Moringa oleifera Lam. (MO) is called the “Miracle Tree” because of its extensive pharmacological activity. In addition to being an important food, it has also been used for a long time in traditional medicine in Asia for the treatment of chronic diseases such as diabetes and obesity. In this study, by constructing a library of MO phytochemical structures and using Discovery Studio software, compounds were subjected to virtual screening and molecular docking experiments related to their inhibition of dipeptidyl peptidase (DPP-IV), an important target for the treatment of type 2 diabetes. After the four-step screening process, involving screening for drug-like compounds, predicting the absorption, distribution, metabolism, excretion, and toxicity (ADME/T) of pharmacokinetic properties, LibDock heatmap matching analysis, and CDOCKER molecular docking analysis, three MO components that were candidate DPP-IV inhibitors were identified and their docking modes were analyzed. In vitro activity verification showed that all three MO components had certain DPP-IV inhibitory activities, of which O-Ethyl-4-[(α-l-rhamnosyloxy)-benzyl] carbamate (compound 1) had the highest activity (half-maximal inhibitory concentration [IC₅₀] = 798 nM). This study provides a reference for exploring the molecular mechanisms underlying the anti-diabetic activity of MO. The obtained DPP-IV inhibitors could be used for structural optimization and in-depth in vivo evaluation.

Background: Fusarium oxysporum f. sp. cucumerinum (FOC) is the causal agent of cucumber Fusarium wilt, which can cause extensive damages and productivity losses. Cucurbita ficifolia Bouché (Cucurbitaceae) is usually used as rootstock for cucumber because of its excellent resistance to Fusarium wilt. Our previous study found that C.ficifolia has high FOC resistance, the underlying mechanism of which is unclear. Results: Transcriptome and proteome profiling was performed on the basis of RNA-Seq and isobaric tag for relative and absolute quantitation technology to explore the molecular mechanisms of the response of Cucurbita ficifolia Bouché to Fusarium oxysporum f. sp. cucumerium infection. Comparative analyses revealed that 1850 genes and 356 protein species were differentially regulated at 2d and 4d after FOC inoculation. However, correlation analysis revealed that only 11 and 39 genes were differentially regulated at both the transcriptome and proteome levels after FOC inoculation at 2d and 4d, respectively. After FOC inoculation, plant hormones signal transduction, transcription factors were stimulated, whereas wax biosynthesis and photosynthesis were suppressed. Increased synthesis of oxidative-redox proteins is involved in resistance to FOC. Conclusions: This study is the first to reveal the response of C. ficifolia leaf to FOC infection at the transcriptome and proteome levels, and to show that FOC infection activates plant hormone signaling and transcription factors while suppressing wax biosynthesis and photosynthesis. The accumulation of oxidative-redox proteins also plays an important role in the resistance of C. ficifolia to FOC. Results provide new information regarding the processes of C. ficifolia leaf resistance to FOC and will contribute to the breeding of cucumber rootstock with FOC resistance.

Background: The plant cysteine-rich receptor-like kinases (CRKs) are a large family having multiple roles, including defense responses under both biotic and abiotic stress. However, the CRK family in cucumbers (Cucumis sativus L.) has been explored to a limited extent. In this study, a genome-wide characterization of the CRK family has been performed to investigate the structural and functional attributes of the cucumber CRKs under cold and fungal pathogen stress. Results: A total of 15 C. sativus CRKs (CsCRKs) have been characterized in the cucumber genome. Chromosome mapping of the CsCRKs revealed that 15 genes are distributed in cucumber chromosomes. Additionally, the gene duplication analysis of the CsCRKs yielded information on their divergence and expansion in cucumbers. Phylogenetic analysis divided the CsCRKs into two clades along with other plant CRKs. Functional predictions of the CsCRKs suggested their role in signaling and defense response in cucumbers. The expression analysis of the CsCRKs by using transcriptome data and via qRT-PCR indicated their involvement in both biotic and abiotic stress responses. Under the cucumber neck rot pathogen, Sclerotium rolfsii infection, multiple CsCRKs exhibited induced expressions at early, late, and both stages. Finally, the protein interaction network prediction results identified some key possible interacting partners of the CsCRKs in regulating cucumber physiological processes. Conclusions: The results of this study identified and characterized the CRK gene family in cucumbers. Functional predictions and validation via expression analysis confirmed the involvement of the CsCRKs in cucumber defense response, especially against S. rolfsii. Moreover, current findings provide better insights into the cucumber CRKs and their involvement in defense responses.

Cucumber cultivation suffers from severe yield and quality decline due to cold damage. Cucurbita ficifolia is used as a rootstock for grafting cucumber to improve resistance due to its excellent resistance. This study used Yunnan C. ficifolia as the rootstock and Jingyan Xiamei 2 cucumber as the scion, simulating common low-temperature stress of 15 °C, 10 °C, and 5 °C in an artificial climate chamber, to study the mechanism of cucumber-grafted seedlings responding to low temperatures in terms of growth and development, photosynthesis, osmotic regulation substances, antioxidant system, and gene expression. The results showed that the growth and development of grafted seedlings of C. ficifolia was less inhibited, the chlorophyll content was less reduced, and the content of osmoregulatory substances was significantly increased under low-temperature stress. The activity of antioxidant enzymes in grafted seedlings of C. ficifolia was significantly upregulated at low temperatures, and the expression of antioxidant enzyme genes was consistently higher in grafted seedlings of C. ficifolia. These results confirmed that C. ficifolia as a rootstock could improve the cold resistance of cucumber. Collectively, this study provides the basis for revealing the physiological and molecular mechanism of grafting seedlings to improve cucumber’s low temperature tolerance.

Malania oleifera is a rare and threatened medicinal plant in China. In this study, the complete chloroplast genome (cp) of M. oleifera was sequenced, assembled, and analyzed. The circular complete cp genome of M. oleifera was 158,163 bp in length and contained a large single copy region (LSC, 87,212 bp), a small single copy region (SSC, 439 bp), and 2 short inverted repeat (IRa and IRb) regions (35,256 bp). The cp genome encodes 97 unique genes, including 62 protein-coding genes, 30 transfer RNA genes, 4 ribosomal RNA genes, and a pseudogene. Phylogenetic analysis of M. oleifera showed that M. oleifera was the sister group with Champereia manillana from Opiliaceae and Osyris alba from Santalaceae.

Moringa oleifera Lam. is a member of the Moringaceae family which includes 13 species. The plant is cultivated throughout tropical and subtropical areas due to its adaptability, also used worldwide as nutritional supplement and traditional medicine. In this study, the complete chloroplast genome (cp) of M. oleifera was sequenced, assembled, and analyzed. Our results indicated that the cp genome of M. oleifera was 160,600 bp in length, containing a large single copy (LSC, 88,727 bp) region and a small single copy (SSC, 18,883 bp) region which separated by two reduced inverted repeats (IRs, 26,495 bp). A total of 108 unique genes were identified, including 74 protein-coding genes, 30 transfer RNA (tRNA) genes, and four ribosomal RNA (rRNA) genes. The overall GC content of M. oleifera cp genome was 36.8%. Most of the 47 simple sequence repeats (SSRs) were mononucleotides motifs of A/T types and were found to be located in non-coding regions. Phylogenetic analysis of M. oleifera showed that M. oleifera was the base group of Rhoeadales with strongly bootstrap supported which is consist with morphological taxonomy.