Cuscuta campestris fine-tunes gene expression during haustoriogenesis as an adaptation to different hosts.

The Cuscuta genus comprises obligate parasitic plants that have an unusually wide host range. Whether Cuscuta uses different infection strategies for different hosts or whether the infection strategy is mechanistically and enzymatically conserved remains unknown. To address this, we investigated molecular events during the interaction between field dodder (Cuscuta campestris) and two host species of the Solanum genus that are known to react differently to parasitic infection. We found that host gene induction, particularly of cell wall fortifying genes, coincided with a differential induction of genes for cell wall degradation in the parasite in the cultivated tomato (Solanum lycopersicum) but not in a wild relative (Solanum pennellii). This indicates that the parasite can adjust its gene expression in response to its host. This idea was supported by the increased expression of C. campestris genes encoding an endo-ß-1,4-mannanase in response to exposure of the parasite to purified mono- and polysaccharides in a host-independent infection system. Our results suggest multiple key roles of the host cell wall in determining the outcome of an infection attempt.

An RNA-seq transcriptome analysis for investigating the anti-lung cancer activity of medicinal Cuscuta chinensis Lam plant.

Cuscuta chinensis Lam. is a traditional medicinal herb used to treat female sterility and male reproductive system disorders. However, the anti-lung cancer properties of Cuscuta chinensis Lam. and possible molecular mechanisms have yet to be explored. Thus, the study's main purpose was to evaluate in vitro and in vivo anti-lung cancer properties of C. chinensis water extract (CLW) in human lung adenocarcinomas and the underlying molecular mechanism involved. Our results demonstrated that CLW caused a significant inhibition of cell viability and induced G1 cycle arrest in lung cancer cells. Furthermore, RNA-seq transcriptome analysis revealed 602 common genes with a significant expression in A549 and H1650 cells under CLW treatment. Functional enrichment analysis suggested that these common genes regulated by CLW mainly involve lung cancer cell proliferation, metastases and apoptosis processes. In addition, forty-six common genes (> 2-fold change) regulated by CLW in A549 and H1650 cells were selected for further validation. In vitro quantitative real-time PCR results confirmed that twelve genes were up-regulated, and four genes were down-regulated in A549 and H1650 cells. The in vivo experiment demonstrated CLW could significantly decrease tumour volume and tumour weight of mice compared with the control group. Moreover, in vivo quantitative real-time PCR results revealed that C11orf96, FGFBP1, FOSB and NPTX1 genes were up-regulated and EGR1, GBP4 and MAP2K6 genes were down-regulated in tumour tissues compared with the control group. These data strongly suggest that CLW could be developed as an efficacious drug for lung cancer treatment.

Unprecedented organelle genomic variations in morning glories reveal independent evolutionary scenarios of parasitic plants and the diversification of plant mitochondrial complexes.

BACKGROUND: The morning glories (Convolvulaceae) are distributed worldwide and produce economically important crops, medicinal herbs, and ornamentals. Members of this family are diverse in morphological characteristics and trophic modes, including the leafless parasitic Cuscuta (dodders). Organelle genomes were generally used for studying plant phylogeny and genomic variations. Notably, plastomes in parasitic plants always show non-canonical features, such as reduced size and accelerated rates. However, few organelle genomes of this group have been sequenced, hindering our understanding of their evolution, and dodder mitogenome in particular. RESULTS: We assembled 22 new mitogenomes and 12 new plastomes in Convolvulaceae. Alongside previously known ones, we totally analyzed organelle genomes of 23 species in the family. Our sampling includes 16 leafy autotrophic species and 7 leafless parasitic dodders, covering 8 of the 12 tribes. Both the plastid and mitochondrial genomes of these plants have encountered variations that were rarely observed in other angiosperms. All of the plastomes possessed atypical IR boundaries. Besides the gene and IR losses in dodders, some leafy species also showed gene and intron losses, duplications, structural variations, and insertions of foreign DNAs. The phylogeny reconstructed by plastid protein coding sequences confirmed the previous relationship of the tribes. However, the monophyly of 'Merremieae' and the sister group of Cuscuta remained uncertain. The mitogenome was significantly inflated in Cuscuta japonica, which has exceeded over 800 kb and integrated massive DNAs from other species. In other dodders, mitogenomes were maintained in small size, revealing divergent evolutionary strategies. Mutations unique to plants were detected in the mitochondrial gene ccmFc, which has broken into three fragments through gene fission and splicing shift. The unusual changes likely initially happened to the common ancestor of the family and were caused by a foreign insertion from rosids followed by double-strand breaks and imprecise DNA repairs. The coding regions of ccmFc expanded at both sides after the fission, which may have altered the protein structure. CONCLUSIONS: Our family-scale analyses uncovered unusual scenarios for both organelle genomes in Convolvulaceae, especially in parasitic plants. The data provided valuable genetic resources for studying the evolution of Convolvulaceae and plant parasitism.

Detection of the plant parasite Cuscuta reflexa by a tomato cell surface receptor.

Parasitic plants are a constraint on agriculture worldwide. Cuscuta reflexa is a stem holoparasite that infests most dicotyledonous plants. One exception is tomato, which is resistant to C. reflexa We discovered that tomato responds to a small peptide factor occurring in Cuscuta spp. with immune responses typically activated after perception of microbe-associated molecular patterns. We identified the cell surface receptor-like protein CUSCUTA RECEPTOR 1 (CuRe1) as essential for the perception of this parasite-associated molecular pattern. CuRe1 is sufficient to confer responsiveness to the Cuscuta factor and increased resistance to parasitic C. reflexa when heterologously expressed in otherwise susceptible host plants. Our findings reveal that plants recognize parasitic plants in a manner similar to perception of microbial pathogens.

[Authentication of Cuscutae Semen, Raphani Semen and their adulterants by rapid PCR].

To establish an accurate, rapid and efficient method for authenticating Cuscutae Semen and Raphani Semen by using rapid PCR amplification. The samples of Cuscutae Semen, Raphani Semen and their adulterants were collected. The total DNA of the samples has been extracted, and ITS sequence from Cuscutae Semen, Raphani Semen and their adulterants was amplified by PCR and sequenced directionally. These sequences were aligned by using Clustal W. Specific primers were designed and amplified by two-steps PCR amplification method. The rapid PCR methods for authenticating Cuscutae Semen and Raphani Semen were established by optimizing the denatured and annealing temperature, cycle numbers, and etc. When 100 × SYBR Green I was added in the PCR product, strong green fluorescence was visualized under 365 nm UV lamp whereas adulterants showed no florescence. The results indicated that the rapid PCR method can identify Cuscutae Semen and Raphani Semen rapidly. This study provides the technical support for authentication of Chinese medicinal materials.

Systematics and plastid genome evolution of the cryptically photosynthetic parasitic plant genus Cuscuta (Convolvulaceae).

BACKGROUND: The genus Cuscuta L. (Convolvulaceae), commonly known as dodders, are epiphytic vines that invade the stems of their host with haustorial feeding structures at the points of contact. Although they lack expanded leaves, some species are noticeably chlorophyllous, especially as seedlings and in maturing fruits. Some species are reported as crop pests of worldwide distribution, whereas others are extremely rare and have local distributions and apparent niche specificity. A strong phylogenetic framework for this large genus is essential to understand the interesting ecological, morphological and molecular phenomena that occur within these parasites in an evolutionary context. RESULTS: Here we present a well-supported phylogeny of Cuscuta using sequences of the nuclear ribosomal internal transcribed spacer and plastid rps2, rbcL and matK from representatives across most of the taxonomic diversity of the genus. We use the phylogeny to interpret morphological and plastid genome evolution within the genus. At least three currently recognized taxonomic sections are not monophyletic and subgenus Cuscuta is unequivocally paraphyletic. Plastid genes are extremely variable with regards to evolutionary constraint, with rbcL exhibiting even higher levels of purifying selection in Cuscuta than photosynthetic relatives. Nuclear genome size is highly variable within Cuscuta, particularly within subgenus Grammica, and in some cases may indicate the existence of cryptic species in this large clade of morphologically similar species. CONCLUSION: Some morphological characters traditionally used to define major taxonomic splits within Cuscuta are homoplastic and are of limited use in defining true evolutionary groups. Chloroplast genome evolution seems to have evolved in a punctuated fashion, with episodes of loss involving suites of genes or tRNAs followed by stabilization of gene content in major clades. Nearly all species of Cuscuta retain some photosynthetic ability, most likely for nutrient apportionment to their seeds, while complete loss of photosynthesis and possible loss of the entire chloroplast genome is limited to a single small clade of outcrossing species found primarily in western South America.

[Influences of counterfeits on RAPD results of Semen Cuscutae].

Compared the differences of the RAPD results between pure Semen Cuscutae and 12 commercial samples, it comes into the conclusion that the exiting other sample influences the RAPD results when its content is over 60% and the results is same as its content being under 60%.