Zhang, Tian, et al. examine strigolactone signaling in cotton fiber development https://doi.org/10.1093/plcell/koac270
Guanghui Xiao and Yuzhou Zhang
College of Life Sciences, Shaanxi Normal University, Xi’an, China
College of Life Sciences, Northwest A&F University, Shaanxi, Yangling, China
Background: The strigolactone plant hormones regulate plant architecture, including shoot branches and adventurous roots. However, the role of strigolactones in shaping plant cell morphology is still undetermined. Cotton (Gossypium hirsutum) fibers are single-celled trichomes derived from ovule epidermal cells and are excellent models to study plant cell development. Therefore, we used cotton fibers to explore the role of strigolactones in plant cell development and the mechanistic framework involved in this biological process.
Question: How do strigolactones regulate cotton fiber cell growth? What are the regulatory mechanism underlying the strigolactone-mediated fiber cell development?
Findings: Strigolactones enhance cotton fiber cell elongation and cell wall thickness to simultaneously promote length and strength of fiber cells. Furthermore, we identified a cluster of transcription factors that transmit strigolactone signals downstream to the genes related to the biosynthesis of very-long-chain fatty acid and cellulose, the two components essential for the fiber cell elongation and cell wall thickening. Moreover, the accumulation of strigolactones in fiber cells relies on the gibberellin-promoted expression of the strigolactone biosynthesis gene D27, suggesting that the phytohormone gibberellin acts upstream of strigolactones in cotton fiber cell development.
Next steps: For fiber cell development, cell elongation and secondary cell wall thickening generally act antagonistically. Therefore, identifying mechanisms by which the strigolactones promote fiber cell elongation without the penalty of decreasing the secondary cell wall thickness remains an open question for future research.
Yuzhou Zhang, Zailong Tian, Liping Zhu, Bin Jiang, Huiqin Wang, Ruxi Gao, Jiří Friml, Guanghui Xiao (2022) Strigolactones act downstream of gibberellins to regulate fiber cell elongation and cell wall thickness in cotton (Gossypium hirsutum). Plant Cell. https://doi.org/10.1093/plcell/koac270