Simultaneous Screening of 733 Pesticide Residues in Fruits and Vegetables by a GC/LC-Q-TOFMS Combination Technique

In this paper,we report the construction of two accurate mass databases and the development of a combination detection method that simultaneously screens for 733 pesticide and chemical contaminant multi-residues via high-throughput liquid chromatography(LC)-and gas chromatography(GC)-quadru pole-time-of-flight mass spectrometry(Q-TOFMS).This work demonstrates that electronic mass spectral standards may replace chemical-source standard materials as references through one sample preparation and the combination of GC/LC-Q-TOFMS screening.This cutting-edge technique has also replaced multiresidue determination using targeted detection with non-targeted screening.The pesticide residue types,sensitivity,recovery,and reproducibility of this combination technique are evaluated in eight fruit and vegetable matrices.This technique shows three advantages:①In comparison with the discovery capability of a single technique,the combination technique shows an improvement of 51.1%(GC-QTOFMS)and 39.6%(LC-Q-TOFMS),respectively;②the combination technique can satisfy a screening limit lower than 10μg·kg^-1 and meet the requirements of“uniform standards,”although some of the pesticide residues could be optimized to further improve screening sensitivity;③over 488 pesticides with recoveries between 60%-120%and relative standard deviation(RSD)<20%at a spiked level of 10μg·kg^-1 were detected with the combination technique in eight different matrices.From 2012 to 2017,this combination technique was applied in an investigation to screen pesticide residues from 1384 sampling locations for 38138 batched samples covering 18 categories and 134 types of fruits and vegetables obtained from across the mainland of China.After statistical analysis,533 pesticides in 115891 determinations were detected,and the regularity of pesticides in the fruits and vegetables sold on the Chinese market was shown.

Identification of yellowhorn(Xanthoceras sorbifolium)WRKY transcription factor family and analysis of abiotic stress response model

WRKY transcription factors are widely distributed in higher plants and play important roles in many biological processes,including stress resistance.The recently published genome sequence of yellowhorn,an oil tree with robust resistance to cold,drought,heat,salt and alkali,provides an excellent opportunity to identify and characterize the entire yellowhorn WRKY protein family and a basis for the study of abiotic stress resistance of WRKY gene family in forest species.In the present comprehensive analysis of WRKY transcription factors in yellowhorn,65 WRKY genes were identified and defined based on their location on the chromosome.According to their structure and phylogenetic relationships,XsWRKY genes clustered into WRKY groupsⅠ-Ⅲ.Segmental duplication events played a significant role in the expansion of WRKY gene family.Furthermore,transcriptomic data and real-time quantitative PCR analysis showed that expression of XsWRKY genes responding to salt and drought stresses and a hormone treatment.We also determined structures of the encoded proteins,c is-elements of the promoter region,and expression patterns.These results provide a foundation for the study of the biological function of WRKY transcription factors in yellowhorn.

Identifi cation and characterization of the bZIP transcription factor family in yellowhorn

The basic leucine zipper(bZIP)transcription factor family is one of the largest and most diverse families in plants,regulating plant growth and development and playing an essential role in response to abiotic and biotic stresses.However,little is known about the biological functions of bZIP proteins in yellowhorn(Xanthoceras sorbifolium).Recently,64 XsbZIP genes were identifi ed in the yellowhorn genome and found to be disproportionately distributed in linkage groups.The XsbZIP proteins clustered into 11 groups based on their phylogenetic relationships with AtbZIP,ZmbZIP and GmbZIP proteins.Five intron patterns in the basic and hinge regions and additional conserved motifs were defi ned,both supporting the group classifi cation and possibly contributing to their functional diversity.Compared to tandem duplication,the segment duplication greatly contributed to the expansion of yellowhorn bZIP genes.In addition,most XsbZIP genes harbor several stress responsive cis-elements in their promoter regions.Moreover,the RNA-seq and qRT-PCR data indicated XsbZIP genes were extensively involved in response to various stresses,including salt(NaCl),cold and abscisic acid,with possibly diff erent molecular mechanisms.These results provide a new understanding of the biological functions of bZIP transcription factors in yellowhorn.