The heterochronic gene Oryza sativa LIKE HETEROCHROMATIN PROTEIN 1 modulates miR156b/c/i/e levels

• Published in: Journal of integrative plant biology Vol. 62; no. 12; pp. 1839 - 1852
• Main Authors: Cui, Yongtao, Cheng, Jingfei, Ruan, Shuang, Qi, Peipei, Liu, Wei, Bian, Hongwu, Ye, Luhuan, Zhang, Yuping, Hu, Jiang, Dong, Guojun, Guo, Longbiao, Zhang, Yijing, Qian, Qian, Hu, Xingming
• Format: Journal Article
• Language: English
• Published: China (Republic : 1949- ) Wiley Subscription Services, Inc 01-12-2020; State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China%National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China%Institute of Genetic and Regenerative Biology, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
• Subjects: Ectopic expression; Epigenetics; Gene expression; Genetic analysis; Heterochromatin; Heterochromatin protein 1; Histone H3; Histones; Loci; Lysine; Maturation; miRNA; Oryza sativa; Phase transitions; Plants (botany); Polycomb group proteins; Proteins; Ribonucleic acid; RNA
• ISSN: 1672-9072; 1744-7909
• DOI: 10.1111/jipb.12991

The juvenile‐to‐adult transition in plants involves changes in vegetative growth and plant architecture; the timing of this transition has important implications for agriculture. The microRNA miR156 regulates this transition and shoot maturation in plants. In Arabidopsis thaliana, deposition of histone H3 trimethylation on lysine 27 (H3K27me3, a repressive mark) at the MIR156A/C loci is regulated by Polycomb Repressive Complex 1 (PRC1) or PRC2, depending on the developmental stage. The levels of miR156 progressively decline during shoot maturation. The amount of H3K27me3 at MIR156A/C loci affects miR156 levels; however, whether this epigenetic regulation is conserved remains unclear. Here, we found that in rice (Oryza sativa), the putative PRC1 subunit LIKE HETEROCHROMATIN PROTEIN 1 (OsLHP1), with the miR156–SQUAMOSA PROMOTER BINDING PROTEIN‐LIKE (SPL) module, affects developmental phase transitions. Loss of OsLHP1 function results in ectopic expression of MIR156B/C/I/E, phenocopy of miR156 overexpression, and reduced H3k27me3 levels at MIR156B/C/I/E. This indicates that OsLHP1 has functionally diverged from Arabidopsis LHP1. Genetic and transcriptome analyses of wild‐type, miR156b/c‐overexpression, and Oslhp1‐2 mutant plants suggest that OsLHP1 acts upstream of miR156 and SPL during the juvenile‐to‐adult transition. Therefore, modifying the OsLHP1–miR156–SPL pathway may enable alteration of the vegetative period and plant architecture.
In this study, we use mutant phenotype observation, analyzing genetic relationship with miR156s by epistasis genetic test, genome‐wide H3K27me3 ChIP‐sequencing, and transcriptome profiling to show that OsLHP1 has diverged in function from its ortholog in Arabidopsis. OsLHP1 mediate miR156b/c/i/e expression to ensure normal vegetative phase transitions in rice.