Working group session:
Functional Genomics
Presentation type:
poster
Authors:
Han, Jie; Tan, Jiafu; Zhang, Xianlong; Tu, Lili
Presenter:
Han, Jie; Tan, Jiafu; Zhang, Xianlong
Correspondent:
Tu, Lili
Abstract:
Cotton fibers, the single-celled trichomes derived from the ovule epidermis, provide the most important natural material for the global textile industry. A number of studies have demonstrated that regulating endogenous hormone levels through transgenic approaches can improve cotton fiber qualities. Phytosulfokine-α (PSK-α) is a novel peptide hormone in plants that is involved in regulating cell proliferation and elongation. However, its potential applications in crop genetic improvement have not been evaluated. In this study, we describe how exogenous PSK-α application promotes cotton fiber cell elongation in vitro. Chlorate, an effective inhibitor of peptide sulfation, suppressed fiber elongation in ovule culture. Exogenously applied PSK-α partly restored the chlorate-induced suppression. A putative PSK gene (GhPSK) was cloned from Gossypium hirsutum. Expression pattern analysis revealed that GhPSK is preferentially expressed in rapidly elongating fiber cells (5-20 DPA). Overexpression of GhPSK in cotton increased the endogenous PSK-α level and promoted cotton fiber cell elongation, resulting in longer and finer fibers. Further results from electrophysiological and physiological analyses suggest that GhPSK affects fiber development through regulation of K+ efflux. Digital Gene Expression (DGE) profile analysis of GhPSK overexpression lines indicates that PSK signaling may regulate the respiratory electron-transport chain and ROS to affect cotton fiber development. These results imply that peptide hormones are involved in cotton fiber growth, and suggest a new strategy for the biotechnological improvement of cotton fiber quality.