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Fibre elongation requires normal redox homeostasis modulated by cytosolic ascorbate peroxidase in cotton (Gossypium hirsutum)

Update Time: 2016-04-20 20:49:49Click:5480 times
Kai Guo, Xueqiong Du, Lili Tu*, Wenxin Tang, Pengcheng Wang, Maojun Wang, Zhen Liu and Xianlong Zhang.2016.Journal of Experimental Botany


High-quality cotton fibre equates to a more comfortable textile. Fibre length is an important index of fibre quality. Hydrogen peroxide (H2O2) acts as a signalling molecule in the regulation of fibre elongation. Results fromin vitroovule culture suggest that the alteration of fibre cell H2O2levels affects fibredevelopment. Ascorbate peroxidase (APX) is an important reactive oxygen species (ROS) scavenging enzyme, and we found thatGhAPX1AT/DTencoded one member of the previously unrealized group of cytosolic APXs (cAPXs) that were preferentially expressed during the fibre elongationstage. Transgenic cottons with up- and down-regulation ofGhAPX1AT/DT were generated to control fibre endogenous levels of H2O2 Suppression of allcAPX(IAO) resulted in a 3.5-fold increase in H2O2level in fibres and oxidative stress, which significantly suppressed fibre elongation. The fibrelength of transgenic lines with over-expression or specific down-regulation ofGhAPX1AT/DT did not show any obvious change. However, the fibres in the over-expression lines exhibited higher tolerance to oxidative stress. Differentially expressed genes (DEGs) in fibres at 10 days post-anthesis (DPA) of IAO lines identified by RNA-seq were related to redox homeostasis, signalling pathways, stress responses and cell wall synthesis, and the DEGs that were up-regulated in IAO lines were also up-regulated in the 10 DPA and 20 DPA fibres of wild cotton compared with domesticated cotton. These results suggest that optimal H2O2levels and redox state regulated by cytosolic APX are key mechanisms regulating fibre elongation, and dysregulation of the increase in H2O2induces oxidative stress and results in shorter fibres by initiating secondary cell wall-related gene expression.

pii: erw146. IF=5.526

PMID: 27091877.