Question

hy4 gene related to photomorphogensis was later named as

• A. cry1 gene
• B. cry3 gene
• C. cry9 gene
• D. cry7 gene

Hint:

Cryptochromes (cry1, cry2) are the primary photoreceptors regulating blue-light-induced photomorphogenesis, such as hypocotyl elongation inhibition and cotyledon expansion.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Photomorphogenesis is the growth and development of plants in response to light signals.
This process is mediated by photoreceptors, including phytochromes (red/far-red light) and cryptochromes (blue/UV-A light).

Step 3: Detailed Explanation:
In Arabidopsis thaliana, the hy4 mutant was originally identified due to its elongated hypocotyl phenotype under blue light conditions.
Molecular cloning of the HY4 gene revealed that it encodes a blue light receptor protein containing flavin and pterin chromophores.
Because of its role as a blue light receptor homologous to microbial DNA photolyases, this gene and its protein product were subsequently named cryptochrome 1 (cry1).

Step 4: Final Answer:
The hy4 gene was later renamed as the cry1 gene, which corresponds to option (A).