Utilization of nucleoside diphosphate glucoses in developing cotton fibers

Area of Science:

• Plant Biochemistry
• Cellulose Biosynthesis
• Cotton Fiber Development

Background:

• Cotton fibers are a model for primary and secondary cell wall synthesis.
• Understanding the biosynthesis pathways is crucial for improving cotton fiber properties.

Purpose of the Study:

• To investigate the biosynthesis of hot alkali-insoluble products in cotton fibers.
• To differentiate the roles of uridine diphosphate-glucose (UDP-glucose) and guanosine diphosphate-glucose (GDP-glucose) in cotton fiber development.

Main Methods:

• Isolated cotton fibers were harvested at various developmental stages.
• Radioactive labeling with GDP-(14)C-glucose and UDP-(14)C-glucose was used.
• Hot alkali-insoluble products were analyzed, including chromatographic separation.

Main Results:

• GDP-glucose incorporation was high during rapid elongation and primary wall synthesis, forming a cellulose-like product.
• UDP-glucose incorporation was low in young fibers but increased in older fibers, forming chloroform-methanol soluble glucolipids.
• Two presumed glucolipid components increased with fiber age.

Conclusions:

• GDP-glucose is the primary substrate for cellulose biosynthesis during cotton fiber primary wall formation.
• UDP-glucose is involved in the synthesis of glucolipids, with increasing activity in later stages of fiber development.
• These findings elucidate distinct roles for different glucose nucleotide substrates in cotton fiber cell wall biosynthesis.