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Applying chemical elicitors is considered a promising approach for controlling pests in the field. Our previous studies have shown that gibberellin (GA) signaling positively regulates the resistance of rice (Oryza sativa) to the brown planthopper (BPH) Nilaparvata lugens (Stal). Yet, whether the exogenous application of GAs can enhance the resistance of rice to BPH remains unknown. Here, we investigated the influence of exogenous GA3 on both defense responses in rice and BPH performance. We found that pretreating rice with GA3 decreased transcript levels of a mitogen-activated protein kinase (MAPK) and three WRKY transcription factors, as well as levels of BPH-elicited jasmonic acid (JA) and three phenolic acids but increased the release of ethylene. Moreover, GA3 treatment negatively affected the survival and development of BPH nymphs as well as the fecundity of BPH female adults. These findings suggest that GA3 promotes the resistance of rice to BPH and may, thus, be used to improve pest management in rice.

Synthetic chemical elicitors, so called plant strengtheners, can protect plants from pests and pathogens. Most plant strengtheners act by modifying defense signaling pathways, and little is known about other mechanisms by which they may increase plant resistance. Moreover, whether plant strengtheners that enhance insect resistance actually enhance crop yields is often unclear. Here, we uncover how a mechanism by which 4-fluorophenoxyacetic acid (4-FPA) protects cereals from piercing-sucking insects and thereby increases rice yield in the field. Four-FPA does not stimulate hormonal signaling, but modulates the production of peroxidases, H 2 O 2 , and flavonoids and directly triggers the formation of flavonoid polymers. The increased deposition of phenolic polymers in rice parenchyma cells of 4-FPA-treated plants is associated with a decreased capacity of the white-backed planthopper (WBPH) Sogatella furcifera to reach the plant phloem. We demonstrate that application of 4-PFA in the field enhances rice yield by reducing the abundance of, and damage caused by, insect pests. We demonstrate that 4-FPA also increases the resistance of other major cereals such as wheat and barley to piercing-sucking insect pests. This study unravels a mode of action by which plant strengtheners can suppress herbivores and increase crop yield. We postulate that this represents a conserved defense mechanism of plants against piercing-sucking insect pests, at least in cereals.

Fresh kidney beans (Phaseolus vulgaris L.) are common green vegetable that are widely cultured and consumed worldwide. The benefits of fresh kidney beans are highly substantial, but at the same time, toxicity caused by phytohemagglutinin (PHA) has raised concerns. PHA from fresh kidney beans accounted for 40% of poisoning events induced by poisonous plants in China from 2004 to 2013. However, an understanding of PHA levels in fresh kidney beans remains elusive. An analysis method for PHA based on agglutination of PHA to erythrocyte cell was established. We investigated the effect of cultivar, bean part, maturity, and cooking method on PHA content in fresh kidney beans. We demonstrated significant differences in the distribution of PHA among various predominant, fresh Chinese kidney bean cultivars and parts. One major Chinese strain, Zihuayoudou, was found to contain the highest amount of PHA, which was abundant in fresh kidney bean seeds. Moreover, PHA concentrations were found to decrease with the maturity of the fresh product. Further, cooking methods had a significant effect on PHA levels in fresh kidney beans. PHA could be effectively removed when stir-frying for more than 18 min, or braising for more than 10 min. These findings provide insight into the PHA content of fresh kidney beans in China and will be helpful to guide food safety measures.

Lignin is one of the most important components of the plant cell wall, and the expression and transcriptional regulation of lignin biosynthesis-related genes have been studied widely in Arabidopsis and other plants. Citrus fruit juice sacs often undergo lignification, particularly during fruit ripening and storage periods; however, the underlying genetic mechanisms have been little investigated. In this study, we isolated and identified CsMYB330 and CsMYB308 transcription factors, and found that their expression levels are significantly altered during the lignification of citrus fruit juice sacs. We found that CsMYB330 and CsMYB308 can recognize and bind AC elements in the Cs4CL1 promoter and finely regulate expression of the Cs4CL1 gene. In this regulatory process, CsMYB330 was identified as a transcriptional activator, whereas CsMYB308 appears to be a transcriptional repressor. In addition, using a transient assay, we demonstrated that expression of the Cs4CL1 gene is significantly altered in fruit juice sacs overexpressing these two transcription factors. These results indicate that the transcription factors CsMYB330 and CsMYB308 play important roles in the lignification of citrus fruit juice sacs and provide novel insights into the transcriptional regulation associated with fruit juice sac lignification.

Varieties of Citrus are commercially important fruits that are cultivated worldwide and are valued for being highly nutritious and having an appealing flavor. Lignification of citrus fruit juice sacs is a serious physiological disorder that occurs during postharvest storage, for which the underlying transcriptional regulatory mechanisms remain unclear. In this study, we identified and isolated a candidate MYB transcription factor, CsMYB85, that is involved in the regulation of lignin biosynthesis in Citrus sinensis, which has homologs in Arabidopsis and other plants. We found that during juice sac lignification, CsMYB85 expression levels increase significantly, and therefore, suspected that this gene may control lignin biosynthesis during the lignification process. Our results indicated that CsMYB85 binds the CsMYB330 promoter, regulates its expression, and interacts with CsMYB308 in transgenic yeast and tobacco. A transient expression assay indicated that Cs4CL1 expression levels and lignin content significantly increased in fruit juice sacs overexpressing CsMYB85. At4CL1 expression levels and lignin content were also significantly increased in Arabidopsis overexpressing CsMYB85. We accordingly present convincing evidence for the participation of the CsMYB85 transcription factor in fruit juice sac lignification, and thereby provide new insights into the transcriptional regulation of this process in citrus fruits.

The effect of food processing on the level and fate of chiral pesticide residues in apple products has rarely been investigated. In this study, we used ultra-performance convergence chromatography coupled with triple quadrupole mass spectrometry to determine the content of the novel chiral acaricide cyflumetofen. The matrix-matched calibration lines were constructed for apple slices, juice, wine and vinegar, and the determination coefficients (r2) exceeded 0.9954. Acceptable average recoveries were within 81.1% to 119.9%, and the relative standard deviations (RSDs) ranged from 0.8% to 11.0%. Processing effectiveness is represented by the processing factor (PF). The results indicated that the PFs of different procedures (washing, peeling, enzymolysis, fermentation, among others.) were generally less than 1. The reduction of cyflumetofen enantiomers during fermentation was in accordance with first-order kinetics, and stereoselective behavior was observed. This study provides reliable references for the risk assessment of cyflumetofen in the processing of apple products.

Heteropoly acids were used as catalysts for cyclodehydration of various 1, n -diols. Cyclodehydration of butane-1,4-diol, pentane-1,5-diol and hexane-1,6-diol catalysed by H 3 PW 12 O 40 gave tetrahydrofuran, tetrahydropyran and oxepane, respectively. Cyclodehydration of diethylene glycol, triethylene glycol, diethylene glycol monomethyl ether and polyethylene glycol 200 catalysed by H 3 PW 12 O 40 gave 1,4-dioxane. In particular, cyclodehydration of hexane-1,6-diol gave an excellent yield of oxepane (80%). The selectivity exhibited by the H 3 PW 12 O 40 catalyst was even better than that exhibited by other reported catalyst systems for similar cyclodehydration reactions.

Ultra-performance convergence chromatography is an environmentally-friendly analytical method that uses dramatically reduced amounts of organic solvents. In addition, a robust and highly sensitive chiral separation method was developed for the novel chiral acaricide cyflumetofen by using ultra-performance convergence chromatography coupled with tandem mass spectrometry, which shows that stereoisomer recoveries determined for various apple parts ranged from 78.3% to 119.9%, with the relative standard deviations being lower than 14.0%. The half-lives of (−)-cyflumetofen and (+)-cyflumetofen obtained under 5-fold applied dosage equal to 22.13 and 22.23 days, respectively. For 1.5-fold applied dosage, the respective values were determined as 22.42 and 23.64 days, i.e., the degradation of (−)-cyflumetofen was insignificantly favored over that of its enantiomer. Importantly, cyflumetofen was unevenly distributed in apples, with its relative contents in apple peel, peduncle, and pomace equal to 50%, 22%, and 16%, respectively. The proposed method can be used to efficiently separate and quantify chiral pesticide with advantages of a shorter analysis time, greater sensitivity, and better environmental compatibility. Additionally, the consumption of apples with residue of cyflumetofen did not pose a health risk to the population if the cyflumetofen applied under satisfactory agricultural practices after the long-term dietary risk assessment.