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.

The excessively concentrated ripening period of mulberries causes seasonal surplus. Fruit mulberry (Morus spp.) exhibits the unique trait of “simultaneous flowering and leaf flushing”, rendering budburst timing closely correlated with fruit ripening time. Thus, deciphering the molecular mechanism underlying winter bud dormancy maintenance in fruit mulberry is urgently needed. Herein, an F₁ hybrid population comprising 337 individuals, derived from Morus wittiorum (♀) and ‘322’ (♂), was utilized as research material. Through Bulked Segregant Analysis Sequencing (BSA-Seq), we successfully mapped a dormancy-associated QTL interval designated as LB (Late Burst), spanning 9,990,001–11,990,000 bp on Chromosome 13. Integrating Weighted Gene Co-expression Network Analysis (WGCNA) results, MaSVP was identified as a candidate gene within this interval. Virus-induced gene silencing (VIGS) of MaSVP in winter buds of Morus wittiorum significantly accelerated budburst compared to the control, demonstrating that MaSVP represses winter bud dormancy release and plays a crucial role in regulating dormancy maintenance in fruit mulberry. Dynamic expression profiling of dormancy-related genes revealed that the transcript levels of MaSVP, MaSAPK3, MaCASL2, and MaPYR8 were significantly downregulated (Tukey’s test, p < 0.05) as budburst approached, whereas those of MaFT and MaGA20ox1-D were significantly upregulated (Tukey’s test, p < 0.05). These results indicate that winter bud dormancy maintenance in Morus wittiorum is associated with abscisic acid (ABA) and gibberellin (GA) metabolism. Collectively, this study provides critical insights into the biological basis of winter bud dormancy maintenance in fruit mulberry and offers valuable genetic resources for breeding late-maturing cultivars.

Maintenance of winter bud dormancy is a critical agronomic trait determining the fruit ripening period in mulberry (Morus spp.); however, the underlying molecular regulatory mechanisms remain largely elusive. In this study, we utilized an F1 segregating population derived from a cross between the late-budding species Morus wittiorum and the early-budding cultivar '322'. By integrating bulked segregant analysis sequencing (BSA-Seq) with RNA-Seq, we identified a dormancy-associated quantitative trait locus (QTL) interval (LB, 9.99-11.99 Mb) on chromosome 13 and pinpointed MaBGA (a β-glucosidase gene) as a candidate gene. Functional characterization via virus-induced gene silencing (VIGS) demonstrated that MaSVP acts as a repressor of winter bud sprouting, whereas MaBGA facilitates dormancy release. Yeast one-hybrid, dual-luciferase reporter, and electrophoretic mobility shift assays (EMSA) further confirmed that MaSVP directly binds to the MaBGA promoter to repress its transcription. Consistently, MaBGA expression was significantly upregulated during bud sprouting. Here, we unveil a novel MaSVP-MaBGA regulatory module. Distinct from the classical model where SVP/DAM proteins regulate dormancy indirectly via hormone homeostasis, this module maintains winter bud dormancy through the direct molecular interaction between a transcription factor and a β-glucosidase gene, thereby expanding the molecular regulatory network of bud dormancy in perennial plants. These findings not only provide fresh insights into the dormancy mechanisms of mulberry but also offer critical genetic resources and theoretical foundations for the molecular breeding of early- and late-ripening varieties.