biotic abiotic transcriptional post transcriptional regulation

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Transcriptional and post-transcriptional gene regulation during abiotic & biotic stresses in plants.By Sarbesh D. DangolNigde, Turkey.December 10, 2015.

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

Biotic/Abiotic stresses in plantsStresses seriously reduce plant productivity.

Induces molecular events for cellular adaptation.

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

Crosstalk enhances plants resistance against pathogens.

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

Abiotic stress can induce biotic tolerance in plants and vice-versaTimely 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.

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

Biotic/Abiotic stresses in plantsCallose accumulation, changes in ions fluxes, ROS, and phytohormones are induced.

Results in signal transduction that triggers metabolic reprogramming towards defense.12/10/2015Sarbesh 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 plants stress responses.

ROS might attenuate the oxidative stress caused by abiotic stress.12/10/2015Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

MAPK cascadesMAPK pathways activated by pathogen attack. Mediated by SA/ ABA, and the resulting expression of PR genes induces defense reactions.

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

Transcription Factors and Molecular Responses in Cross-ToleranceSpecific 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.12/10/2015Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

PR genesPR genes are induced on plants 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.12/10/2015Sarbesh D. Dangol, PhD Agricultural Genetic Engineering

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

PR genes upregulation during stresses

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

Cross-signaling

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

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

TranscriptionalRegulation During abiotic stress

Central dogma

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

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

Post-transcriptionalregulation during abiotic stress

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

Post-transcriptional regulation

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

Post-transcriptional regulation during Geminivirus infection

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

Geminivirus tries to antagonize plants stress response

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

Post transcriptional regulation during Agrobacterium infection

Thank you.

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