The Role of PnTCP2 in the Lobed Leaf Formation of Phoebe neurantha var. lobophylla

Abstract

A lobed leaf is a common trait in plants, but it is very rare in Lauraceae plants, including species of Phoebe. In the study of germplasm resources of Phoebe neurantha, we found lobed leaf variant seedlings, and the variation could be inherited stably. Studying the lobed leaf mechanism of P. neurantha var. lobophylla can offer insight into the leaf development mechanism of woody plants. RNA-seq and small RNA-seq analysis results showed that a total of 8091 differentially expressed genes (DEGs) and 16 differentially expressed miRNAs were identified in P. neurantha var. lobophylla. Considering previous research results, a leaf margin morphological development related miRNA, pne-miRNA319a, was primary identified as a candidate miRNA. Target gene prediction showed that a total of 2070 genes were predicted to be the target genes of differentially expressed miRNAs. GO enrichment analysis of differentially expressed target genes suggested that PnTCP2 is related to lobed leaf formation. The TRV-VIGS gene silencing of PnTCP2 led to lobed leaves in P. neurantha seedlings. The downregulation of PnTCP2 led to lobed leaves. The yeast two-hybrid test and bimolecular fluorescence complementation test confirmed that the PnTCP2 protein interacted with the PnLBD41 protein. Based on the expression analysis of gene-silenced leaves and RNA-seq and small RNA-seq analysis results, pne- miRNA319a and PnLBD41 might also play important roles in this process. In conclusion, PnTCP2 plays an important and vital role in the formation of the lobed leaves of P. neurantha var. lobophylla.