Exogenous 24-epibrassinolide activates detoxification enzymes to promote degradation of boscalid in cherry tomatoes

SlbHLH22-Induced Hypertrophy Development Is Related to the Salt Stress Response of the GTgamma Gene in Tomatoes

Hypertrophy development induced by the overexpression of SlbHLH22 (also called SlUPA-like) was susceptible to Xanthomonas in tomatoes. Transcriptome and metabolome analyses were performed on the hypertrophy leaves of a SlbHLH22-overexpressed line (OE) and wild type (WT) to investigate the molecular mechanism. Metabolome analysis revealed that six key metabolites were over-accumulated in the OE, including Acetylserine/O-Acetyl-L-serine, Glucono-1,5-lactone, Gluconate, 2-Oxoglutarate, and Loganate, implying that the OE plants increased salt or oxidant resistance under normal growth conditions. The RNA-seq analysis showed the changed expressions of downstream genes involved in high-energy consumption, photosynthesis, and transcription regulation in OE lines, and we hypothesized that these biological processes were related to the GTgamma subfamily of trihelix factors. The RT-PCR results showed that the expressions of the GTgamma genes in tomatoes, i.e., SlGT-7 and SlGT-36, were suppressed in the hypertrophy development. The expression of the GTgamma gene was downregulated by salinity, indicating a coordinated role of GTgamma in hypertrophy development and salt stress. Further research showed that both SlGT-7 and SlGT-36 were highly expressed in leaves and could be significantly induced by abscisic acid (ABA). The GTgamma protein had a putative phosphorylation site at S96. These results suggested GTgamma's role in hypertrophy development by increasing the salt resistance.

The spatial distribution and migration of three typical fungicides in postharvest satsuma mandarin (Citrus unshiu Marc.) fruit

Fungicides are often used to extend the storage time of postharvest satsuma mandarin fruit. In recent years, fungicide residue has become an issue of food safety. This study aimed to investigate the distribution and migration of three typical fungicides (imazalil, prochloraz, thiophanate-methyl) in postharvest satsuma mandarins using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Three fungicides could quickly penetrate satsuma mandarins and their gradient concentrations of residues in the fruit were: carpopodium > mesocarp > epicarp > pulp. However, the residues of three fungicides in the edible pulp were obviously lower than the maximum residue limit (MRL = 5.0 mg kg^-1 in China). Residues of the three fungicides decreased in epicarp and carpopodium but increased in mesocarp and pulp during storage. Fungicides could quickly penetrate the fruit, settling primarily in the carpopodium but little in the pulp. Both epicarp and carpopodium were the breakthrough pathways for the fungicides entering the fruit, while epicarp was the main route for the penetration of fungicides. These findings shed new information on the behavior of fungicides and the safety issue of satsuma mandarins.

The research progress in and perspective of potential fungicides: Succinate dehydrogenase inhibitors

Succinate dehydrogenase inhibitors (SDHIs) have become one of the fastest growing classes of new fungicides since entering the market, and have attracted increasing attention as a result of their unique structure, high activity and broad fungicidal spectrum. The mechanism of SDHIs is to inhibit the activity of succinate dehydrogenase, thereby affecting mitochondrial respiration and ultimately killing pathogenic fungi. At present, they have become popular varieties researched and developed by major pesticide companies in the world. In the review, we focused on the mechanism, the history, the representative varieties, structure-activity relationship and resistance of SDHIs. Finally, the potential directions for the development of SDHIs were discussed. It is hoped that this review can strengthen the individuals' understanding of SDHIs and provide some inspiration for the development of new fungicides.