Analysis of differentially expressed genes and fiber development in <italic>Gossypium arboreum</italic> fuzzless mutant

Abstract

<p indent="0mm">Cotton fiber, one of main nature textile and longest single cell, is a good material for researching the cotton fiber development. In this study, fuzz mutant (FZ) and wild-type (<italic>fz</italic>) which belong to diploid <italic>Gossypium arboreum </italic>species were used for unraveling molecular mechanism of fuzz fiber initiation by scanning electron microscopy (SEM), paraffin section and RNA sequencing technology. It was found that any fibers scarcely initiated on the ovule surface of the mutant at 0DPA, compared with that of the wild-type. Only lint fiber cells emerged on the ovule surface of fuzz mutant, while abundant fuzz and lint fiber cells appeared in wild-type at +3DPA stage. The transcriptome analysis of FZ and<italic> fz</italic> across the four fiber development stages (0DPA, +3DPA, +5DPA, and +8DPA) indicated that the number of differentially expressed gene was 3780. There were litter differentially expressed genes at 0DPA in FZ and <italic>fz</italic>. In the proceed of ovule development, the number of differentially expressed genes was increased gradually. The KEGG enriched pathway analysis illustrated that these differentially expressed genes were involved in cutin, suberine and wax biosynthesis, phenylalanine metabolism pathways and plant hormone signal transduction pathways. The analysis of co-expressed gene trend lines indicated that the up-regulated genes in mutant at +3DPA were all involved in metal ion binding, MAPK cascade, oxidoreductase activity and transcription regulation, resulting in failed fuzz fiber cells initiation in mutant. These findings elaborated a dynamic variation about fuzz fiber initiation in diploid <italic>G. arboreum</italic>, which provides a reference for further research in the cotton fiber development.