1. Louis et al. Figure S1 Mean expression intensity Figure S1. MPL1 expression in Arabidopsis organs The Genevestigator tool (http://www.genevestigator.com/) was used to analyze publicly available microarrays for MPL1 (At5g14180) expression level in the indicated Arabidopsis organs and developmental stages.http://www.genevestigator.com/

2. Louis et al. Figure S2 Figure S2. GPA-induced expression of MPL1 in the SA deficient ics1 ics2 mutant plant. RT-PCR analysis of MPL1 expression in uninfested (-GPA) and GPA-infested (+GPA) WT Col and the ics1 ics2 plants. RNA for RT-PCR analysis was harvested at 3, 6, 12, 24 and 48 hours post infestation (hpi). Expression of the ACT8 gene served as a control for RNA quality and RT-PCR. PCR conditions and the gene-specific primers used are described in the experimental procedures. ACT8 MPL1 ACT8 MPL1 61224483 61224483 -GPA +GPA hpi WT Col ics1 ics2

3. (a) SALK_101919 SALK_082589 50 (ATG) 250 352 471 1545 1685 1783 1893 1997 2140 2364 2443 2530 2625 2237 2277 2699 3021 (TGA) (b) MPL1 ACT8 WT mpl1-1mpl1-2 Louis et al. Figure S3 Figure S3. MPL1 knockout lines. (a) Diagram of the Arabidopsis thaliana MPL1 gene indicating position of the two T-DNA insertion alleles, SALK_101919 (mpl1-1) and SALK_082589 (mpl1-2) in the ninth exon. Exons are represented by boxes and introns by black lines. Black and white boxes indicate coding and non-coding regions, respectively. The start and stop codons are indicated. The numbers indicate nucleotide positions. (b) Reverse-transcription polymerase chain reaction (RT-PCR) analysis of MPL1 gene expression after 40 cycles of PCR amplification. Expression of the ACT8 gene served as a control for RNA quality and RT-PCR. PCR conditions used were as follows: 95°C for 5 min, followed by 40 cycles of 95°C for 30 sec, 55°C for 45 sec, and 72°C for 1 min, with a final extension at 72°C for 5 min. Sequences of the gene-specific PCR primers used are described in the experimental procedures.

4. WT mpl1-1 MPL1 (OE) (#5) (#4) pad4-1 pad4-1 MPL1 (OE) (#6) (#5) Louis et al. Figure S4 Figure S4. mpl1 mutant and MPL1 over-expressing lines do not exhibit growth defects. Comparison of the morphology of 4-week-old wild type Col, mpl1-1, pad4-1, the MPL1 overexpressing (OE) transgenic lines #4 and #5, which are in the mpl1-1 genetic background, and the pad4 MPL1(OE) transgenic lines #5 and #6, which are in the pad4-1 genetic background. All plants were photographed from the same distance.

5. 0 5 10 15 20 25 30 # aphids aa a b Buf WTDiet WT (boiled) Louis et al. Figure S5 Figure S5. Heat sensitivity of the antibiosis factor in Arabidopsis petiole exudates. Artificial diet assay: Comparison of GPA numbers on an artificial diet, the artificial diet containing the buffer (Buf) used to collect petiole exudates, and the artificial diet containing petiole exudates collected from leaves of WT Arabidopsis and WT petiole exudates that had been boiled at 95°C for 10 minutes. Three adult apterous aphids were introduced into each feeding chamber and allowed to feed on the exudates mixed with the artificial diet. The total numbers of aphids (adults + nymphs) in each feeding chamber were determined four days later. Each experiment contained four replicates for each treatment. Error bars represent SE. Different letters above the bars indicate values that are significantly different (P<0.05) from each other. This experiment was repeated twice.

6. Louis et al. Figure S6 (c) 0 5 10 15 20 244872244872 MPL1 (OE) #5 WT MPL1 (OE) #4 Time (h) # aphids (d) 0 10 20 30 244872244872 Time (h) * * * * * * # aphids pad4 MPL1 (OE) #6 WT pad4 MPL1 (OE) #5 (a) 0 5 10 15 20 25 244872 Time (h) WTmpl1-1 # aphids (b) 0 10 20 30 244872 Time (h) *** WTpad4 # aphids Figure S6. Constitutive over-expression of MPL1 does not enhance antixenosis. (a) GPA was given the choice of selecting between the WT and the mpl1-1 mutant. (b) GPA was given the choice of selecting between the WT and the pad4 mutant. (c) GPA was given the choice of selecting between the WT and the MPL1(OE) transgenic lines, which are in the mpl1-1 genetic background. (d) GPA was given the choice of selecting between the WT and the pad4 MPL1(OE) line #5 and #6, which are in the pad4-1 mutant background. 40 adult apterous aphids were released at the center of a pot containing one WT and one mutant or transgenic plant, equidistant from the two plants. The number of the released insects that had settled on each plant was determined 24, 48 and 72 h after release. Values are the average of adult aphid numbers on a minimum of six plants of each genotype for each time point. Error bars represents SE. An asterisk (*) indicates values that are significantly different (P<0.05) between the WT and the mutant or transgenic plant at that particular time point. At none of the time points were statistically significant differences observed between insect numbers on the WT and the mpl1-1 plant, and the WT and the MPL1(OE) transgenics. The experiments in a, b, c and d were conducted simultaneously.

7. Louis et al. Figure S7 Figure S7. Amino acid sequence of MPL1 and homology to key regions of lipases. (a) Amino acid sequence of MPL1. Residues S190, D360 and H393 (all marked in black bold) are likely active site residues based on sequence of other TAG lipases. Underlined sequence GHSLG corresponds to the GXSXG motif, containing the S190. MPL1 contains a signal peptide (underlined with broken lines) at its N- terminus, with a predicted cleavage site between amino acids 31 and 32 (SignalP 3.0; http://www.cbs.dtu.dk/services/SignalP/), suggesting that it is processed through the endoplasmic reticulum. However, whether it is localized to vacuoles or secreted is not known. (b) Conservation of amino acid sequences around the S190, D360 and H393 residues between MPL1 and other well-characterized lipases. Conserved residues are marked with an asterisk (*). MPL1: AtLIP1: Human GL : YLGHSLGTL YGGLDSLADVKDVEKDYAHADFI LVGHSQGTI YGGTDGLADVTDVEEDYGHIDFV YVGHSQGTT NGGKDLLADPQDVGPFYNHLDFI *** ** ** * *** ** * * ** (b) (a) 1 MAGSV MVPSV SIGLA LSVLI FFALS LKTLE ARGTF GRLAG 41 QPPQR TAAGG ICASS VHIFG YKCEE HDVVT QDGYI LNMQR 81 IPEGR AGAVA GDGGK RQPVL IQHGI LVDGM SWLLN PADQN 121 LPLIL ADQGF DVWMG NTRGT RFSRR HKYLN PSQRA FWNWT 161 WDELV SYDLP AMFDH IHGLT GQKIH YLGHS LGTLI GFASF 201 SEKGL VDQVR SAAML SPVAY LSHMT TVIGD IAAKT FLAEA 241 TSILG WPEFN PKSGL VGDFI KAICL KAGID CYDLV SVITG 281 KNCCL NASTI DLFLA NEPQS TSTKN MIHLA QTVRD KELRK 321 YNYGS SDRNI KHYGQ AIPPA YNISA IPHEL PLFFS YGGLD 361 SLADV KDVEF LLDQF KYHDI DKMNV QFVKD YAHAD FIMGV 401 TAKDV VYNQV ATFFK RQA