Citrulline metabolism in plants

Area of Science:

• Plant biochemistry
• Amino acid metabolism
• Agricultural science

Background:

• Citrulline is a non-proteinogenic amino acid found across diverse organisms.
• Research has primarily focused on citrulline in *Arabidopsis thaliana* and *Cucurbitaceae*, especially watermelon.
• Watermelon accumulates high levels of citrulline, suggesting economic viability for co-extraction.

Purpose of the Study:

• To review current knowledge on plant citrulline biosynthesis, transport, and catabolism.
• To identify gaps in understanding plant citrulline metabolism and function.
• To explore the potential of watermelon as an industrial source of citrulline.

Main Methods:

• Literature review of plant citrulline research.
• Analysis of citrulline biosynthesis pathways.
• Discussion of transport mechanisms and catabolic processes.

Main Results:

• Overview of established citrulline metabolic pathways in plants.
• Identification of areas needing further research, including enzyme identification and spatial resolution of transport.
• Discussion of proposed roles in nitrogen scavenging and as a compatible solute.

Conclusions:

• Significant gaps remain in understanding citrulline metabolism and function in plants.
• Further research is needed to identify novel enzymes and elucidate transport mechanisms.
• Watermelon presents a promising source for industrial citrulline production through co-extraction.