3’-UTR. CaSAMDC contained overlapping two uORFs consisting of two and 50 amino acids that overlap by one base in the 5’-UTR

2. Suppl. Fig. S2 a b

3. Suppl. Fig. S2 Sequence analysis of hot pepper CaSAMDC. a Multiple alignments of 10 plant SAMDC genes. The predicted amino acid sequence of CaSAMDC (GenBank Accession No. JX875948) was compared with those of proteins from carnation (CSAMDC1, U38526; CSAMDC2, U38527), Arabidopsis (ASAMDC1, U63633; ASAMDC2, AJ251915), morning glory (InSAMDC, AAC04611), tobacco (NtSAMDC, U91924), soybean (GmSAMDC, AF488307), cottonwood (PtSAMDC, EEF07896) and tomato (SiSAMDC, ABY55855). Amino acid sequences conserved in all ten proteins are indicated in black. b Phylogenetic relationship of the ten SAMDCs from various plant species

4. NPTII 35S CaSAMDC RBLB NOS-pro NOS-ter BamHIHindIII pBI121 1 43795016815241618 ATGTAA 1544 227379 150 HindIII Suppl. Fig. S3 Suppl. Fig. S3 A Schematic representation of the CaSAMDC-overexpressing gene construct in the pBI121 vector. LB, left border; NOS-Ter, terminator sequence from nopaline synthase gene; 35S, CaMV 35S promoter; NPT II, neomycin phosphotransferase; NOS-Pro, promoter sequence from nopaline synthase gene; RB, right border

5. 10.0 3.0 8.0 5.0 4.0 3.5 2.5 Kb Col-0#2#4Col-0#2#4 SacIScaI Suppl. Fig. S4 Suppl. Fig. S4 Genomic Southern blot analysis of WT and 35S::CaSAMDC transgenic Arabidopsis lines #2 and #4. Genomic DNA (10 μg per lane) from Arabidopsis seedlings was digested with ScaI and SacI enzymes, blotted onto nylon membranes, and hybridized with the [ 32 P]-labeled cDNA probe under normal stringent conditions. The blot was visualized by autoradiography

6. 35S:CaSAMDC Col-0 AtUBC10 CaSAMDC #2#3#4#5#6#10 b c d 0 1 2 h Drought CaLEA-1 CaActin CaSAMDC CaDhn CaActin 0 12 24 36 h Cold CaSAMDC CaDhn CaActin 0 1 4 1 4 h ABAMock a ** * Figure S5.

7. Suppl. Fig. S5 Patterns of transcription and PA biosynthesis in response to abiotic stresses in aerial parts of hot pepper (Capsicum annum) and transgenic Arabidopsis plants overexpressing CaSAMDC. a Semi-quantitative RT-PCR analysis of CaSAMDC, CaLEA-1, and CaDhn transcription after drought stress (upper panel), cold stress (middle panel), and ABA treatment (lower panel) using total RNAs from aerial parts of hot pepper. CaActin was used as an equal loading control. b Semi-quantitative RT-PCR analysis of CaSAMDC transcription in WT (Col-0) and CaSAMDC-overexpressing Arabidopsis plants without stress treatment. Total RNA from each Arabidopsis line was used, and AtUBC10 was used as a loading control. Primers used in RT-PCR analyses are listed in Suppl. Table S1. c Changes in SAMDC activity in WT and transgenic Arabidopsis plants (#2 and #4). SAMDC activity was measured in the aerial parts of 2-week-old Arabidopsis seedlings without any abiotic stress. SAMDC activity is shown as the mean ± SD. Asterisk indicates significant difference at P < 0.06 when comparing data by Student’s t test for each measurement between WT and transgenic plants (#2 and #4). d Changes in PA levels in WT and transgenic Arabidopsis plants (#2 and #4). PAs were measured in the aerial parts of 2- week-old Arabidopsis plants without any abiotic stress. Total PA level is the sum of three PA levels. PAs levels are shown as the meas ± SD. Put, putrescine; Spd, spermidine; Spm, spermine. Asterisk indicates significant difference at one (P < 0.05) or two (P < 0.01) when comparing data by Student’s t test for each measurement between WT and transgenic plants (#2 and #4)

8. 11 days without watering 3-week-old plants 3 days after re-watering 35S::CaSAMDC 20 % (8/40) 90 % (33/40) 65 % (26/40) 6 0% (24/40) 50 % (20/40) Col-0#2#4#5#10 a b * ** * * * Suppl. Fig. S6

9. Suppl. Fig. S6 Phenotypic analyses of WT and CaSMADC-overexpressing transgenic plants in response to drought stress. a Drought tolerance of WT and transgenic plant lines #2, #4, #5, and #10. WT and transgenic plants were grown under normal growth conditions for 3 weeks and then exposed to drought stress by withholding water for 11 days. Surviving plants were counted 3 days after rewatering. b Water contents of detached leaves from transgenic Arabidopsis plants that were incubated at room temperature under dim light. Reduction of fresh weights was measured at the indicated time points. Water loss rates were estimated as the percentage of initial to final fresh weights. Data are shown as the mean ± SD. Asterisk indicates significant difference at one (P < 0.05) or two (P < 0.01) when comparing data by Student’s t test for each measurement between WT and transgenic plants (#2 and #4)