Unveiling the OsPIF15 and OsPIF16 regulatory network underlying rice coleoptile growth

• Autor(a) principal: Franco de Matos e Silva Neves, Sofia
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/163585
• topic: phytochrome-interacting factor (PIF); coleoptile elongation; skotomorphogenesis; light signaling

"Light is a key environmental cue, influencing most stages of plant development and growth, including seedling establishment. Upon seedling emergence, red/far-red light-absorbing phytochromes (phys) are light-activated and translocated into the nucleus, where they interact with phytochrome-interacting factors [PIFs; bHLH transcription factors (TFs)], promoting PIF degradation or inhibiting PIFs from binding to their DNA targets, and shifting the seedling’s developmental program from skoto- to photomorphogenesis. In rice, three phytochromes (OsphyA-C) and seven PIFs (OsPIF11-16, OsPIF8) have been identified, but this regulatory network remains fairly unknown. When CRISPR/Cas9 knockout single and double ospif mutants were grown under dark, ospif15 and ospif16 seedlings developed shorter coleoptiles than the wild-type (WT), but the difference was greater in the ospif15 ospif16 lines. Under white, red and far-red light, there were no significant differences in coleoptile length between mutants and the WT. Thus, OsPIF15 and OsPIF16 were identified as positive regulators of skotomorphogenesis. To further uncover these TF’s functional roles in light-dependent regulation of coleoptile growth, we investigated their interactions with OsphyA-C. Both OsPIFs interacted with OsphyB, but only OsPIF15 interacted with OsphyA. As members of the bHLH TF family, their ability to homo- and heterodimerize was tested as well, and preliminary results showed that both OsPIF15 and OsPIF16 form homo- and hetero-dimers. OsphyB-mediated degradation of OsPIF15 by light has already been described. We analyzed OsPIF16 stability under light in WT and phyB-1 mutants and showed that OsPIF16 degradation by light is OsphyB-dependent(...)"