Revealing a polyamine-ethylene regulatory node linked to drought resistance/susceptibility in oat.

Transcription

1 Revealing a polyamine-ethylene regulatory node linked to drought resistance/susceptibility in oat. Gracia Montilla-Bascón, Francisco José Canales, Luis AJ Mur, Elena Prats Institute of Sustainable Agriculture Spanish National Research Council (CSIC)

2 Biotic and abiotic stresses: The external conditions adversely affect growth, development and productivity of the plants Water stress Powdery mildew Blumeria graminis f. sp. avenae Crown rust Puccinia coronata f. sp. avenae Breeding programmes improve the yield, quality and economic productivity of this crop.

3 Abiotic stresses: Drought Effects on crop growth and yield Effects drought on plants Assimilation partitioning Nutrients: availability, uptake, translocation, and metabolism. Water relations: RWC, leaf water potential, stomatal resistance, etc. Photosynthesis.

4 Mechanism of adaptation to drought stress Shortening of the crop duration to complete life cycle before stress. Increasing its ability to avoid damage by keeping the water content high in the plants tissues. Maintenance of metabolic functions under water limiting

5 Oat is specially sensitive to drought stress Oats have an important root system that explores the soil well, however Transpiration rates higher than in other small grain cereals (i.e. Ehlers, 1989; Coffman and Frey, 1961; Peltonen-Sainio, 1999). Higher water requirements than other small grain cereals Especially susceptible to grain abortion caused by drought and heat Drought Resistance Important target. But low heritability and high GxE

6 PATONES (TOLERANT) FLEGA (SUSCEPTIBLE) Drought resistance mechanisms in oat Early stomatal closure Stomatal collapse Low CO 2 availability Massive ROS Membrane damage Membrane disrupted Early proline production Proline accumulation Increased proline content 45% 25-35% 2% srwc Fine stomatal regulation Early ROS scavenging Late stomatal closure CO 2 availability ROS scavenging Effective ROS scavenging H 2 O 2 H 2 O 2 H 2 O 2 Membrane stabilisation H 2 O 2 Membrane stabilisation Proline accumulation at later stages Ascorbate CO 2 Proline Salicylate Sugars

7 (Obtained from Desikan, R. et al., 23) Nitric oxide (NO) Haemoglobin, scavenging of NO (Hb/NO cycle) Barley non-symbiotic gen HvHb1 oxides NO to NO 3 - NO level s Drought resistance WT (Golden Promise) UHb Overexpressing HvHb1 gen

8 Quantification of NO in vivo in barley Institute of Molecules and Materials Radboud University WT (Golden Promise) HHb Overexpressing HvHb1 gen Monitorized NO during drought cycle (18 days) Air with NO from plant 1 l/h Spectrophotometer based on QCL (quantum cascade laser) Air without NO 3 l/h 2 l/h

9 Visual scale NO production (Percent resp WT Cont) Quantification of NO in vivo in barley ** * HHb plants produce less NO than WT *** Differences more pronunciated under drought conditions WT Cont WT Drought HHb Cont HHb Drought Grafica Nº3 del articulo de cebadas WT HHb Days after withholding water Genotypes WT HHb Area under the disease progress curve WT is more susceptible to drought than plants overexpresing HvHb1 gen and therefore, containing less NO

10 Patones (tolerant) Flega (susceptible) First question?? srwc 1% 55-6% 4-45% 3-35% 2-25% 15-2% Controls daww

11 NO production (% of the control) Visual Scale Quantification of NO in vivo in oat AUDPC Flega (susceptible) Patones (tolerant) Days after witholding water Resistant genotype produce significantly less NO during drought cycle ns * * * ns 9-95% 6-65% 4-45% 25-3% 15-2% Soil Relative Water content

12 May NO influence drought resistance through polyamine pathway???? Proline -Pyrroline-5- carboxylate Glutamate-γ semialdehide N 2 NO 3 NR NO 2 NR NiR NiR NH 3 GlnS Glutamate GluS Glutamine Glutamate α-ketoglutarate Glutamate GluDC NO Lysine γ-aminobutiric acid (GABA) Aspartate semialdehyde 1 -Pyrroline TCA cycle Norspermidine DAO H 2 O 2 + NH 3 1,3-Diaminopropane (DAP) PAO Spermine PAO SpmS Spermidine PAO SpmS O 2 Putrescine ODC L-ornithine O 2 H 2 O 2 MTA Decarboxylated S- Adenosylmethionine (dcsam) AdoMetDC MTA Agmatine ADC Citruline L-Arginine Ethylene ACO Aminocyclopropane carboxylic acid (ACC) ACS S-Adenosylmethionine (SAM) Citruline? + NO MAT Methionine

13 µmol g -1 dry weight Polyamines quantification by HPLC 18 Put Spd Spm Cnt Drg Flega Agm DAP Cnt Drg Patone s 4 2 Cnt Drg Flega Cnt Drg Patone s Significant differences in PAs content between both genotypes.

14 Ethylene???? Proline -Pyrroline-5- carboxylate Glutamate-γ semialdehide N 2 NO 3 NR NO 2 NR NiR NiR NH 3 GlnS Glutamate GluS Glutamine Glutamate α-ketoglutarate Glutamate GluDC NO Lysine γ-aminobutiric acid (GABA) Aspartate semialdehyde 1 -Pyrroline TCA cycle Norspermidine DAO H 2 O 2 + NH 3 1,3-Diaminopropane (DAP) PAO Spermine PAO SpmS Spermidine PAO SpmS O 2 Putrescine ODC L-ornithine O 2 H 2 O 2 MTA Decarboxylated S- Adenosylmethionine (dcsam) AdoMetDC MTA Agmatine ADC Citruline L-Arginine Ethylene ACO Aminocyclopropane carboxylic acid (ACC) ACS S-Adenosylmethionine (SAM) Citruline? + NO MAT Methionine

15 nl / hour Quantification of Ethylene in vivo in oat Spectrophotometer based on QCL (quantum cascade laser) Air with Ethylene from plant Air without Ethylene 1 l/h 3 l/h 2,5 Ethylene production 2 l/h 2 1,5 Control conditions; 1,5 Flega Patones Resistant genotype emitted more Ethylene

16 % reduction respect Cnt Quantification of Ethylene in vivo in oat Reduction of Ethylene emission respect Control (well-watered plants) at 35% RWC Flega Patones Resistant genotype reduces significantly the Ethylene production respect its control under drought

17 Next step In progress gene expression analysis -ADC -ACS -AdoMetDC -MAT -ODC

18 Contributors: - Dr. Elena Prats - PhD. Francisco Canales - Dr. Luis A.J. Mur - Simona Cristescu