Transcriptome analysis reveals critical genes and key pathways for early cotton fiber elongation in Ligon lintless-1 mutant

Fiber length is a key determinant of cotton yield and quality. Using a monogenic dominant cotton mutant Ligon lintless-1 with extremely short fibers, we employed microarray technology and quantitative real time PCR to compare transcriptomes of Li1 and the normal wild-type TM-1, the results showed that only a few genes differentially expressed in 0 days postanthesis (DPA) ovules and 3 DPA fibers, whereas 577 transcripts differentially expressed in 6 DPA fibers. 6 DPA is probably a key phase determining fiber elongation. Gene ontology analyses showed such processes as response to stimulus, signal transduction, and lipid metabolism were readjusted by the mutant gene. Pathway studio analysis indicated that auxin signaling and sugar signaling pathways play major roles in modulation of early fiber elongation. This work provides new insight into the mechanisms of fiber development, and offers novel genes as potential objects for genetic manipulation to achieve improvement of fiber properties.

► Fiber morphological change in Li1 occurred on 8 days postanthesis (DPA).
► Profound changes in the transcriptome of Li1 fibers were detected on 6 DPA.
► 6 DPA is probably the critical elongation stage determining cotton fiber length.
► Auxin signal pathway is largely readjusted in Li1 mutant fibers.
► Sugar signaling and cytoskeleton rearrangement are essential for fiber elongation.