Safflower (Carthamus tinctorius L.) has long been grown as a crop due to its commercial utility as oil, animal feed, and pharmacologically significant secondary metabolites. The integration of omics approaches, including genomics, transcriptomics, metabolomics, and proteomics datasets, has provided more comprehensive knowledge of the chemical composition of crop plants for multiple applications. Knowledge of a metabolome of plant is crucial to optimize the evolution of crop traits, improve crop yields and quality, and ensure nutritional and health factors that provide the opportunity to produce functional food or feedstuffs. Safflower contains numerous chemical components that possess many pharmacological activities including central nervous, cardiac, vascular, anticoagulant, reproductive, gastrointestinal, antioxidant, hypolipidemic, and metabolic activities, providing many other human health benefits. In addition to classical metabolite studies, this review focuses on several metabolite-based working techniques and updates to provide a summary of the current medical applications of safflower.

Meloidogyne incognita is a devastating plant parasitic nematode that causes root knot disease in a wide range of plants. In the present study, we investigated host-induced RNA interference (RNAi) gene silencing of chitin biosynthesis pathway genes (chitin synthase, glucose-6-phosphate isomerase, and trehalase) in transgenic tobacco plants. To develop an RNAi vector, ubiquitin (UBQ1) promoter was directly cloned, and to generate an RNAi construct, expression of three genes was suppressed using the GATEWAY system. Further, transgenic Nicotiana benthamiana lines expressing dsRNA for chitin synthase (CS), glucose-6-phosphate isomerase (GPI), and trehalase 1 (TH1) were generated. Quantitative PCR analysis confirmed endogenous mRNA expression of root knot nematode (RKN) and revealed that all three genes were more highly expressed in the female stage than in eggs and in the parasitic stage. In vivo, transformed roots were challenged with M. incognita. The number of eggs and root knots were significantly decreased by 60–90% in RNAi transgenic lines. As evident, root galls obtained from transgenic RNAi lines exhibited 0.01- to 0.70-fold downregulation of transcript levels of targeted genes compared with galls isolated from control plants. Furthermore, phenotypic characteristics such as female size and width were also marginally altered, while effect of egg mass per egg number in RNAi transgenic lines was reduced. These results indicate the relevance and significance of targeting chitin biosynthesis genes during the nematode lifespan. Overall, our results suggest that further developments in RNAi efficiency in commercially valued crops can be applied to employ RNAi against other plant parasitic nematodes.

The genus Carthamus is a diverse group of plants belonging to the family Compositae. Florets of Carthamus species exhibit various colors, including white, yellow, orange, and red, which are related to their metabolite compositions. We aimed to investigate the metabolites accumulated in florets of three wild (C. lanatus, C. palaestinus, and C. turkestanicus) and one cultivated (C. tinctorius) species of safflower at three developmental stages. Metabolites were extracted from freeze-dried florets using 70% methanol; qualification and quantification were carried out using liquid chromatography quadrupole time-of-flight mass spectrometry in positive and negative ion modes followed by extraction of the peaks. Fifty-six metabolites, including phenylpropanoids, chalcones, isoflavonoids, flavanones, flavonols, flavones, and other primary metabolites, were identified for the first time in safflower wild species. The orange florets contained high abundances of safflomin A, anhydrosafflor yellow B, and baimaside, whereas white/cream and light-yellow pigmented florets had high abundances of 1,5-dicaffeoylquinic acid, luteolin 7-O-glucuronide, and apigenin 7-O-β-D-glucuronide. The principal component analysis clearly distinguished the samples based on their pigment types, indicating that color is a dominant factor dictating the identity and amount of the metabolites. Pearson correlation data based on levels of metabolites showed that orange and yellow florets were significantly correlated to each other. White and cream pigmented species were also highly correlated. Comparison between three developmental stages of safflower wild species based on their metabolite profile showed inconsistent. The findings of this study broaden the current knowledge of safflower metabolism. The wide diversity of metabolites in safflower materials also helps in efforts to improve crop quality and agronomic traits.

Triacylglycerols (TAGs) are the storage oils of plant seeds, and these lipids provide energy for seed germination and valuable oils for human consumption. Three diacylglycerol acyltransferases (DGAT1, DGAT2, and DGAT3) and phospholipid:diacylglycerol acyltransferases participate in the biosynthesis of TAGs. DGAT1 and DGAT2 participate in the biosynthesis of TAGs through the endoplasmic reticulum (ER) pathway. In this study, we functionally characterized CsDGAT1 and CsDGAT2 from camelina (Camelina sativa). Green fluorescent protein-fused CsDGAT1 and CsDGAT2 localized to the ER when transiently expressed in Nicotiana benthamiana leaves. To generate Csdgat1 and Csdgat2 mutants using the CRISPR/Cas9 system, camelina was transformed with a binary vector carrying Cas9 and the respective guide RNAs targeting CsDGAT1s and CsDGAT2s via the Agrobacterium-mediated floral dip method. The EDD1 lines had missense and nonsense mutations in the CsDGAT1 homoeologs, suggesting that they retained some CsDGAT1 function, and their seeds showed decreased eicosaenoic acid (C20:1) contents and increased C18:3 contents compared to the wild type (WT). The EDD2 lines had a complete knockout of all CsDGAT2 homoeologs and a slightly decreased C18:3 content compared to the WT. In conclusion, CsDGAT1 and CsDGAT2 have a small influence on the seed oil content and have an acyl preference for C20:1 and C18:3, respectively. This finding can be applied to develop oilseed plants containing high omega-3 fatty acids or high oleic acid.

Various bio-based recombinant proteins have been produced for industrial, medical, and research purposes. Plants are potential platforms for recombinant protein production because of several advantages. Therefore, establishing a system with high target gene expression to compensate for the low protein yield of plant systems is crucial. In particular, selecting and combining strong terminators is essential because the expression of target genes can be substantially enhanced. Here, we aimed to quantify the enhancement in the fluorescence intensity of the turbo green fluorescence protein (tGFP) caused by the best double-terminator combinations compared to that of the control vector using agroinfiltration in Nicotiana benthamiana leaves. tGFP fluorescence increased by 4.1-fold in leaf samples infiltrated with a vector containing a double terminator and markedly increased by a maximum of 23.7-fold when co-infiltrated with the geminiviral vector and P19 compared to that in constructs containing an octopine synthase terminator. Polyadenylation site analysis in leaf tissues expressing single or dual terminators showed that the first terminator influenced the polyadenylation site determination of the second terminator, resulting in different polyadenylation sites compared with when the terminator is located first. The combination of the high-expression terminators and geminiviral vectors can increase the production of target proteins.

Cyst nematodes remain a major threat to global agricultural production, causing huge losses. To understand the parasitism of the cyst nematodes Heterodera trifolii (HT) and Heterodera schachtii (HS), we constructed whole-genome assemblies using short- and long-read sequencing technologies. The nematode genomes were 379 Mb and 183 Mb in size, with the integrated gene models predicting 40,186 and 18,227 genes in HT and HS, respectively. We found more than half of the genes predicted in HT (64.7%) and HS (53.2%) were collinear to their nearest neighbor H. glycines (HG). Large-scale duplication patterns in HT and segmental duplications of more than half of the orthologous genes indicate that the genome of HT is polyploid in nature. Functional analysis of the genes indicated that 65.6% of the HG genes existed within the HT genome. Most abundant genes in HT and HS were involved in gene regulation, DNA integration, and chemotaxis. Differentially expressed genes showed upregulation of cuticle structural constituent genes during egg and female stages and cytoskeletal motor activity-related genes in juvenile stage 2 (J2). Horizontal gene transfer analyses identified four new vitamin biosynthesis genes, pdxK, pdxH, pdxS, and fabG, of bacterial origin, to be first reported in HT and HS. Mitogenomes of HT, HS, and HG showed similar structure, composition, and codon usage. However, rates of substitution of bases in the gene nad4l were significantly different between HT and HS. The described genomes, transcriptomes, and mitogenomes of plant-parasitic nematodes HT and HS are potential bio-resources used to identify several strategies of control of the nematode.