Multi-Omics Analysis of Pigmentation Related to Proanthocyanidin Biosynthesis in Brown Cotton (Gossypium hirsutum L.)

Authors: Hinchliffe, Doug; Naoumkina, Marina; Thyssen, Gregory; Nam, Sunghyun; Chang, Sechin; McCarty, Jack; Jenkins, Johnie

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/22/2024
Publication Date: 3/13/2024
Citation: Hinchliffe, D.J., Naoumkina, M., Thyssen, G.N., Nam, S., Chang, S., Mccarty, J.C., Jenkins, J.N. 2024. Multi-Omics Analysis of Pigmentation Related to Proanthocyanidin Biosynthesis in Brown Cotton (Gossypium hirsutum L.). Frontiers in Plant Science. 15: 1372232. https://doi.org/10.3389/fpls.2024.1372232.
DOI: https://doi.org/10.3389/fpls.2024.1372232

Interpretive Summary: Environmentally friendly fibers of naturally-colored brown cotton (NBC) varieties are most commonly used for fabrics. Due to pigments, clothes from NBC fibers resist fading colors during laundry and protect the skin from ultraviolet radiation. Fibers of some NBC varieties exhibited flame retardant (FR) properties that can offer an eco-friendly alternative to synthetic FR additives in textiles. We previously identified the causative mutation resulting in color and FR of Lc1 brown cotton fiber, however, the exact metabolites involved in the FR phenotype remain unknown. To gain further insights into the biosynthesis of pigments and its association with FR in brown fibers, we conducted comparative metabolites profiling analysis of developing cotton fibers between the brown and white cotton near-isogenic lines (NILs), genetically different only in the Lc1 locus. This study found significant changes in thousands of metabolites accumulated in brown and white developing and mature fibers with gallocatechin and catechin appearing to be the main constituents of proanthocyanindin precursors in developing fibers.

Technical Abstract: Naturally-colored brown cotton (NBC) fiber is an environmentally friendly raw source of fiber for textile applications. The fiber of some NBC cultivars exhibits flame-retardant properties, which can be used in textiles that require flame resistance. Proanthocyanidins or their derivatives are responsible for the brown pigment in NBC; however, how flame retardancy is related to pigmentation in NBC is poorly understood. To gain insight into brown pigment biosynthesis, we conducted comparative metabolites profiling analysis of developing cotton fibers between the brown (MC-BL) and white (MC-WL) cotton near-isogenic lines (NILs), genetically different only in the Lc1 locus. In this study, UHPLC-Q-Exactive Orbitrap mass spectrometry was used for the detection of metabolites in developing fibers of BL and WL at 8, 12, 16, 20, 24, 36, and 40 days post anthesis (DPA), and mature fibers. We found 5836 (ESI MS positive mode) and 4541 (ESI MS negative mode) metabolites significantly different accumulated between BL and WL. Among them, 142 were known non-redundant metabolites, including organic acids, amino acids, and derivatives of the phenylpropanoid pathway. Organic acids of the citric acid cycle were induced, while most of the detected amino acids were reduced in the MC-BL line. Both cis- and trans-stereoisomers of flavan-3-ols were detected in developing MC-WL and MC-BL fibers; however, the gallocatechin and catechin accumulated multiple times higher. GC-MS analysis of fatty acids determined that palmitic acid long-chain alcohols were the main constituents of waxes of mature fibers. Energy-dispersive X-ray spectroscopy (EDS) analysis of mature fibers revealed that potassium accumulated three times greater in MC-BL than in MC-WL mature fibers. This study provides novel insights into the biosynthesis of pigments and its association with flame retardancy in NBC fibers.