Light triggers the miRNA-biogenetic inconsistency for de-etiolated seedling survivability in Arabidopsis thaliana

The shift of dark-grown seedlings into light causes enormous transcriptome changes followed by a dramatic developmental transition. Here, we show that miRNA biogenesis also undergoes regulatory changes during de-etiolation. Etiolated seedlings maintain low levels of primary-miRNAs (pri-miRNAs) and miRNA processing core proteins, such as Dicer-like 1 (DCL1), SERRATE (SE) and HYPONASTIC LEAVES 1 (HYL1), whereas during de-etiolation, both pri-miRNAs and the processing components accumulated to high levels. However, most miRNA levels did not notably increase in response to light. To reconcile this inconsistency, we demonstrate that an unknown suppressor decreases miRNA-processing activity and light-induced SMALL RNA DEGRADING NUCLEASE 1 (SDN1) shortens the half-life of several miRNAs in de-etiolated seedlings. Taken together, we suggest a novel mechanism, miRNA-biogenetic inconsistency, which accounts for the intricacy of miRNA biogenesis during de-etiolation. This mechanism is essential for the survival of de-etiolated seedlings after long-term skotomorphogenesis and their optimal adaptation to ever-changing light conditions. Fil: Choi, Suk Won. Yonsei University; Corea del Sur Fil: Ryu, Moon Young. Yonsei University; Corea del Sur Fil: Viczián, András. Hungarian Academy Of Sciences; Hungría Fil: Jung, Hyun Ju. Yonsei University; Corea del Sur Fil: Kim, Gu Min. Yonsei University; Corea del Sur Fil: Arce, Agustín Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentina Fil: Achkar, Natalia Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentina Fil: Manavella, Pablo Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentina Fil: Dolde, Ulla. Laboratoire de Recherche En Sciences Végétales; Francia Fil: Wenkel, Stephan. University Of Copenhagen; Dinamarca Fil: Molnár, Attila. University of Edinburgh; Reino Unido Fil: Nagy, Ferenc. Hungarian Academy Of Sciences; Hungría Fil: Cho, Seok Keun. Yonsei University; Corea del Sur Fil: Yang, Seong Wook. Yonsei University; Corea del Sur