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Updated: Sep 29, 2025

Lignin Down-regulation of Zea mays via dsRNAi and Klason Lignin Analysis
Published on: July 23, 2014
Ethylene regulates miRNA-mediated lignin biosynthesis and leaf serration in Arabidopsis thaliana
Subhash Reddy Gaddam1, Chitra Bhatia2, Himanshi Gautam2
1CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research (CSIR-NBRI), Rana Pratap Marg, Lucknow, 226001, India; Department of Botany, University of Lucknow, Lucknow, 226007, India.
Abstract:
microRNAs (miRNAs) regulate target gene expression by pairing to target mRNAs, leading to mRNA degradation or translation inhibition. Out of several miRNAs in Arabidopsis, miR397b and miR857 regulate secondary growth by modulating lignin polymerization and deposition in secondary xylem cells by targeting laccases. Interestingly, the phytohormone ethylene is also suggested to have a role in lignin biosynthesis in tension wood formation. Despite this information, it is not known whether ethylene has any role in controlling secondary growth via miRNAs-mediated pathways. In this study, we elucidate that ethylene acts upstream to the miR397b/miR857-laccases module and negatively regulates lignin biosynthesis by directly activating the expression of both the miRNAs. The binding of EIN3 to the promoter of miR397b is further validated by yeast one-hybrid assay. In addition to its role in lignification, ethylene also regulates leaf serration by directly regulating the expression of NAC transcription factors, like CUP-SHAPED COTYLEDON2 (CUC2) and CUC3. Together, our study suggests a novel mechanism involving ethylene and miRNAs in lignin biosynthesis and leaf serration in Arabidopsis thaliana.
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