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The PtoTCP20-miR396d-PtoGRF15 module regulates the secondary vascular development in Populus


Prof. Xinqiang He published a paper in The Plant Communications.

Secondary vascular development is a key biological characteristic of woody plants and the basis of wood formation. Our understanding of the gene expression regulation and dynamic changes of microRNAs (miRNAs) during the secondary vascular development is still limited. Here, we present an integrated analysis of miRNA and mRNA transcriptome, which sampled six phase-specific tissues, namely, the shoot apex, procambium, primary vascular tissue, cambium, secondary phloem and secondary xylem in Populus tomentosa. Several novel regulation modules, including PtoTCP20-miR396d-PtoGRF15 module, were identified during the secondary vascular development in Populus. A series of biochemical and molecular experiments confirmed that PtoTCP20 activated miR396d precursor gene transcription and miR396d targeted PtoGRF15 to down-regulate its expression. 35S:miR396d overexpression plants showed enhanced secondary growth and increased xylem production. Conversely, during the transition from primary to secondary vascular development, the PtoTCP20 down-regulation plant PtoTCP20-SRDXmiR396 down-regulation plant 35S:STTM396 and PtoGRF15 overexpression plant 35S:PtoGRF15 showed delayed secondary growth. Therefore, novel regulation modules were identified by integrated analysis of the miRNA and mRNA transcriptome, and the regulatory role of PtoTCP20-miR396d-PtoGRF15 signaling cascade in the secondary vascular development was validated in Populus, which provide information to support improvements in forest cultivation and wood property.

Original link: https://www.cell.com/plant-communications/fulltext/S2590-3462(22)00341-8.