Integration analysis of PacBio SMRT- and Illumina RNA-seq reveals P450 genes involved in thiamethoxam detoxification in Bradysia odoriphaga

Enhancement of tolerance against flonicamid in Solenopsis invicta (Hymenoptera: Formicidae) through overexpression of CYP6A14

Solenopsis invicta is a main issue in southern China and is causing significant damage to the local ecological environment. The extensive use of insecticides has resulted in the development of tolerance in S. invicta. In our study, ten S. invicta colonies from Sichuan Province exhibited varying degrees of tolerance against flonicamid, with LC50 values from 0.49 mg/L to 8.54 mg/L. The sensitivity of S. invicta to flonicamid significantly increased after treatment with the P450 enzyme inhibitor piperonyl butoxide (PBO). Additionally, the activity of P450 in S. invicta was significantly enhanced after being treated with flonicamid. Flonicamid induced the expression levels of CYP4aa1, CYP9e2, CYP4C1, and CYP6A14. The expression levels of these P450 genes were significantly higher in the tolerant colonies compared to the sensitive colonies, and the relative copy numbers of CYP6A14 in the tolerant colonies were 2.01-2.15 fold. RNAi feeding treatment effectively inhibited the expression of P450 genes, thereby reducing the tolerance of S. invicta against flonicamid. In addition, the overexpression of CYP6A14 in D. melanogaster resulted in reduced sensitivity to flonicamid. Our investigations revealed hydrophobic interactions between flonicamid and seven amino acid residues of CYP6A14, along with the formation of a hydrogen bond between Glu306 and flonicamid. Our findings suggest that flonicamid can effectively control S. invicta and P450 plays a pivotal role in the tolerance of S. invicta against flonicamid. The overexpression of CYP6A14 also increased tolerance to flonicamid.

Aliens in the CYPome of the black fungus gnat, Bradysia coprophila

The diverse cytochrome P450 enzymes of insects play essential physiological roles and also play important roles in the metabolism of environmental chemicals such as insecticides. We manually curated the complement of P450 (CYP) genes, or CYPome, of the black fungus gnat, Bradysia (Sciara) coprophila (Diptera, Sciaroidea), a species with a variable number of chromosomes. This CYPome carries two types of "alien" P450 genes. The first type of alien P450s was found among the 163 CYP genes of the core genome (autosomes and X). They consist of 28 sequences resulting from horizontal gene transfer, with closest sequences not found in insects, but in other arthropods, often Collembola. These genes are not contaminants, because they are expressed genes with introns, found in synteny with regular dipteran genes, also found in B. odoriphaga and B. hygida. Two such "alien" genes are representatives of CYP clans not otherwise found in insects, a CYP53 sequence related to fungal CYP53 genes, and a CYP19-like sequence similar to some collembolan sequences but of unclear origin. The second type of alien P450s are represented by 99 sequences from germline-restricted chromosomes (GRC). While most are P450 pseudogenes, 33 are apparently intact, with half being more closely related to P450s from Cecidomyiidae than from Sciaridae, thus supporting the hypothesis of a cross-family hybridization origin of the GRC.

Moderate Salinity of Nutrient Solution Improved the Nutritional Quality and Flavor of Hydroponic Chinese Chives (Allium tuberosum Rottler)

Sodium chloride (NaCl), as a eustressor, can trigger relevant pathways to cause plants to produce a series of metabolites, thus improving the quality of crops to a certain extent. However, there are few reports on the improvement of nutrient quality and flavor of hydroponic Chinese chives (Allium tuberosum Rottler) by sodium chloride. In this study, five NaCl concentrations were used to investigate the dose-dependent effects on growth, nutritional quality and flavor in Chinese chives. The results show that 10 mM NaCl had no significant effect on the growth of Chinese chives, but significantly decreased the nitrate content by 40% compared with 0 mM NaCl treatment, and the content of soluble protein and vitamin C was increased by 3.6% and 2.1%, respectively. In addition, a total of 75 volatile compounds were identified among five treatments using headspace solid-phase microextraction gas chromatography/mass spectrometry (HS-SPME/GC-MS). Compared with the 0 mM NaCl treatment, 10 mM NaCl had the greatest effect on the quantity and content of volatile compounds, with the total content increased by 27.8%. Furthermore, according to the odor activity values (OAVs) and odor description, there were 14 major aroma-active compounds (OAVs > 1) in Chinese chives. The “garlic and onion” odor was the strongest among the eight categories of aromas, and its highest value was observed in the 10 mM NaCl treatment (OAVs = 794).Taken together, adding 10 mM NaCl to the nutrient solution could improve the nutritional quality and flavor of Chinese chives without affecting their normal growth.