20
Transcriptional and post-transcriptional gene regulation during abiotic & biotic stresses in plants. By Sarbesh D. Dangol Nigde, Turkey. December 10, 2015. 12/10/2015 Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

Biotic abiotic transcriptional post transcriptional regulation

Embed Size (px)

Citation preview

Page 1: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

Transcriptional and post-transcriptional gene

regulation during abiotic & biotic stresses in plants.

By Sarbesh D. DangolNigde, Turkey.

December 10, 2015.12/10/2015

Page 2: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

Biotic/Abiotic stresses in plants

Stresses seriously reduce plant productivity.

Induces molecular events for cellular adaptation.

Involves transcription factors, kinase cascades, and reactive oxygen species (ROS).

Crosstalk enhances plant’s resistance against pathogens.

12/10/2015

Page 3: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

Abiotic stress can induce biotic tolerance in plants and vice-versa

• Timely perception of stress.• Cross-tolerance: multiple stress cause plants to defend

themselves facing one stress and makes more resistant to other stresses.

• On drought stress, reduced infection of tomato by Botrytis cinerea and Oidium neolycopersici.

• Ozone exposure can induce resistance to virulent Pseudomonas syringae strains in Arabidopsis.

• Pathogenic wounding increases salt tolerance in tomato.

12/10/2015

Page 4: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

Biotic/Abiotic stresses in plants

• Callose accumulation, changes in ions fluxes, ROS, and phytohormones are induced.

• Results in signal transduction that triggers metabolic reprogramming towards defense.

12/10/2015

Page 5: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

Reactive Oxygen Species (ROS)

• The production of ROS is fine-modulated by the plant to avoid tissue damage.

• While high levels of ROS lead to cell death, lower levels are mostly responsible to regulate the plant’s stress responses.

• ROS might attenuate the oxidative stress caused by abiotic stress.

12/10/2015

Page 6: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

MAPK cascades

• MAPK pathways activated by pathogen attack. • Mediated by SA/ ABA, and the resulting

expression of PR genes induces defense reactions.

12/10/2015

Page 7: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

Abscisic acid (ABA)• Higher levels of ABA after Pst DC 3000 infection. • Suppression of other defense responses.

• Positive effect of ABA on biotic and abiotic stress resistance.

• Controversial molecule -- “good to bad”

depending on environmental conditions.12/10/2015

Page 8: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

Transcription Factors and Molecular Responses in Cross-Tolerance

• Specific phytohormones (ABA, SA, JA, and Ethylene) mediate activity of PR genes.

• ABA and JA induces BOS1 gene and gives resistance against osmotic stress and necrotrophic pathogens.

• bos1 mutant plants are more susceptible to both stresses.

12/10/2015

Page 9: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

PR genes

• PR genes are induced on plant’s exposure to abiotic stress ensuring disease resistance.

• Over-expression of TFs confronted with cold stress and infection activates cold-responsive PR genes.

• Upregulation of TFs after exposure to abiotic stress leads to an accumulation of PR proteins.

• CBF, DREB and NAC are TFs that confer tolerance under abiotic stresses.

12/10/2015

Page 10: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

12/10/2015

PR genes upregulation during stresses

Page 11: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

12/10/2015

Cross-signaling

Page 12: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

12/10/2015

Page 13: Biotic abiotic transcriptional post transcriptional regulation

12/10/2015 Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

TranscriptionalRegulation During abiotic stress

Page 14: Biotic abiotic transcriptional post transcriptional regulation

Central dogma

12/10/2015Sarbesh D. Dangol, PhD Agricultural

Genetic Engineering

Page 15: Biotic abiotic transcriptional post transcriptional regulation

12/10/2015Sarbesh D. Dangol, PhD Agricultural

Genetic Engineering

Post-transcriptionalregulation during abiotic stress

Page 16: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

12/10/2015

Post-transcriptional regulation

Page 17: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

12/10/2015

Post-transcriptional regulation during Geminivirus infection

Page 18: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

12/10/2015

Geminivirus tries to antagonize plants’ stress response

Page 19: Biotic abiotic transcriptional post transcriptional regulation

12/10/2015

Sarbesh D. Dangol, PhD Agricultural Genetic

Engineering

Post transcriptional regulation during Agrobacterium infection

Page 20: Biotic abiotic transcriptional post transcriptional regulation

Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

Thank you. 12/10/2015