Dodder species (Cuscuta spp.) are holoparasites that have extensive material exchange with their host plants through vascular connections. Recent studies on cross-species transfer have provided breakthrough insights, but little is known about the interaction mechanisms of the inter-plant mobile substances in parasitic systems. We sequenced the transcriptomes of dodder growing on soybean hosts to characterize the long non-coding RNA (lncRNA) transfer between the two species, and found that lncRNAs can move in high numbers (365 dodder lncRNAs and 14 soybean lncRNAs) in a bidirectional manner. Reverse transcription-polymerase chain reaction further confirmed that individual lncRNAs were trafficked in the dodder–soybean parasitic system. To reveal the potential functions of mobile transcripts, the Gene Ontology terms of mobile lncRNA target genes were predicted, and mobile dodder target genes were found to be mainly enriched in “metabolic process”, “catalytic activity”, “signaling”, and “response to stimulus” categories, whereas mobile soybean target genes were enriched in organelle-related categories, indicating that specific mobile lncRNAs may be important in regulating dodder parasitism. Our findings reveal that lncRNAs are transferred between dodder and its host soybean plants, which may act as critical regulators to coordinate the host–dodder interaction at the whole parasitic level.

Budgerigar fledgling disease virus (BFDV) represents the first non-mammalian member of the polyomavirus genus and possesses uncommon structural and biological properties. Recombinant baculoviruses were constructed to express BFDV small t antigen, large T antigens, as well as a large T deletion mutant Td and β-galactosidase-Td fusion proteins to high levels in infected insect cells. A recombinant virus containing a genomic copy of the BFDV early region was used for small t antigen expression, and corresponding introndeleted cDNAs for production of large T antigen derivatives. Recombinant T as well as authentic T antigen proteins from infected chicken embryo fibroblasts were purified using both immunoaffinity and DNA affinity column chromatography. We present evidence that the large T antigen interacts specifically with DNA sequences present in the non-coding region of BFDV; by indirect DNA immunoprecipitation mapping and DNase I footprinting, four regions including 12 DNA-binding sites have been determined that cover most of the BFDV non-coding region. The T antigen binding pattern observed suggests a protein-DNA interaction system considerably different from those of simian virus 40 and other polyomaviruses.

As an important source of protein for livestock and human consumption, Vicia sativa is cultivated worldwide, but its seed production is hampered at high altitudes because of the short frost-free period. Flowering represents the transition from a vegetative to a reproductive period, and early flowering benefits plant seed production at high altitudes. However, the molecular mechanisms of flowering regulation in V. sativa remain elusive. In the present study, two V. sativa accessions with different flowering characteristics were used: Lan3 (early-flowering) was cultivated by our laboratory, and 503 (late-flowering) was selected from 222 V. sativa accessions after three years of field experiments. The shoot samples (shoot tip length = 10 cm) of these two accessions were collected 63, 70, and 77 days after sowing, and the molecular regulatory mechanism of the flowering process was identified by integrative analyses of the transcriptomes and metabolomes. Kyoto Encyclopedia of Genes and Genomes enrichment showed that the synthesis and signal transduction of plant hormone pathways were the most enriched pathways in 4274 differentially expressed genes (DEGs) and in 259 differential metabolites between Lan3 and 503. Moreover, the contents of three metabolites related to salicylic acid biosynthesis and the transcription levels of two DEGs related to salicylic acid signal transduction in Lan3 were higher than those in 503. Further verification in various accessions indicated that salicylic acid metabolism may be involved in the flowering regulation process of V. sativa. These findings provide valuable information for understanding the flowering mechanism and for promoting breeding research in V. sativa.

The common vetch (Vicia sativa L.) seed is an ideal plant-based protein food for humans, but its edible value is mainly limited by the presence of cyanogenic glycosides that hydrolyze to produce toxic hydrogen cyanide (HCN), and the genes that regulate HCN synthesis in common vetch are unknown. In this study, seeds from common vetch at 5, 10, 15, 20, 25, 30, and 35 days after anthesis were sampled, and the seven stages were further divided into five developmental stages, S1, S2, S3, S4, and S5, based on morphological and transcriptome analyses. A total of 16,403 differentially expressed genes were identified in the five developmental stages. The HCN contents of seeds in these five stages were determined by alkaline titration, and weighted gene coexpression network analysis was used to explain the molecular regulatory mechanism of HCN synthesis in common vetch seeds. Eighteen key regulatory genes for HCN synthesis were identified, including the VsGT2, VsGT17 and CYP71A genes, as well as the VsGT1 gene family. VsGT1, VsGT2, VsGT17 and CYP71A jointly promoted HCN synthesis, from 5 to 25 days after anthesis, with VsGT1-1, VsGT1-4, VsGT1-11 and VsGT1-14 playing major roles. The HCN synthesis was mainly regulated by VsGT1, from 25 to 35 days after anthesis. As the expression level of VsGT1 decreased, the HCN content no longer increased. In-depth elucidation of seed HCN synthesis lays the foundations for breeding common vetch with low HCN content.

Elephant grass (Cenchrus purpureus) is an important forage crop hindered by high lignin content. Although MYB transcription factors (TFs) regulate lignin biosynthesis, their roles in elephant grass remain unclear. In this study, we identified 247 CpMYB TFs through whole-genome bioinformatic analysis of elephant grass and classified them into 23 phylogenetic subgroups. Among them, 233 were mapped to 14 chromosomes, and 14 to unanchored contigs. Gene structure, conserved motifs, and domain analyses revealed subgroup-specific conservation and CpMYB proteins dominated by random coils and α-helices. Gene duplication and selection pressure analyses indicated that segmental duplication predominantly contributed to family expansion. Transcriptome analysis identified 48 CpMYB genes differentially expressed in internodes at least one of three developmental stages, with promoters containing various growth-, phytohormone-, and stress-related cis-elements. Additionally, nine CpMYB genes were consistently differentially expressed across all three stages, and predicted protein–DNA interaction suggested that four of them (CpMYB094, CpMYB131, CpMYB145, and CpMYB148) potentially regulate key lignin biosynthetic genes, including 4-coumarate:CoA ligase 1 (4CL1), hydroxycinnamoyl transferase (HCT), caffeoyl-CoA O-methyltransferase 1/7 (CCoAOMT1/7), and reduced epidermal fluorescence 3 (REF3). However, their regulatory functions require further experimental validation. Overall, this study characterizes the CpMYB family in elephant grass and highlights their potential roles in lignin biosynthesis.