|LEE, CHRISTOPHER - Pennsylvania State University
|DAZEN, KEVIN - Pennsylvania State University
|Delhom, Christopher - Chris
|Rodgers Iii, James
|French, Alfred - Al
|KIM, SEONG - Pennsylvania State University
Submitted to: Cellulose
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/28/2017
Publication Date: 4/7/2017
Citation: Kim, H.J., Lee, C.M., Dazen, K., Delhom, C.D., Liu, Y., Rodgers III, J.E., French, A.D., Kim, S.H. 2017. Comparative physical and chemical analyses of cotton fibers from two near isogenic upland lines differing in fiber wall thickness. Cellulose. 24:2385-2401.
Interpretive Summary: Cotton fiber wall thickness is an important property of determining values of cotton fibers. An immature fiber (im) mutant with thin fiber wall and its near isogenic wild type, Texas Marker-1 (TM-1) with thick fiber wall provide a unique way of studying structural properties determining the degree of cotton fiber wall thickness. Using both traditional and innovative analytical techniques, we have characterized the physical and chemical properties of developing and developed fibers from TM-1 and im that have been extensively studied for identifying potential molecular mechanisms regulating fiber wall thickness by genetic and genomic approaches. The im fibers were previously thought to suffer from arrested or retarded cellulose biosynthesis during fiber development. Our results showed 1) common developmental stages and similar chemical compositions for the im and TM-1 fibers; 2) the thin cell wall of the im fiber is caused by disruption of cellulose organization in the cell wall. The comprehensive analyses of developing fibers will be useful for bridging the gap between genotypic and phenotypic cotton researches, interpreting gene expression profiles that have been dramatically expanded with recent cutting edged genomic techniques, and providing another way of dissecting functions of candidate genes involved in fiber wall thickness process.
Technical Abstract: The thickness of cotton fiber cell walls is an important property that partially determines the economic value of cotton. To better understand the physical and chemical manifestations of the genetic variations that regulate the degree of fiber wall thickness, we used a comprehensive set of methods to compare fiber properties of the immature fibers (im) mutant that produces thin-walled fibers and its isogenic wild type Texas Marker-1 (TM-1) that is a standard upland cotton variety producing normal fibers with thick-walls. Comprehensive structural analyses showed that im and TM-1fibers shared a common developmental process of cell wall thickening, contrary to the previous report that the phase in the im fiber development might be arrested or retarded. No significant differences were found in cellulose content, crystallinity index, crystal size, matrix polymer composition, ribbon width between the isogenic fibers. In contrast, significant differences were detected in their linear density, cross-section micrographs of fibers from opened bolls, and in the lateral order between their cellulose microfibrils (CMFs). The cellulose mass in a given fiber length was lower and the CMFs were less organized in the im fibers compared with the TM-1 fibers. The presented results imply that the disruption of CMF organization or assembly in the cell walls may be associated with the immature phenotype of the im fibers.