Tomato is an economic crop worldwide. Many limiting factors reduce the production of tomato, with bacterial wilt caused by Ralstonia solanacearum being the most destructive disease. Our previous study showed that the disease resistance to bacterial soft rot is enhanced by Bacillus amyloliquefaciens strain PMB05. This enhanced resistance is associated with the intensification of pathogen-associated molecular patterns (PAMP)-triggered immunity (PTI). To determine whether the PTI-intensifying Bacillus spp. strains are able to confer disease resistance to bacterial wilt, their effects on PTI signals triggered by PAMP from R. solanacearum and on the occurrence of bacterial wilt were assayed. Before assay, a gene that encodes harpin from R. solanacearum, PopW, was applied as a PAMP. Results revealed that the B. amyloliquefaciens strain PMB05 was the one strain among 9 Bacillus rhizobacterial strains which could significantly intensify the PopW-induced hypersensitive response (HR) on Arabidopsis leaves. Moreover, we observed that the signals of PopW-induced reactive oxygen species generation and callose deposition were increased, confirming that the PTI was intensified by PMB05. The intensification of the PopW-triggered HR by PMB05 in Arabidopsis was reduced upon treatment with inhibitors in PTI pathways. Furthermore, the application of Bacillus spp. strains on tomato plants showed that only the use of PMB05 resulted in significantly increased resistance to bacterial wilt. Moreover, the PTI signals were also intensified in the tomato leaves. Taken together, we demonstrated that PMB05 is a PTI-intensifying bacterium that confers resistance to tomato bacterial wilt. Screening of plant immunity intensifying rhizobacteria is a possible strategy to control tomato bacterial wilt. [ ] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Banana is a typical tropical fruit that is widely cultivated in tropical and subtropical regions, and consumed daily because of its superior nutritional profile. This study aimed to investigate the changes in bananas’ physicochemical properties and nutritional composition from ripening stages 1 to 9. The analysis included color (peel and flesh), texture, total starch content, resistant starch content, free sugar content, minerals (calcium, magnesium, potassium, sodium, iron, phosphorus), and vitamin content. At the same time, the browning enzyme activities of polyphenol oxidase (PPO), peroxidase, oxalic acid, and tannin were also measured. In this study, the banana peel gradually changed from dark green to light green to yellow during the ripening process, eventually appearing with many black spots, while the pulp color changed from white to light yellow and decreased in brightness. The pulp became softer with a prolonged ripening period, which was inconsistent with the time point of peel color change (ripening period 4–5). However, total starch content decreased from 74% to 31%, resistant starch originally at 32% gradually decreased to 5%, and free sugar content gradually increased with increasing ripening period. Vitamin C content and PPO activity decreased significantly during the ripening period, while other vitamins and minerals did not change significantly. In contrast, oxalic acid, tannin content, and peroxidase activity were negatively correlated with the ripening period. Therefore, this study reveals the changes in the nutrient content of bananas at different ripening stages, which may provide helpful information for researchers and producers to identify suitable raw materials for producing stable and high-nutrition-value banana-related foods during the peak raw material abundance seasons while reducing business risk.

Anthracnose is a destructive postharvest disease of mango fruit, especially after ripening. The application of antagonistic Bacillus spp. strains is one of many promising control strategies. B. amyloliquefaciens (PMB04) exhibits strong antagonistic activity against anthracnose in strawberry fruit, yet has not been explored for anthracnose control in mango fruit. Among seven tested rhizobacterial strains, PMB04 exhibited the strongest inhibition against Colletotrichum gloeosporioides (Cg) growth. PMB04 demonstrated better inhibitory activity against Cg mycelial growth than the fungicides pyraclostrobin and difenoconazole. A PMB04 fermentation broth (PMB04FB) was prepared and tested, and showed superior efficacy in the reduction of anthracnose disease severity in mangoes compared to a PMB04 suspension, difenoconazole, or pyraclostrobin. We further found PMB04FB increased the mortality ratio of Cg conidia. Our study demonstrates that treatment with PMB04FB is an effective control method for anthracnose in mango and represents a promising strategy for postharvest mango processing.

Papaya (Carica papaya L.) is a typical climacteric fruit with a brief shelf life due to the rapid degradation of quality during post-ripening, necessitating appropriate postharvest management to address this challenge. This study aimed to investigate the characteristics of thyme oil nanoemulsion (TO-NE) coating and utilize its benefits for preserving papaya. This study also investigated the physiological properties and quality changes of papaya storage at 20 ℃ and, in parallel, examined the effects of TO-NE coating to mitigate microbial infection of papaya during storage. The postharvest papaya was soaked in different concentrations (0.1, 0.25, and 0.5 mg/g) of TO-NE for coating. At the same time, the decay loss rate and effective shelf life were also evaluated. This study revealed that polygalacturonase (PG) and pectinesterase (PME) activities were inhibited during the storage of papaya treated with 0.25 mg/g TO-NE coated compared to the control group. This resulted in the preservation of the firmness of papaya fruits, in addition to a higher ascorbic acid content, delayed total soluble solids (TSS) accumulation, and total chlorophyll content (TCC) degradation, with a lagging color change for two days. The respiration rate and ethylene production were suppressed, while the 0.25 mg/g TO-NE coated group at day 14 (ethylene peak) were 63.2 mg CO₂ kg⁻¹ h⁻¹ and 7.3 µL kg⁻¹ h⁻¹, lower than control. The 0.25 mg/g TO-NE coating treatment significantly reduced the decay rate for 10 days of storage, preserving their appearance and facilitating ripening. This is a viable option for extending Tainung No.2 papaya shelf life. Graphical Abstract

A kind of hydroxylated polymethoxyflavone (PMFs) existing in the citrus genus, 5-Demethyltangeretin (5-DTAN), has been reported to possess several bioactivities in vitro and in vivo. The aim of this study was to investigate whether acetylation could enhance the anticancer activity and oral bioavailability of 5-DTAN. PC-3 human prostate cancer cells were treated with tangeretin (TAN), 5-DTAN, and 5-acetylated TAN (5-ATAN), and the results showed that the cytotoxic effect 5-ATAN (IC₅₀ value of 5.1 µM) on the cell viability of PC-3 cells was stronger than that of TAN (IC₅₀ value of 17.2 µM) and 5-DTAN (IC₅₀ value of 11.8 µM). Compared to 5-DTAN, 5-ATAN treatment caused a more pronounced DNA ladder, increased the sub-G1 phase population, and induced G2/M phase arrest in the cell cycle of PC-3 cells. We also found that 5-ATAN triggered the activation of caspase-3 and the progression of the intrinsic mitochondrial pathway in PC-3 cells, suggesting the induction of apoptosis. In a cell wound healing test, 5-ATAN dose-dependently reduced the cell migration, and the expression of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) was decreased after 48 h of 5-ATAN treatment. Moreover, oral administration of 5-ATAN showed a significantly stronger inhibitory effect on tumor size and tumor weight in tumor-bearing nude mice than those of vehicle or the 5-DTAN group (p < 0.05). Furthermore, pharmacokinetic results showed that single-dose oral administration of 5-ATAN exhibited a higher maximum concentration (Cmax) and area under the curve (AUC) of 5-DTAN in plasma than that of 5-DTAN. More extensive distribution of 5-DTAN to most tissues of mice was also observed in mice treated with 5-ATAN for 7 days. In conclusion, acetylation strongly enhances the anticancer activity and oral bioavailability of 5-DTAN and could be a promising strategy to promote the potential bioactivities of natural products.

The limited cold tolerance of the Jin Huang mango represents a significant impediment to its potential for international trade. Therefore, this study evaluated the quality index changes of green maturity Jin Huang mangoes with different post-ripening treatments and then when stored at different storage periods (7, 14, 21, and 28) at 4 °C followed by 6 days at 20 °C. This study showed that the mangoes treated with 500 ppm ethylene were slow to ripen during 4 °C storage, which could be sustainable even under 20 °C storage. In addition, the control (CK) group failed to mature or ripen unevenly after storage at 4 °C. Moreover, the T3 group (ethylene ripening for 1 day and post-ripening at 20 °C for 1 day) minimized the occurrence of CI during storage compared to the CK group while contributing to a 30% decrease in anthracnose incidence and a decrease in firmness and titratable acid (TA), while total soluble solids (TSS) notably increased, yet the ascorbic acid content in this group was lower. Hence, the treatment conditions of Jin Huang mango using T3 helped extend its shelf-life at 20 °C, stocking and minimizing CI and anthracnose, thereby maintaining a certain quality.