Physiological and biochemical characteristics in plants stressed by high temperature

1. Physiological and biochemical characteristics in plants stressed by high temperature Tae Wan Kim Department of Plant Resources Science, Hankyong National University http://www.hortilover.net/

2. Fig. 1. Schematic global climatic change and plant adaptation

4. I. Primary metabolism

5. Fig. 2. Changes in primary metabolism under high temperature stress.

6. Fig. 3. Temperature response of respiration (R). Assuming a rate of R of 0.5 at 0oC(arbitrary units), R at other temperatures was redicted assuming a linear decline in the Q10 with increasing temperature.

7. Fig. 4. Theoretical examples of two types of acclimation. (a) Type I and (b) Type II, and (c) their effects on the positive feedback respiration (R) might play in determining future atmospheric concentrations of CO2 and global surface temperatures via the greenhouse effect.

8. Fig. 5. Q10of foliar respiration rates of plants in relation to short-term measurement temperature.

9. II. Morphological & Cellular Change

10. ▶Photosynthetic architecture ♣Expansion of thylakoid lumen ♣ Decrease in stacked grana ▶Decrease in mitochondrial cristae ▶Degradation of cytoplasm ▶Expansion of endoplasmic reticulum ▶Disorganization of cell wall fibrillar material

11. Fig. 6. Schematic diagram of protein folding and degradation in high temperature stressed plant cell.

12. III. Chloroplast

13. Measuring flashes have little actinic effects 750 LED’s are on for 10-200 ms Only few PSII RC’s are excited Fluorescence QA- Yet, sufficient fluorescence emission is produced to capture an image

14. Fig. 7. Kautsky and Hirsch (1931) irradiated a dark-adapted leaf with a blue light and observed it visually through a dark-red glass. Here is a high-tech presentation of what they saw.

15. QA- QA- QA- QA- QA- QA- In fluorescence, the actinic light elicits in plants the Kautsky effect of fluorescence induction. FPEAK to FPEAK with mostly closed PSII RC’s F0 from F0 with open PSII RC’s

16. Fig. 8. Fluorescence emission and excitation spectra of barley leaves at selected temperatures.

17. Fig. 10. Effect of heat stress on expression of Rubisco and Rubisco activase. The abundances of Rubisco small subunit (RbcS) and Rubisco activase (rca) mRNA were determined by Northern blot analysis. The de novo synthesis of Rubisco activase and Rubisco large subunit (LSU) were determined by short-term 35S-labelling. Fig. 9. Measured and predicted response of net photosynthesis to leaf temperature in cotton leaves at different internal partial pressures of CO2 (Ci) and O2 concentrations. Net photosynthesis was determined at 210 (*) or 10 mbar O2 (&)at 280 (A) or 1200 (B) mbar Ci.

18. Fig. 11. Western blotting analysis of degradation from PsaA and PsaB proteins. Leaf samples were respectively treated by HL (A, D); LL + D + HT (B, E); and HL + D + HT (C, F).

19. Fig. 12. (A) SDS–PAGE analysis of PSII-enriched particles isolated from stressed leaves of broad bean (24 h stress in cut plants). (B) Immunoblotting raised against D1 polyclonal antibodies. The experiments were performed at least three times and reproducible patterns were obtained.

20. Barley shoot 24 OC 24 OC Fig. 13. Coomassie G-250 stained 2D-PAGE gels of the soluble protein fractions of (a) the Mandolina cultivar, 24oC; (b) the Jubilant cultivar, 24oC; (c) the Mandolina cultivar, 40oC and (d) the Jubilant cultivar, 40oC. 40 OC 40 OC

21. Fig. 14. Distribution of chloroplast proteases. The thylakoid membrane is shown in cream. The serine proteases ClpP, DegP and SppA are shown in dark red, and the metalloproteaseFtsH in purple. The ATPases ClpC (green) and FtsH are indicated. The transmembrane helices of FtsH are shown as purple cylinders. The oligomeric forms of DegP proteins are suggested by the structure of the bacterial and mitochondrial [50] homologs. It is currently not known whether ClpP, FtsH and DegP proteins form homo- or hetero-oligomers.

22. Table 1. Summary of the major protease families in chloroplasts of Arabidopsis

23. 20 oC 40 oC Fig. 15. Topographic image of starch granules in barley endosperm by atomic force microscope (AFM).

24. IV. Mitochondria ▶Decrease in cristae ? ▶ Respiration ?

25. Table 2. Five major classes of plant Hsps/molecular chaperones and their subfamilies, including specific examples for direct involvement of Hsps/molecular chaperones in plant tolerance to stress

26. Decrease in mitochondrial cristae ??? Fig. 16. Driving forces of protein translocation in mitochondria. (A) Proton pumping by the respiratory chain depletes the matrix of positive charges and generates an electrochemical gradient across the inner membrane (IM). The electric membrane potential (Dw) generates an electrophoretic force on the predominantly positively charged presequence once the preprotein in transit has crossed the outer membrane (OM). (B) ATP hydrolysis by matrix Hsp70 provides the necessary energy for the complete translocation of the bulk polypeptide chain. Ssc1 forms a translocation motor in cooperation with the inner membrane protein Tim44 and the nucleotide-exchange factor Mge1. TOM: Translocase of the outer membrane; TIM17/23: Translocase of the inner membrane, consisting of Tim17 and Tim23.

28. ▶Hsp70 : a chaperone of life and death protection of mitochondrial membrane polarity ▶ATP production : key determinants in the choice between cell survival and cell death or death by apoptosis or necrosis. ▶ Protection from cell death in thermotolerant cells may reflect Hsp70/Hsc70-related mitochondrial protection and maintenance of ATP levels.

29. V. Heat Shock Proteins & Chaperones

30. Expression of heat shock proteins(HSPs)

31. Expressed heat shock proteins(HSPs) 1. Hsp100, Hsp90, Hsp70, Hsp60 2. sHsp : small HSP abundantly induced in plants, 3. ubiquitin : ca 8 kDa 4. heat shock transcription factor (HSF) : through binding to the heat shock element (HSE), a consensus sequence in the promoter region of all hsp genes.

32. Table 1. Five major classes of plant Hsps/molecular chaperones and their subfamilies, including specific examples for direct involvement of Hsps/molecular chaperones in plant tolerance to stress

33. Figure 17. The heat-shock protein (Hsp) and chaperone network in the abiotic stress response. Different classes of Hsps/chaperones play complementary and sometimes overlapping roles in protecting proteins from stress. Abiotic stress in plants often causes dysfunction/denaturation of structural and functional proteins. Maintaining proteins in their functional conformations and preventing the aggregation of non-native proteins are particularly important for cell survival under stress conditions. To maintain cellular homeostasis, some members of the Hsp/chaperone families [e.g. small Hsp (sHsp) and Hsp70] stabilize protein conformation, prevent aggregation and thereby maintain the non-native protein in a competent state for subsequent refolding, which is achieved by other Hsps/chaperones

34. Fig. 18. (a) TaHsp16.9A-CI dimer. Monomers with two distinct conformations were observed in the oligomer and are shown in red and green. The N-terminal arm from the green monomer is shown in pale green—the corresponding residues from the red monomer were disordered. The swapped loop donated by the green monomer is indicated in cyan, and the corresponding loop from the red monomer in pink. The C-terminal extensions are shown in yellow and orange. (b) TaHsp16.9A-CI oligomer. Within the dodecamer, the dimers are arranged in two coaxial rings.

35. Fig. 19. Northern hybridisations of the mRNAs obtained from the seeds of durum wheat grown under controlled conditions. The probes used are those for hsp70, hsp26.6, hsp17 and 18S rRNA.

36. Table 2. Expression of sHsps in conditions other than heat stress

37. VI. Secondary & other Metabolism

39. Fig. 20. A schematic depiction of the biosynthetic pathway that leads to isoprene ormation inplants. Abbreviations: CDP-ME, 4-(cytidine 59-diphospho)-2-C-methyl-D-erythritol; CDPME2P, 2-phospho-4-(cytidine 59-diphospho)-2-C-methyl-D-erythritol; DMAPP, dimethylallyl diphosphate; DOXP, 1-deoxy-D-xylulose-5-phosphate; GA-3-P, glyceraldehyde-3-phosphate; IPP, isopentenyl pyrophosphate; MECDP, 2-C-methyl-D-erythritol 2,4-cyclodiphosphate; MEP, 2-C-methyl-D-erythritol-4-phosphate; MVA, mevalonic acid.

40. Fig. 21. Induction of secondary metabolites under HTS.

41. Fig. 22. Basic PRX profiles of the leaf tissues from unstressed-control (C), gradual heat stressed (GHS) and shock heat stressed (SHS) plants. Samples: (1) 30 ◦C; (2) 35 ◦C; (3) 40 ◦C; and (4) 45 ◦C.

42. Fig. 23. Relative specific activities (standard error) of GST, GR, APOX, CAT and SOD extracted from leafy spurge plants exposed to 41°C up to 48 h.

43. Fig. 24. Effect of high temperature on leaf electrolyte leakage rate of strawberry plants exposed to gradual (GHS) and shock (SHS) heat stress. Values are means from three replications and vertical bars indicate ±S.E.

44. Fig. 25. Lipid composition of leaves for three cultivars of creeping bentgrass at 35 ◦C. (A–C) Percentage of each lipid species at time = 0, 7, 28 days, respectively. (D–F) Changes in specific lipid species over time: linolenic, linoleic and palmitic acids, respectively.

45. Fig. 26. Physiological changes of heat-acclimated (30 ◦C) Penncross plants during heat stress (35 ◦C). (A) Turf quality, (B) TBARS, (C) amino acid leakage, (D) total chlorophyll content.

46. Table 3 . Effects of high temperature and water-logging on the release of 15N at different growth stages

47. Fig. 27. Dynamics of oil accumulation in peripheral grains of capitulae exposed to increased temperature during three 7-day intervals during grain filling in Helianthus annus.

48. Fig. 28. Evolution of linoleic and oleic fatty acid percentages (of total lipids) for peripheral grain of capitulae exposed to increased temperature during two 7-day intervals during grain filling in sunflower

49. Table 3. Comparison of measured monoterpene mix (in % of the monoterpenes totally detected)

50. Fig. 30. Crop stomatal resistance (sm−1) vs. air temperature (oC) measured during June and July 1997. Modified Pennman function λE=0.485(1 − exp.−0027P))Rs + 751DP