摘要：SummaryCotton fiber is an excellent model for studying plant cell elongation and cell wall biogenesis as well because they are highly polarized and use conserved polarized diffuse growth mechanism. Fiber strength is an important trait among cotton fiber qualities due to ongoing changes in spinning technology. However, the molecular mechanism of fiber strength forming is obscure. Through map-based cloning, we identified the fiber strength geneGhUBX. Increasing its expression, the fiber strength of the transgenic cotton was significantly enhanced compared to the receptor W0 and the helices number of the transgenic fiber was remarkably increased. Additionally, we proved that GhUBX regulates the fiber helical growth by degrading the GhSPL1 via the ubiquitin 26S–proteasome pathway. Taken together, we revealed the internal relationship between fiber helices and fiber stronger. It will be useful for improving the fiber quality in cotton breeding and illustrating the molecular mechanism for plant twisted growth.Graphical abstractDisplay OmittedHighlights•Isolation of the first fiber strength gene GhUBX using map-based cloning strategy•Verification of the function of GhUBX experimentally in transgenic cotton•Link helices to the cotton fiber strength, that more helices make fiber stronger•An ubiquitin–proteasome system regulating the development of cotton fiberMolecular biology; Plant biology; Genomics ;
