Red And far‐red regulation of filament movement correlates with the expression of phytochrome and FHY1 genes in Spirogyra varians (Zygnematales, Streptophyta)¹

Spirogyra filaments show unique photomovement that differs in response to blue, red, and far-red light. Phototropins involved in the blue-light movement have been characterized together with downstream signaling components, but the photoreceptors and mechanical effectors of red- and far-red light movement are not yet characterized. The filaments of Spirogyra varians slowly bent and aggregated to form a tangled mass in red light. In far-red...