Processing bodies regulate the time for translation of selected mRNAs in Arabidopsis: from skotomorphogenesis to photomorphogenesis

• Main Authors: Geng-Jen Jang, 張耿禎
• Other Authors: Shu-Hsing Wu
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/48yvu3

博士 === 國立臺灣大學 === 植物科學研究所 === 107 === Germinated plant seeds buried in soil undergo skotomorphogenic development before emergence to reach the light environment. Young seedlings transitioning from dark to light undergo photomorphogenic development. During photomorphogenesis, light alters the transcriptome and enhances the translation of thousands of mRNAs during the dark-to-light transition in Arabidopsis young seedlings. About 1,500 of these mRNAs have comparable abundance before and after light treatment, which implies widespread translational repression in dark-grown seedlings. Processing bodies (p-bodies), the cytoplasmic granules found in diverse organisms, can balance the storage, degradation and translation of mRNAs. However, the function of p-bodies in translation control remains largely unknown in plants. Here I found that an Arabidopsis mutant defective in p-body formation (Decapping 5; dcp5-1) showed reduced fitness under both dark and light conditions. Comparative transcriptome and translatome analyses of wild-type and dcp5-1 seedlings revealed that p-bodies can attenuate the premature translation of specific mRNAs in the dark, including those encoding enzymes for protochlorophyllide synthesis and PIN-LIKES3 for auxin-dependent apical hook opening. When the seedlings protrude from soil, light perception by photoreceptors triggers a reduced accumulation of p-bodies to release the translationally stalled mRNAs for active translation of mRNAs encoding proteins needed for photomorphogenesis. Results obtained will provide mechanistic insights on p-bodies in translation control for proper skotomorphogenesis and timely photomorphogenesis in seedlings.