Molecular mechanisms of miR172a and its target gene LbrTOE3 regulating maturation in Lilium

MAIN CONCLUSION

Lbr-miR172a could promote the growth phase transition and shorten maturation in Lilium, while LbrTOE3 inhibited this process and prolonged the growth period. Lilium is an ornamental flower with high economic value for both food and medicinal purposes. However, under natural conditions, Lilium bulbs take a long time and cost more to grow to commercial size. This research was conducted to shorten the maturation time by subjecting Lilium bulbs to alternating temperature treatment. To explore the molecular mechanism of the vegetative phase change (VPC) in Lilium after variable temperature treatment, the key module miR172a-TOE3 was selected based on a combined omics analysis. Gene cloning and transgene functional validation showed that overexpression of Lbr-mir172a promoted a phase change, while overexpression of LbrTOE3 inhibited this process. Subcellular localization and transcriptional activation assays indicated that LbrTOE3 was predominantly localized in the nucleus and showed transcriptional activity. In situ hybridization showed that LbrTOE3 expression was significantly downregulated after alternating temperature treatment. This study elucidates the molecular mechanisms of the phase transition of Lilium and provides a scientific basis for the phase transition in other plants.

Regulatory Mechanisms of ArAux/IAA13 and ArAux/IAA16 in the Rooting Process of Acer rubrum

Acer rubrum is difficult to root during cutting propagation. Auxin/indole-acetic acids (Aux/IAA) proteins, which are encoded by the early response genes of auxin, are transcriptional repressors that play important roles in auxin-mediated root growth and development. In this study, ArAux/IAA13 and ArAux/IAA16, which were significantly differentially expressed after 300 mg/L indole butyric acid treatment, were cloned. Heatmap analysis revealed that they might be associated with the process of adventitious root (AR) growth and development mediated by auxin. Subcellular localization analysis showed that they performed their function in the nucleus. Bimolecular fluorescence complementation assays revealed the interactions between them and two auxin response factor (ARF) proteins, ArARF10 and ArARF18, confirming their relevance to AR growth and development. Overexpression of transgenic plants confirmed that the overexpression of ArAux/IAA13 and ArAux/IAA16 inhibited AR development. These results help elucidate the mechanisms of auxin-mediated AR growth and development during the propagation of A. rubrum and provide a molecular basis for the rooting of cuttings.