Transcriptome-based analysis of key pathways relating to yield formation stage of foxtail millet under different drought stress conditions.

Although foxtail millet, as small Panicoid crop, is of drought resilient, drought stress has a significant effect on panicle of foxtail millet at the yield formation stage. In this study, the changes of panicle morphology, photosynthesis, antioxidant protective enzyme system, reactive oxygen species (ROS) system, and osmotic regulatory substance and RNA-seq of functional leaves under light drought stress (LD), heavy drought stress (HD), light drought control (LDCK) and heavy drought control (HDCK) were studied to get a snap-shot of specific panicle morphological changes, physiological responses and related molecular mechanisms. The results showed that the length and weight of panicle had decreased, but with increased empty abortive rate, and then yield dropped off 14.9% and 36.9%, respectively. The photosynthesis of millet was significantly decreased, like net photosynthesis rate, stomatal conductance and transpiration rate, especially under HD treatment with reluctant recovery from rehydration. Under LD and HD treatment, the peroxidase (POD) was increased by 34% and 14% and the same as H2O2 by 34.7% and 17.2% compared with LDCK and HDCK. The ability to produce and inhibit O2- free radicals under LD treatment was higher than HD. The content of soluble sugar was higher under LD treatment but the proline was higher under HD treatment. Through RNA-seq analysis, there were 2,393 and 3,078 different genes expressed under LD and HD treatment. According to the correlation analysis between weighted gene coexpression network analysis (WGCNA) and physiological traits, the co-expression network of several modules with high correlation was constructed, and some hub genes of millet in response to drought stress were found. The expression changes relating to carbon fixation, sucrose and starch synthesis, lignin synthesis, gibberellin synthesis, and proline synthesis of millet were specifically analyzed. These findings provide a full perspective on how drought affects the yield formation of foxtail millet by constructing one work model thereby providing theoretical foundation for hub genes exploration and drought resistance breeding of foxtail millet.

Characterization of lipid profiling in three parts (muscle, head and viscera) of tilapia (Oreochromis niloticus) using lipidomics with UPLC-ESI-Q-TOF-MS.

A lipidomic evaluation was performed on the tilapia muscle, head and viscera, including studying the composition, distribution and stereospecific characteristics of fatty acids and lipid species. The head and viscera lipids were significantly richer than the muscle lipids. Triacylglycerols were the predominant fraction (over 80% of total lipid in the muscle and head). Additionally, polyunsaturated fatty acids had higher percentages in phospholipids (30.35-52.05% of total fatty acids) than in triacylglycerols (18.11-25.15%). The C52:2 and C52:3 were the most abundant triacylglycerols, which indicates the potential application in infant food. Moreover, 622, 530 and 513 lipids were identified using ultraperformance liquid chromatography-quadrupole time-of-flight-mass spectrometry in the muscle, head and viscera, respectively. The three tilapia parts were distinguished using multivariate analysis. Five fatty acids and 33 lipid species were considered as the potential biomarkers. This comprehensive analysis will help to evaluate the lipid nutritional values and facilitate exploitation in tilapia consumption and processing.

A comprehensive study of lipid profiles of round scad (Decapterus maruadsi) based on lipidomic with UPLC-Q-Exactive Orbitrap-MS.

Round scad (Decapterus maruadsi) is rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, there is no comprehensive information covering its lipidomic profile. In this study, lipid profiles including fatty acid composition, distribution and detailed structure information were explored using gas chromatography-flame ionization detector (GC-FID) and ultra-high-performance liquid chromatography coupled with hybrid quadrupole-orbitrap mass spectrometry (UPLC-Q-Exactive Orbitrap-MS). The results showed that triacylglycerol (TG) was the dominant class, and the EPA and DHA were concentrated as glycerophospholipid (GP). The saturated fatty acids and monounsaturated fatty acids were mainly esterified in positions 1 and 3 of TG and sn-1-position of GP, while the polyunsaturated fatty acids (PUFA) were mainly esterified in sn-2-position of TG and GP. A total of 1282 species from six classes (21 subclasses) including glycerolipids (GL), sphingolipids (SP), GP, fatty acyls (FA), saccharolipids (SL) and prenol lipids (PR) were identified. Several molecular species were characterized with PUFA, especially EPA and DHA in GP. Considering the superior fatty acids composition and distribution of round scad, it is deserved for further exploitation of its marine lipid source on account of the healthy and nutritional functions.