Blakeslea trispora genes for carotene biosynthesis.

Area of Science:

• Molecular Biology
• Biochemistry
• Mycology

Background:

• Beta-carotene is a vital pigment with significant industrial and nutritional applications.
• Understanding the genetic basis of beta-carotene biosynthesis is crucial for optimizing its production.
• Blakeslea trispora is a known producer of carotenoids, making it a valuable model organism.

Purpose of the Study:

• To clone and characterize the carB and carRA genes responsible for beta-carotene biosynthesis in Blakeslea trispora.
• To investigate the genetic differences between wild-type and overproducing strains of B. trispora.
• To assess the functional utility of B. trispora carB and carRA genes in heterologous systems.

Main Methods:

• Gene cloning and sequencing of carB and carRA from Blakeslea trispora.
• Analysis of gene and protein sequences, including identification of mutations and introns.
• Functional complementation assays using Mucor circinelloides as a heterologous host.

Main Results:

• The carB and carRA genes were successfully cloned and sequenced, revealing their respective sizes and intron-exon structures.
• Specific mutations (S528R in CarB, P143S in CarRA) were identified in the overproducing strain (F-744).
• The cloned B. trispora genes complemented mutations in Mucor circinelloides and led to increased beta-carotene production in transformed strains.

Conclusions:

• The carB and carRA genes are conserved among zygomycetes.
• The identified mutations in the overproducing strain likely contribute to enhanced beta-carotene synthesis.
• These genes represent valuable tools for metabolic engineering to improve carotenoid yields.