Redundant and specific roles of individual MIR172 genes in plant development

• Published in: PLoS biology Vol. 19; no. 2; p. e3001044
• Main Authors: Lian, Heng, Wang, Long, Ma, Ning, Zhou, Chuan-Miao, Han, Lin, Zhang, Tian-Qi, Wang, Jia-Wei
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 02.02.2021; Public Library of Science (PLoS)
• Subjects: Analysis; Arabidopsis thaliana; Biology and Life Sciences; Cloning; CRISPR; Deoxyribonucleic acid; DNA; Ethyl methanesulfonate; Fast neutrons; Flowers & plants; Gene expression; Gene loci; Genes; Genetic aspects; Genetic engineering; Genomes; Genotype & phenotype; Identification and classification; Irradiation; Measurement; MicroRNA; MicroRNAs; Mutagenesis; Mutants; Mutation; Neutron irradiation; Physiological aspects; Plants (botany); Plants, Flowering of; Research and Analysis Methods; Roles; T-DNA; Transcription factors; Transgenic plants; China
• ISSN: 1545-7885; 1544-9173; 1545-7885
• DOI: 10.1371/journal.pbio.3001044

Evolutionarily conserved microRNAs (miRNAs) usually have high copy numbers in the genome. The redundant and specific roles of each member of a multimember miRNA gene family are poorly understood. Previous studies have shown that the miR156-SPL-miR172 axis constitutes a signaling cascade in regulating plant developmental transitions. Here, we report the feasibility and utility of CRISPR-Cas9 technology to investigate the functions of all 5 MIR172 family members in Arabidopsis. We show that an Arabidopsis plant devoid of miR172 is viable, although it displays pleiotropic morphological defects. MIR172 family members exhibit distinct expression pattern and exert functional specificity in regulating meristem size, trichome initiation, stem elongation, shoot branching, and floral competence. In particular, we find that the miR156-SPL-miR172 cascade is bifurcated into specific flowering responses by matching pairs of coexpressed SPL and MIR172 genes in different tissues. Our results thus highlight the spatiotemporal changes in gene expression that underlie evolutionary novelties of a miRNA gene family in nature. The expansion of MIR172 genes in the Arabidopsis genome provides molecular substrates for the integration of diverse floral inductive cues, which ensures that plants flower at the optimal time to maximize seed yields.