Piper nigrum Linnaeus is often used as a treatment for chills, stomach diseases, and other ailments. Piperine has many biological functions; however, its mechanism for preventing gastric mucosal damage is still unclear. The objective of this study was to investigate the preventive effects of piperine on ethanol-induced gastric mucosal injury by using GES-1 cells and rats. SOD, CAT, GSH-Px and MDA were effectively regulated in GES-1 cells pre-treated with piperine. Piperine significantly increased SOD, CAT and GSH-Px activities, but decreased the ulcer area, MDA, ROS and MPO levels in the gastric tissues of rats. RT-PCR analysis showed that piperine downregulated the mRNA expression levels of keap1, JNK, ERK and p38, and upregulated the mRNA transcription levels of Nrf2 and HO-1. Western blotting results indicated that piperine could activate the protein expression levels of Nrf2 and HO-1 and inhibit the protein expression levels of keap1, p-JNK, p-ERK and p-p38. In conclusion, piperine suppressed ethanol-induced gastric ulcers in vitro and in vivo via oxidation inhibition and improving gastric-protecting activity by regulating the Nrf2/HO-1 and MAPK signalling pathways.

Mallotus oblongifolius (MO), which is rich in polyphenols, is a characteristic tea resource with medicinal value. In this study, a total of 45 polyphenolic components of MO, including narirutin, isoquercitrin, rutin and digallic acid, were identified by UPLC-Q-TOF/MS analysis. In addition, the gastroprotective effect of Mallotus oblongifolius polyphenols (MOP) on ethanol-induced gastric mucosal injury in rats was investigated. The rats received anhydrous ethanol after continuous gavage of MOP or lansoprazole for one week. In addition, the macro- and micro-damage induced by ethanol in the gastric tissue was significantly reduced after MOP pretreatment for one week. Further analysis showed that MOP prevented ethanol-induced acute gastric mucosal injury by increasing the expression of antioxidant enzymes (SOD, CAT, GSH-Px) and decreasing the expression of reactive oxygen species (ROS), lipid oxidation product (MDA) and myeloperoxidase (MPO). Meanwhile, MOP inhibited the phosphorylation of p38/ERK/JNK and promoted the activation of the Nrf2 pathway. These results suggested that MOP may be a promising therapeutic target for the prevention of ethanol-induced gastric mucosal injury by improving oxidative stress, inhibiting the p38/ERK/JNK signaling pathways and activating Nrf2 expression.

Durio zibethinus Murr. is a tropical fruit crop of growing global importance, prized for its unique flavor and nutritional value. Yet only a narrow genetic base has been utilized in breeding efforts. We performed whole-genome resequencing of 114 diverse durian accessions collected in China, identifying over 39 million high-quality SNPs across the genome, revealing genome-wide patterns of diversity. Population structure analysis revealed three major genetic clusters, supported by PCA, phylogenetic analysis, and STRUCTURE modeling. Genome-wide scans identified candidate selective sweeps, and several genes potentially under selection. From the 114 accessions, we further identified a core collection of representative durian germplasms capturing the majority of the species’ genetic diversity. This subset includes both elite cultivars and genetically distinct individuals. Our study provides insights into the genetic diversity and population structure of cultivated durian. The defined core collection and genomic variation map establish a valuable resource for durian breeding and germplasm conservation. These findings will facilitate the identification of superior alleles for important traits and guide future durian improvement programs.

Pouteria caimito (Ruiz & Pav.) Radlk is a tropical fruit tree that is of high commercial value. It has been widely cultivated in Hainan Province of China since 2009, and planting has rapidly expanded. In March 2017, P. caimito seedlings in several nursery gardens of Haikou city were affected by a leaf spot disease with an incidence of up to 39%. The disease symptoms of irregular brown spots appeared on the edges of the leaves as small lesions, ranging from 0.2 to 0.3 cm × 0.3 to 0.4 cm in size, which later merged and gradually expanded to the middle of the leaves, resulting of coverage more than 60% area of the leaf surface. Interestingly, no similar disease symptoms on leaves of mature plants were observed. White or grayish-green fungal colonies were consistently isolated from infected spots after surface-sterilization and placed on potato dextrose agar (PDA) for 3 to 7 days. Conidia were cylindrical with blunt ends, some slightly curved, ranging from 10.4 to 16.7 μm (mean 13.3 μm) × 4.2 to 5.8 μm (mean 4.8 μm) (n=100) in size. Similar colonies were isolated from different infected leaf samples from other nursery gardens. To further identify these isolates, the internal transcribed spacer (ITS), actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), chitin synthase (CHS-1), calmodulin (CAL) and manganese-superoxide dismutase (SOD2) genes were amplified and sequenced using primers developed by Weir et al (2012). The nucleotide sequences were deposited in GenBank (GenBank accession nos. MF197434, MG196057, MG196058, MG196059, MG196060 and MG196061, respectively). The results of sequence analyses showed the isolate was highly similar to C. gloeosporioides (Penz.) Penz. & Sacc., about 99% homology with C. Gloeosporioides by comparing with the sequences of ITS (KM513611.1), ACT (KM604707.1), CHS (MF554857.1) and CAL (KP145359.1). Pathogenicity experiments were carried out by spraying a conidial suspension (105 CFU/ml) on three tender leaves of healthy P. caimito seedlings, and three seedlings sprayed with sterile water served as the control. The sprayed seedlings were incubated in a growth chamber at 20 to 25 ℃ of 90% relative humidity under natural daylight. The test was repeated five times. The symptoms of leaf spot disease developed on seedlings after six days, while on the negative control was asymptomatic. The same pathogen was re-isolated from the infected leaves fulfilling Koch’s postulates for proof of pathogenicity. According to morphological characteristics and molecular analysis, the fungal strain was identified as Colletotrichum gloeosporioides (Penz.) Penz. & Sacc.(Bailey et al. 1992). C. gloeosporioides could not only cause leaf spot disease on P. caimito, but also causes the same symptoms on citrus (Nar et al. 2004) and pepper (Manandhar et al. 1995), which are the important cash crops in Hainan. To our knowledge, this is the first report of leaf spot disease caused by Colletotrichum gloeosporioides on Pouteria caimito in China.

Mango is an economically vital tropical fruit, but commercial production is often compromised by unstable fruit development and inconsistent quality under conventional farming practices. Plant growth regulators (PGRs) are widely applied in mango production in Hainan Province and significantly influence fruit quality attributes, including fruit size, total soluble solids (TSSs), and titratable acidity (TA). This study aimed to elucidate the effects of PGRs on fruit enlargement and quality in ‘Guifei’ mango (Mangifera indica L.), identify the optimal PGR application regime, and preliminarily screen core indicators for mango fruit quality evaluation. A completely randomized design was adopted, with three mango trees per treatment as biological replicates. Different concentrations of thidiazuron (TDZ), gibberellic acid (GA₃), and 6-benzyladenine (6-BA) were sprayed individually or in combination on 8–10-year-old mango trees at 20, 35, and 50 days after full bloom. Fruit morphological characteristics and quality attributes were then determined. Coefficient of variation analysis, Pearson correlation analysis, and principal component analysis were used to screen core fruit quality evaluation indicators, and Duncan’s multiple-range test was applied for mean separation to distinguish statistically significant differences from merely numerical trends. Among the individual PGR treatments, 16 mg/L TDZ, 100 mg/L GA₃, and 100 mg/L 6-BA exhibited the most favorable balance between fruit enlargement and quality maintenance. Among the combined treatments, GA₃ (100 mg/L) + 6-BA (100 mg/L) + TDZ (16 mg/L) exhibited the best overall performance, effectively promoting fruit enlargement while maintaining relatively stable fruit quality. Four indicators, namely, average single fruit weight, TSS, TA, and vitamin C content, were preliminarily identified as core indicators for evaluating ‘Guifei’ mango fruit quality. These findings provide a scientific basis for optimizing PGR application regimes and evaluating fruit quality in high-quality ‘Guifei’ mango production in Hainan.