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Figure Legends
Figure 1: MAMP pre-treatment protects Fv/Fm from bacterial induced suppression. A. Graph quantifying changes inFv/Fm over 23 hpi with DC3000 infection on Col-0 leaves. Blue line represents leaves pre-treated with H2O; orange - pre-treated with chitin (100 µg/ml); dashed grey - leaves pre-treated with flg22 (1 µM) and dashed yellow - leaves pre-treated with elf18 (1 µM). B. 18 hpi imageFv/Fm of a Col-0 plant pre-treated with H2O, chitin (100 µg/ml), flg22 (1 µM) and elf18 (1 µM) at 18 hpi with DC3000. Orange represents normalFv/Fm , whereas yellow/green/blue represents suppressed Fv/Fm .C. Graph quantifying changes inFv/Fm over 24 h following DC3000 infection on Col-0 and efr1 leaves. Blue line represents Col-0 leaves pre-treated with H2O; grey - Col-0 leaves pre-treated with flg22 (1 µM); yellow - Col-0 leaves pre-treated with elf18 (1 µM); green - efr1 leaves pre-treated with H2O; dashed blue - efr1 leaves pre-treated with flg22 (1 µM) and red - efr1 leaves pre-treated with elf18 (1 µM).D. Visual snapshot ofFv/Fm for a Col-0 plant (top right) and efr1 plants pre-treated with H2O, flg22 (1 µM) and elf18 (1 µM) at 18 hpi with DC3000. Orange represents normal Fv/Fm , whereas yellow/green/blue represents suppressedFv/Fm . E. Graph quantifying changes in Fv/Fm over 24 h of DC3000 infection on Col-0 and cerk1-2 leaves. Blue represent Col-0 leaves pre-treated with H2O; orange - Col-0 leaves pre-treated with chitin (100 µg/ml); grey - Col-0 leaves pre-treated with flg22 (1 µM); green - cerk1-2 leaves pre-treated with H2O, red - cerk1-2 leaves pre-treated with chitin (100 µg/ml) and dashed blue - cerk1-2 leaves pre-treated with flg22 (1 µM). F. 18 hpi image ofFv/Fm for Col-0 (top right) andcerk1-2 plants pre-treated with H2O, flg22 (1 µM) and chitin (100 µg/ml) challenged with DC3000. Orange represents normalFv/Fm , whereas yellow/green/blue represents suppressed Fv/Fm . Flg22; flg: chitin; chi: elf18; elf.
Figure 2: MAMP pre-treatment protects Fv/Fm from bacterial induced suppression, with the exception of chitin pre-treatment of fls2 leaves. A. Graph quantifying changes inFv/Fm over 24 hpi with DC3000 on Col-0 and cerk1-2 leaves. Blue line represents Col-0 leaves pre-treated with H2O; yellow - Col-0 leaves pre-treated with elf18 (1 µM); green - cerk1-2 leaves pre-treated with H2O and dashed red line - cerk1-2 leaves pre-treated with elf18 (1 µM) B. Representative visual snapshot of Fv/Fm for a Col-0 plant (top right) and cerk1-2 plants pre-treated with H2O and elf18 (1 µM) at 18 hpi with DC3000. Orange represents normalFv/Fm , whereas yellow/green/blue represents suppressed Fv/Fm .C. Graph quantifying changes inFv/Fm over 24 h of DC3000 infection on Col-0 and efr1 leaves. Blue represents Col-0 leaves pre-treated with H2O; orange - Col-0 leaves pre-treated with chitin (100 µg/ml); green - efr1 leaves pre-treated with H2O and red - efr1 leaves pre-treated with chitin (100 µg/ml) D. Visual snapshot ofFv/Fm for a Col-0 plant (top right) and efr1 plants pre-treated with H2O and chitin (100 µg/ml) at 18 hpi with DC3000. Orange represents normalFv/Fm , whereas yellow/green/blue represents suppressed Fv/Fm .E. Graph quantifying changes inFv/Fm over 24 h of DC3000 infection on Col-0 and fls2 leaves. Blue represent Col-0 leaves pre-treated with H2O; orange - Col-0 leaves pre-treated with chitin (100 µg/ml); grey - Col-0 leaves pre-treated with flg22 (1 µM); green - fls2 leaves pre-treated with H2O; dark blue - fls2 leaves pre-treated with chitin (100 µg/ml) and red - fls2 leaves pre-treated with flg22 (1 µM) F. Image of Fv/Fm for a Col-0 plant (top right) and fls2 plants pre-treated with H2O, chitin (100 µg/ml) and flg22 (1 µM) at 18 hpi with DC3000. Orange represents normal Fv/Fm , whereas yellow/green/blue represents suppressedFv/Fm .
Figure 3: DC3000 is unable to suppress cROS in MAMP pre-treatment leaves . Col-0 leaves treated with the non-specific species stain H2DCF-DA 5.5 hpi with DC3000hrpA and DC3000. Leaves imaged on a Zeiss 880 using excitation at 488 nm, emission window of 512–527 nm to capture the oxidised dichlorofluorescein signal (Green). Chloroplast fluorescence was measured at 659–679 nm (red). Scale bars showing 20 µm. A.H2O pre-treated and DC3000hrpA infectionB. H2O pre-treated and DC3000 infectionC. flg22 (1 µM) pre-treated and DC3000 infection D.elf18 (1 µM) pre-treated and DC3000 infection. Image representative of three biological replicates.
Figure 4: Bacterial MAMP pre-treatments provide full and partial protection on bkk1-1 andbak1-5 single mutant lines but fail to protectbak1-5/bkk1-1 lines. A. Graph quantifying changes inFv/Fm over 23 h of DC3000 infection on Col-0 and bkk1-1 leaves. Blue line represents Col-0 leaves pre-treated with H2O; grey - Col-0 leaves pre-treated with flg22 (1 µM); yellow - Col-0 leaves pre-treated with elf18 (1 µM); green dashed line - bkk1-1 leaves pre-treated with H2O; dark blue - bkk1-1 leaves pre-treated with flg22 (1 µM); red - bkk1-1 leaves pre-treated with elf18 (1 µM)B. Image, 18 hpi with DC3000, ofFv/Fm for Col-0 (top right) andbkk1-1 plants pre-treated with H2O and flg22 (1 µM). C. Image, 18 hpi with DC3000, ofFv/Fm for Col-0 (top right) andbkk1-1 plants pre-treated with H2O and elf18 (1 µM). Orange represents normalFv/Fm , whereas yellow/green/blue represents suppressed Fv/Fm .D. Graph quantifying changes inFv/Fm over 23 hpi with DC3000 on Col-0 and bak1-5 leaves. Blue represents Col-0 leaves pre-treated with H2O; grey - Col-0 leaves pre-treated with flg22 (1 µM); yellow - Col-0 leaves pre-treated with elf18 (1 µM); green -bak1-5 leaves pre-treated with H2O; dark blue -bak1-5 leaves pre-treated with flg22 (1 µM) and red corresponds to bak1-5 leaves pre-treated with elf18 (1 µM) E. Image at 18 hpi with DC3000, of Fv/Fmfor Col-0 (top right), bak1-5 (top left) or bak1-5/bkk1-1(bottom), plants pre-treated with H2O and flg22 (1 µM).F. Image, 18 hpi with DC3000, ofFv/Fm for Col-0 (top right),bak1-5 (bottom) or bak1-5/bkk1-1 (top left), plants pre-treated with H2O and elf18 (1 µM) at 18 hpi with DC3000. Orange represents normalFv/Fm , whereas yellow/green/blue represents suppressed Fv/Fm .G. Quantitative changes inFv/Fm over 23 hpi with DC3000 on Col-0 and bak1-5/bkk1-1 leaves. Blue represents Col-0 leaves pre-treated with H2O; grey - Col-0 leaves pre-treated with flg22 (1 µM); yellow - Col-0 leaves pre-treated with elf18 (1 µM); green - bak1-5/bkk1-1 leaves pre-treated with H2O; dark blue - bak1-5/bkk1-1 leaves pre-treated with flg22 (1 µM) and red represents bak1-5/bkk1-1 leaves pre-treated with elf18 (1 µM).
Figure 5: DAMP pre-treatment restricts suppression ofFv/Fm following bacterial challenge. A. Graph quantifying changes inFv/Fm over 24 hpi following DC3000 infection of Col-0. Blue represents leaves pre-treated with H2O; orange - pre-treated with Pep1 (1 µM); dashed grey - pre-treated with Pep2 (1 µM) and yellow represents pre-treated with Pep3 (1 µM). B. Image ofFv/Fm in Col-0 plants pre-treated with H2O, Pep1 (1 µM), Pep2 (1 µM) or Pep3 (1 µM) at 18 hpi with DC3000. Orange represents normalFv/Fm , whereas yellow/green/blue represents suppressed Fv/Fm .C. Graph quantifying changes inFv/Fm over 24 hpi with DC3000 on Col-0 and pepR1-1x1-2 leaves. Blue represents Col-0 leaves pre-treated with H2O; orange - Col-0 pre-treated with pep1 (1 µM); yellow - Col-0 pre-treated with pep3 (1 µM); red -pepR1-1x1-2 pre-treated with H2O; dark blue -pepR1-1x1-2 pre-treated with pep1 (1 µM) and green representspepR1-1x1-2 leaves pre-treated with pep3 (1 µM). D.Image of Fv/Fm for Col-0 (right) and pepR1-1x1-2 pre-treated with H2O, Pep1 (1 µM), and Pep3 (1 µM) 18 hpi with DC3000. Orange represents normalFv/Fm , whereas yellow/green/blue represents suppressed Fv/Fm .E. Graph quantifying changes inFv/Fm over 24 hpi with DC3000 on Col-0 and pepR1-1x1-2 leaves. Blue represents Col-0 leaves pre-treated with H2O; grey - Col-0 leaves pre-treated with flg22 (1 µM); red - pepR1-1x1-2 leaves pre-treated with H2O and dark blue - pepR1-1x1-2 leaves pre-treated with flg22 (1 µM). F. Representative image, 18 hpi with DC3000, of Fv/Fm for Col-0 (right) and pepR1-1x1-2 plants pre-treated with H2O and flg22 (1 µM). Orange represents normalFv/Fm , whereas yellow/green/blue represents suppressed Fv/Fm .
Figure 6: High light enhances bacterial suppression ofFv/Fm. A. Graph quantifying changes in Fv/Fm over 24 hpi of DC3000 (blue line) and DC3000hrpA (orange line) infection on Col-0 leaves under normal light (NL) (120 µmol m-2s-1). B. Image ofFv/Fm at 23 hpi of Col-0 plants with DC3000 and DC3000hrpA under NL (120 µmol m-2s-1). Orange represents the expected Fv/Fm , whereas yellow/green/blue represents suppressedFv/Fm . C. Graph quantifying changes in Fv/Fm over 26.5 hpi of DC3000 (blue line) and DC3000hrpA (orange line) infection on Col-0 leaves under high light (HL) (650 µmol m-2s-1). D. Image ofFv/Fm at 22.75 hpi of Col-0 plants with DC3000 and DC3000hrpA under HL (650 µmol m-2s-1). Unlabelled leaves are not infiltrated. Orange represents expectedFv/Fm , whereas yellow/green/blue represents suppressed Fv/Fm .E. Graph quantifying changes inFv/Fm over 26.5 hpi of DC3000 on Col-0 under high light (HL) (650 µmol m-2s-1). Blue represents Col-0 leaves pre-treated with H2O; grey - Col-0 leaves pre-treated with flg22 (1 µM) and the yellow line represents Col-0 leaves pre-treated with elf18 (1 µM). F. Image ofFv/Fm for Col-0 plants pre-treated with H2O, flg22 (1 µM) and elf18 (1 µM) at 22.75 hpi with DC3000 under HL (650 µmol m-2s-1). Orange represents expected Fv/Fm , whereas yellow/green/blue represents suppressedFv/Fm . G. Graph quantifying changes in Fv/Fm over 26.5 hpi of Col-0 and bak1-5/bkk1-1 leaves with DC3000 under high light (HL) (650 µmol m-2s-1). Blue represents Col-0 and red bak1-5/bkk1-1 leaves H. Image of Fv/Fm 22.75 hpi with DC3000 on Col-0 plant (right) or bak1-5/bkk1-1 plants under HL (650 µmol m-2s-1). Orange represents expected Fv/Fm , whereas yellow/green/blue represents suppressedFv/Fm .
Figure 7: High light renders Col-0 and bak1-5/bkk1-1 plants more susceptible to bacterial infection. Bacterial growth of DC3000 on Col-0, fls2and bak1-5/bkk1-1 plants under normal light (NL; blue; 120 µmol m-2s-1) and high light (HL; red; 450 µmol m-2s-1). Error bars, mean ± SE (n=6), student t-test determined statistical significance of P < 0.0001 for NL Col-0 vs fls2 and Col-0 vsbak1-5/bkk1-1 (not shown on graph), HL Col-0 vsbak1-5/bkk1-1, Col-0 NL vs HL, bak1-5/bkk1-1 NL vs HL. There was no significant difference between HL Col-0 vs fls2 andfls2 NL vs HL. Representative of three biological replicates.
Figure 8: Exogeneous ABA synergistically or antagonistically alters pathogen induced ABA suppression of Fv/Fm in a concentration dependent manner. A. Graph quantifying changes inFv/Fm over 24 hpi following DC3000 or DC3000hrpA infection of Col-0, aao3 andabi1/abi2/hab1 leaves. Blue represents Col-0 leaves infiltrated with DC3000; red - Col-0 leaves infiltrated with DC3000hrpA ; grey - aao3 leaves infiltrated with DC3000; yellow - aao3leaves infiltrated with DC3000hrpA ; dark blue -abi1/abi2/hab1 leaves infiltrated with DC3000 and green corresponds to abi1/abi2/hab1 leaves infiltrated with DC3000hrpA . B. Image ofFv/Fm of Col-0, aao3 andabi1/abi2/hab1 plants 18 hpi with DC3000 or DC3000hrpA . Orange represents normal Fv/Fm readout, whereas yellow/green/blue represents suppressedFv/Fm . C. Bacterial growth of DC3000 on Col-0, aao3 or abi1/abi2/hab1 plants under normal light (NL; 120 µmol m-2s-1; blue) or high light (HL; 450 µmol m-2s-1; orange) conditions. Error bars, mean ± SE (n=6) student t-test determined statistical significance of P < 0.0001 for Col-0 NL vs HL (shown), statistical significance of P < 0.001 for aao3 NL vs HL and statistical significance of P < 0.005 for HL Col-0 vsabi1/abi2/hab1 . Representative of three replicated experiments.D. Graph quantifying changes in Fv/Fm 24 hpi with DC3000 on Col-0 leaves in the presence of ABA under normal light (NL; 120 µmol m-2s-1). Blue - Col-0 leaves infiltrated with DC3000 and orange - Col-0 leaves co-infiltrated with DC3000 + 10 µM ABA. E. Image ofFv/Fm of Col-0, plants 18 hpi infiltrated with DC3000 and co-infiltrated with DC3000 and 10 µM ABA under NL. Orange represents expectedFv/Fm , whereas yellow/green/blue represents suppressed Fv/Fm .F. Graph quantifying changes inFv/Fm up to 24 hpi with DC3000 of Col-0 leaves in the presence of increasing concentrations of ABA under high light (HL; 650 µmol m-2s-1). Blue represents Col-0 leaves infiltrated with DC3000; orange - Col-0 leaves co-infiltrated with DC3000 + 10 µM ABA and grey corresponds to Col-0 leaves co-infiltrated with DC3000 + 100 µM ABA. E. Image, 19.5 hpi, of Fv/Fm of Col-0 infiltrated with DC3000, co-infiltrated with DC3000 and 10 or 100 µM ABA under HL. Orange represents expectedFv/Fm , whereas yellow/green/blue represents suppressed Fv/Fm .
Figure 9: Schematic overview of findings from study. Black arrows show pathways to normalFv/Fm while red arrows show pathways to suppressed Fv/Fm or increased bacterial growth. A. MAMP pre-treatment followed by DC3000 infection on receptor mutant plants. fls2 leaves pre-treated with elf18 maintain normalFv/Fm while fls2 leaves pre-treated with chitin, Pep1 or 2 show suppressedFv/Fm . efr1 leaves pre-treated with flg22 or chitin maintain normalFv/Fm . cerk1-2 leaves pre-treated with flg22 or elf18 maintain normalFv/Fm . PepR1-1x2-1 leaves with flg22 maintain normal Fv/Fm .B. MAMP pre-treatment followed by DC3000 infection on MTI co-receptor mutant plants. bak1-5 leaves pre-treated with flg22 or elf18 maintain normal Fv/Fmwhile bak1-5 leaves pre-treated with chitin show suppressedFv/Fm . bkk1-1 leaves pre-treated with flg22, elf18 or chitin maintain normalFv/Fm . bak1-5/bkk1-1leaves pre-treated with flg22, elf18, chitin, Pep1 or 2 show suppressedFv/Fm . Under high light (HL) conditions (dashed red line) bak1-5/bkk1-1 leaves show an increased suppression of Fv/Fm(thick, red dashed arrow) and increased bacterial growth compared to normal light (NL) conditions. C. Chlorophyll fluorescence and bacterial growth are altered under different light conditions. Under normal light (NL; 120 µmol m-2s-1) conditions DC3000hrpA infected leaves maintain normalFv/Fm , while DC3000 infected leaves show suppressed Fv/Fm . Pre-treatment of Col-0 leaves with flg22 or elf18 under NL results in normal Fv/Fm . Under high light (HL; 650 µmol m-2s-1) DC3000hrpA , DC3000 and flg22 or elf18 pre-treated DC3000 infected leaves all show suppressed Fv/Fmand DC3000 infected leaves show an increase in bacterial growth.D. Chlorophyll fluorescence is reduced during high light and ABA treatment. Under normal light (NL; 120 µmol m-2s-1) conditions DC3000 infected leaves and leaves co-infiltrated with DC3000 + 10 µM show suppressedFv/Fm . Under high light (HL; 650 µmol m-2s-1) leaves infected with DC3000, leaves co-infiltrated with DC3000 + 10 µM and leaves co-infiltrated with DC3000 + 100 µM all showed suppressedFv/Fm . Created with BioRender.com.