Chloroplast-to-Nucleus Signaling Regulates MicroRNA Biogenesis in Arabidopsis

• Published in: Developmental cell Vol. 48; no. 3; pp. 371 - 382.e4
• Main Authors: Fang, Xiaofeng, Zhao, Gaozhan, Zhang, Su, Li, Yaoxi, Gu, Hanqing, Li, Yan, Zhao, Qiao, Qi, Yijun
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 11.02.2019
• Subjects: Adenosine Diphosphate - metabolism; Arabidopsis - metabolism; Arabidopsis Proteins - metabolism; Cell Nucleus - metabolism; chloroplast; Chloroplasts - metabolism; exoribonuclease; Exoribonucleases - metabolism; Gene Expression Regulation, Plant - genetics; heat tolerance; microRNA; MicroRNAs - metabolism; miRNA; plastid; retrograde signaling; Signal Transduction - physiology; stress response; Stress, Physiological - physiology; tocopherol; heat tolerance; stress response; plastid; retrograde signaling; chloroplast; miRNA; microRNA; tocopherol; exoribonuclease
• ISSN: 1534-5807; 1878-1551
• DOI: 10.1016/j.devcel.2018.11.046

As integral regulators in plant development and stress response, microRNAs (miRNAs) themselves need to be tightly regulated. Here, we show that tocopherols (vitamin E), lipid-soluble antioxidants synthesized from tyrosine in chloroplasts, positively regulate the biogenesis of miRNAs. Tocopherols are required for the accumulation of 3′-phosphoadenosine 5′-phosphate (PAP), a retrograde inhibitor of the nuclear exoribonucleases (XRN), which may protect primary miRNAs from being degraded and promote mature miRNA production. Such regulation is involved in heat-induced accumulation of miR398 and plant acquisition of heat tolerance. Our study reveals a chloroplast-to-nucleus signaling mechanism that favors miRNA biogenesis under heat and possibly other environmental perturbations. [Display omitted] •Tocopherols positively regulate miRNA biogenesis•Tocopherols are required for PAP accumulation•PAP positively regulates miRNA biogenesis•Retrograde regulation of miR398 confers heat tolerance As key regulators of gene expression, miRNAs themselves are subjected to sophisticated regulation. Fang et al. report that chloroplast retrograde signaling involving tocopherols (vitamin E) and PAP, a retrograde inhibitor of the nuclear XRN exonucleases, regulates miRNA biogenesis in Arabidopsis and confers heat tolerance.