Subchronic Toxicity Evaluation of Idesia polycarpa Fruit Oil by 90-Day Oral Exposure in Wistar Rats

Idesia polycarpa, belonging to the Flacourtiaceae family, is a tall deciduous tree, widely distributed in some Asian countries. It is famous for its high yield of fruit known as oil grape, which is rich of linoleic acid and linolenic acid, and so on. To provide evidences for its safe use as food, subchronic toxicity of I. polycarpa fruit oil and no observed adverse effect level were performed in male and female specific pathogen-free Wistar rats. Based on the Organization for Economic Co-operation and Development guidelines, the oil was orally administered to rats by gavage at 0, 1.0, 2.0, and 4.0mL/kg.bw/day for 90 days, followed by a 28-day recovery period. The results showed that no sign of oil-related toxicity, clinically or histologically, was observed in both male and female rats. Although there was a slight increase or decrease in some indicators such as hematology, serum chemistry, and so on, those changes were all within the normal ranges, and as presented in the 90-day study, the oil exhibited no toxic effect compared to the control rats. I. polycarpa might be a potential excellent and healthy vegetable oil resource.

Analysis of Leaf and Soil Nutrients, Microorganisms and Metabolome in the Growth Period of Idesia polycarpa Maxim

Idesia polycarpa Maxim is an emerging oil plant species. Understanding its microecological characteristics and internal mechanisms can serve as a basis for field management and the screening and application of growth-promoting bacteria during the growth phase of young trees. This study used three-year-old young I. polycarpa to analyze the tree's root morphology, soil, and leaf nutrient status variations from May to October. In addition, differences in the rhizosphere soil, leaf metabolites, and microorganisms were observed. The results showed that, from May to October, the total nitrogen (TN) in the soil significantly decreased, whereas the TN, total potassium (TK), and total phosphorus (TP) in the leaves differed (p < 0.05). The leaf-dominant bacteria changed from Pseudomonadota to Firmicutes phylum. In addition, the relative abundance of soil and leaf-dominant bacteria decreased. The study found that the soil and leaf differential metabolites were mainly sugars and phenolic acids. The soil bacterial community showed a significant correlation with soil pH, available potassium (AK), available phosphorus (AP), and TN (p < 0.05). Further, the soil fungal community was significantly correlated with pH and AK (p < 0.001). TP, pH, and TK were the main factors influencing the leaf bacterial community, while the leaf fungal community was significantly correlated with five factors, including pH, TC, and TN. The root morphology was also mainly affected by pH, Pedomicrobium sp., Talaromyces sp., Penicillium sp., and D-Mannitol 2.

Characterization of diacylglycerol acyltransferase 2 from Idesia polycarpa and function analysis

Idesia polycarpa is an oil-producing tree native to China and Northeast Asia. The fruits of I. polycarpa which are named oil grape are unique in that they contain large amounts saturated and unsaturated lipids. Diacylglycerol acyltransferase 2 (DGAT2) is a key enzyme catalyzing the final step of triacylglyceride (TAG) synthesis. However, expression and bioinformatics of DGAT2 in I. polycarpa are still blank. In order to further understand the lipogenesis of oil grape, we contrasted seven various growth periods fruits from seed formation to seed maturation. Lipid accumulation rates and final lipid content were significantly different among the different periods. We cloned and characterized the DGAT2 gene from fruits of I. polycarpa. A partial fragment of 239 bp of IpDGAT2 was amplified by PCR. We cloned the open-reading frame (ORF) of IpDGAT2 by RACE technique. The ORF of IpDGAT2 contains 984 bp and encodes 327 amino acids. The qPCR analysis manifested that IpDGAT2 was expressed in all oil grape growing periods and expression was highest on September 20 (seed maturation). In I. polycarpa fruits the expression of IpDGAT2 was positively correlated with the lipid accumulation rates. Rhodotorula glutinis expression analysis showed that IpDGAT2 have a diacylglycerol acyltransferase bio-functional. Heterologous expression of the 35S::IpDGAT2 in Arabidopsis thaliana confirmed that the isolated IpDGAT2 could catalyze lipid synthesis. The lipid content increased by 40 % in transgenic plants relative to the control. which suggests that high lipid content fruits can be created by the overexpression of IpDGAT2 in I. polycarpa.

Molecular cloning and function analysis of FAD2 gene in Idesia polycarpa

Idesia polycarpa is a valuable oil-producing tree and can potentially be used for edible oil and biofuel production. The fruits of I. polycarpa are unique in that they contain both saturated and unsaturated lipids. Fatty acid desaturase 2 (FAD2), also as known as omega-6 fatty acid desaturase in endoplasmic, is a key enzyme for linoleic acid and α-linolenic acid biosynthesis. However, bioinformatics and expression of FAD2 in I. polycarpa are still absent. Here, to gain insight into the lipid and linoleic synthesis of I. polycarpa, we compared the fruits from different growth stages. Lipid accumulation rates, final lipid content, linoleic accumulation rates and final linoleic content were significantly different among the different stages. In a further step, the FAD2 gene from fruits of I. polycarpa, named IpFAD2, was cloned and characterized. A partial fragment of 169 bp of IpFAD2 was amplified by degenerate PCR. Full cDNA of IpFAD2 was obtained by the RACE technique. The open-reading frame of IpFAD2 was 1149 bp in length, encoding 382 amino acids. A comparison of the deduced amino acids sequence of IpFAD2 with FAD2 from other species showed high similarities, ranging from 78.8 to 92.6%. The IpFAD2-predicted protein has a theoretical molecular mass of 44.03 kDa and an isoelectric point (pI) of 8.04. It has five transmembrane helices located on the endoplasmic reticulum. The IpFAD2-predicted protein was classified as belonging to the Membrane-FADS-like superfamily based on its conserved domain analysis. Expression analysis based on qRT-PCR indicated that IpFAD2 was expressed in different fruit growth stages, with the highest expression level at 80 DAP and the lowest at 130 DAP. The expression of IpFAD2 was positively correlated with the linoleic accumulation rates in I. polycarpa fruits. Prokaryotic expression in Escherichia. Coli BL21(DE3) indicated that IpFAD2 gene could encode a bio-functional omega-6 fatty acid desaturase. Heterologous expression in Arabidopsis thaliana confirmed that the isolated IpFAD2 proteins could catalyse linoleic synthesis. This is the first cloning and expression analysis of FAD2 from I. polycarpa, significantly contributing to our understanding of the role of IpFAD2 in linoleic synthesis, esp. in terms of genetic engineering breeding for linoleic production.

Idesia polycarpa (Salicaceae) leaf constituents and their toxic effect on Cerura vinula and Lymantria dispar (Lepidoptera) larvae

Phytochemical investigation of Idesia polycarpa (Salicaceae) resulted in the structure elucidation of nine previously undescribed phenolic natural products along with six known compounds. The compounds are structurally related to salicinoids that are known defense compounds from Salix and Populus species. The I. polycarpa diet was toxic, as shown in feeding experiments with larvae of Lymantria dispar, an herbivorous broadleaf tree generalist insect, and with larvae of Cerura vinula, a specialist adapted to poplar. The survival rate and mass gain of larvae was significantly lower when they fed on I. polycarpa leaves, compared to larvae fed on Populus nigra leaves. Potential reasons for the poor performance of both herbivores on I. polycarpa leaves are discussed.

De novo Assembly and Characterization of the Fruit Transcriptome of Idesia polycarpa Reveals Candidate Genes for Lipid Biosynthesis

Idesia polycarpa, is a valuable oilseed-producing tree of the Flacourtiaceae family that has the potential to fulfill edible oil production and is also a possible biofuel feedstock. The fruit is unique in that it contains both saturated and unsaturated lipids present in pericarp and seed, respectively. However, triglyceride synthesis and storage in tissues outside of the seeds has been poorly studied in previous researches. To gain insight into the unique properties of I. polycarpa fruit lipid synthesis, biochemical, and transcriptomic approaches were used to compare the lipid accumulation between pericarp and seed of the fruit. Lipid accumulation rates, final lipid content and composition were significantly different between two tissues. Furthermore, we described the annotated transcriptome assembly and differential gene expression analysis generated from the pericarp and seed tissues. The data allowed the identification of distinct candidate genes and reconstruction of lipid pathways, which may explain the differences of oil synthesis between the two tissues. The results may be useful for engineering alternative pathways for lipid production in non-seed or vegetative tissues.