Phytochrome the given homework in your.pptx

It is a great news from the given homework in your 4 line book and send the group of the day of the day of the day of the day of the day of the day of the day of the day of the day of the day of the day

1. BHARATHI COLLEGE PG AND RC BHARATHINAGARA PAPER: Biochemistry and plant physiology. . TOPIC: Biochemical properties of Phytochrome. 2023-2024 Presented by: Nisarga K S II Msc Botany IIIrd sem Reg no: P21UE23S0280004 Bharathi College, PG & RC Bharathinagar . Presented to: Srinidhi.M Assit . Professor Department of Botany Bharathi College, PG & RC Bharathinagar .

2. CONTENT: Introduction. Structure. Characteristics Biochemical properties. Conclusion. Reference.

3. Phytochromes are a class of photoreceptor proteins found in plants, fungi, and bacteria, which are primarily responsible for detecting light and regulating various aspects of plant growth and development. They help plants respond to the light environment, enabling processes like seed germination, stem elongation, flowering, and shade avoidance. There are five major types of phytochromes , known as phytochrome A through phytochrome E. Phytochromes primarily detect red and far-red light, which are important wavelengths for plant growth. INTRODUCTION

4. THE BIOCHEMICAL PROPERTIES OF PHYTOCHROME ARE AS FOLLOWS: 1. Light Sensitivity and Conformational Changes: - Phytochrome exists in two interconvertible forms: * Pr (red-light-absorbing form) and * Pfr (far-red-light-absorbing form). - * Pr absorbs red light (around 660 nm) and is converted to * Pfr . - * Pfr absorbs far-red light (around 730 nm) and reverts to *Pr. - The interconversion between * Pr and * Pfr forms is central to phytochrome's role in light signal transduction.

5. 2. Chromophore : - The chromophore of phytochrome is a bilin (a linear tetrapyrrole ) structure, usually phytochromobilin in plants. - The bilin chromophore absorbs light and undergoes a conformational change, which triggers downstream signaling events in the plant.

6. 3. Structural Domains: - Phytochromes have two main domains: *N-terminal domain: This contains the chromophore binding region and the light-sensing domain. It interacts with light, causing the conformational changes between Pr and Pfr *C-terminal domain: This is involved in signal transduction. Upon light-induced conformational change, this domain interacts with other proteins to initiate gene expression and other physiological responses.

7. 4. Signal Transduction: - After the conversion from Pr to Pfr , the phytochrome undergoes a conformational change that leads to the activation of downstream signaling pathways. - In many plants, the signaling cascade is mediated by phytochrome -interacting factors (PIFs), hich are transcription factors that regulate light-responsive genes. - In some cases, the Pfr form of phytochrome can interact with kinases or other proteins to trigger changes in gene expression.

8. 5. Regulation of Gene Expression: - Phytochromes influence gene expression through their ability to interact with transcription factors such as PIFs. This affects processes like: *Germination of seeds *Flowering in response to photoperiods * Plant growth and development (e.g., shade avoidance response).

9. Phytochromes are vital photoreceptor proteins that play a crucial role in regulating plant growth and development by detecting light. These proteins enable plants to sense and respond to changes in light quality, quantity, and direction, thus influencing various processes like seed germination, stem elongation, flowering, and chloroplast movement. Phytochromes work by switching between two interconvertible forms ( Pr and Pfr ) in response to red and far-red light. This ability to adapt to environmental light conditions helps plants optimize their growth for survival. Understanding phytochrome mechanisms not only enhances our knowledge of plant biology but also has practical applications in agriculture and horticulture for improving crop yields and controlling growth patterns. CONCLUSION

10. Yang, X., & Li, L. (2019). "Phytochrome signaling and regulation of plant growth and development." Plant Molecular Biology. Smith, H. (2000). " Phytochromes and light signal perception by plants." Trends in Plant Science. w ww.Slideshare.Com REFERENCE