Multiomics analysis reveals that peach gum colouring reflects plant defense responses against pathogenic fungi

Rhizosphere Bacteria Help to Compensate for Pesticide-Induced Stress in Plants

Although exogenous chemicals frequently exhibit a biphasic response in regulating plant growth, characterized by low-dose stimulation and high-dose inhibition, the underlying mechanisms remain elusive. This study demonstrates, for the first time, the compensatory function of rhizosphere microbiota in assisting plants to withstand pesticide stress. It was observed that pak choi plants, in response to foliar-spraying imidacloprid at both low and high doses, could increase the total number of rhizosphere bacteria and enrich numerous beneficial bacteria. These bacteria have capabilities for promoting plant growth and degrading the pesticide, such as Nocardioides, Brevundimonas, and Sphingomonas. The beneficial bacterial communities were recruited by stressed plants through increasing the release of primary metabolites in root exudates, such as amino acids, fatty acids, and lysophosphatidylcholines. At low doses of pesticide application, the microbial compensatory effect overcame pesticide stress, leading to plant growth promotion. However, with high doses of pesticide application, the microbial compensatory effect was insufficient to counteract pesticide stress, resulting in plant growth inhibition. These findings pave the way for designing improved pesticide application strategies and contribute to a better understanding of how rhizosphere microbiota can be used as an eco-friendly approach to mitigate chemical-induced stress in crops.

Preparation and characterization of peach gum/chitosan polyelectrolyte composite films with dual cross-linking networks for antibacterial packaging

Peach gum (PG) is a valuable polymeric feedstock for developing eco-friendly, bio-safe, and functional materials. However, PG has limited use in food packaging due to its inferior mechanical and antibacterial properties. To overcome these limitations, we created a dual cross-linked network by introducing chitosan (CS) and glycerol to the PG matrix. Our research discovered that incorporating CS into the PG matrix significantly improved its Young's modulus, from 277.62 to 925.89 MPa, and its tensile strength from 5.96 to 39.94 MPa. Furthermore, the inclusion of glycerol greatly increased the elongation. These enhancements were attributed to the ionic and hydrogen-bonding interactions between the two biopolymers. Additionally, the composite films exhibited strong antibacterial effects, reducing the total number of colonies by 99.2 % and 99.9 % against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively. The incorporation of CS resulted in more amorphous films, enhancing their stiffness, flexibility, and barrier properties. To assess the practical application of PG/CS composite films, we conducted a comparative analysis between non-packaged strawberries and strawberries packaged with these films. The results demonstrated that the composite polyelectrolyte film extended the shelf life of strawberries better than the non-packaged fruits.

Polysaccharides from exudate gums of plants and interactions with the intestinal microbiota: A review of vegetal biopolymers and prediction of their prebiotic potential

Polysaccharides in plant-exuded gums are complex biopolymers consisting of a wide range of structural variability (linkages, monosaccharide composition, substituents, conformation, chain length and branching). The structural features of polysaccharides confer the ability to be exploited in different industrial sectors and applications involving biological systems. Moreover, these characteristics are attributed to a direct relationship in the process of polysaccharide enzymatic degradation by the fermentative action in the gut microbiota, through intrinsic interactions connecting bacterial metabolism and the production of various metabolites that are associated with regulatory effects on the host homeostasis system. Molecular docking analysis between bacterial target proteins and arabinogalactan-type polysaccharide obtained from gum arabic allowed the identification of intermolecular interactions provided bacterial enzymatic mechanism for the degradation of several arabinogalactan monosaccharide chains, as a model for the study and prediction of potential fermentable polysaccharide. This review discusses the main structural characteristics of polysaccharides from exudate gums of plants and their interactions with the intestinal microbiota.

Foliar Spraying of Chlorpyrifos Triggers Plant Production of Linolenic Acid Recruiting Rhizosphere Bacterial Sphingomonas sp

Plants have developed an adaptive strategy for coping with biotic or abiotic stress by recruiting specific microorganisms from the soil pool. Recent studies have shown that the foliar spraying of pesticides causes oxidative stress in plants and leads to changes in the rhizosphere microbiota, but the mechanisms by which these microbiota change and rebuild remain unclear. Herein, we provide for the first-time concrete evidence that rice plants respond to the stress of application of the insecticide chlorpyrifos (CP) by enhancing the release of amino acids, lipids, and nucleotides in root exudates, leading to a shift in rhizosphere bacterial community composition and a strong enrichment of the genus Sphingomonas sp. In order to investigate the underlying mechanisms, we isolated a Sphingomonas representative isolate and demonstrated that it is both attracted by and able to consume linolenic acid, one of the root exudates overproduced after pesticide application. We further show that this strain selectively colonizes roots of treated plants and alleviates pesticide stress by degrading CP and releasing plant-beneficial metabolites. These results indicate a feedback loop between plants and their associated microbiota allowing to respond to pesticide-induced stress.

Replacement of polyethylene oxide by peach gum to produce an active film using Litsea cubeba essential oil and its application in beef

This study evaluated the effects of adding various concentrations (0 %, 1 %, 2 %, and 3 %) of peach gum (PG) to films made from polyethylene oxide (PEO) combined with Litsea cubeba essential oil (LCEO) to be utilized as active packaging for food in the future. The findings showed that the film containing PG 2 % concentration had the best physic-mechanical properties. In films made with PG, the glass transition temperature was significantly improved. Combining PG and PEO resulted in films that were brighter in color, had lower WVP values, and had the lowest water activity. Furthermore, XRD demonstrated that PG additions were compatible with the film of PEO blended with LCEO. The PG films formulated with PG presented high antioxidant and antibacterial activity against Staphylococcus aureus and E. coli. Wrapping beef with P2G2 film led to maintaining its quality with suitable levels of pH, TBARS, and TVB-N. This also decreased the number of E. coli and S. aureus in beef throughout the storage period. The results indicate that adding PG to PEO films enhances their suitability for food preservation.

Optimization of Ultrasound- and Microwave-Assisted Extraction for the Determination of Phenolic Compounds in Peach Byproducts Using Experimental Design and Liquid Chromatography-Tandem Mass Spectrometry

The conversion of plant byproducts, which are phenolic-rich substrates, to valuable co-products by implementing non-conventional extraction techniques is the need of the hour. In the current study, ultrasound- (UAE) and microwave-assisted extraction (MAE) were applied for the recovery of polyphenols from peach byproducts. Two-level screening and Box-Behnken design were adopted to optimize extraction efficiency in terms of total phenolic content (TPC). Methanol:water 4:1% v/v was the extraction solvent. The optimal conditions of UAE were 15 min, 8 s ON-5 s OFF, and 35 mL g^-1, while MAE was maximized at 20 min, 58 °C, and 16 mL g^-1. Regarding the extracts' TPC and antioxidant activity, MAE emerged as the method of choice, whilst their antiradical activity was similar in both techniques. Furthermore, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to determine chlorogenic acid and naringenin in byproducts' extracts. 4-Chloro-4'-hydroxybenzophenone is proposed as a new internal standard in LC-MS/MS analysis in foods and byproducts. Chlorogenic acid was extracted in higher yields when UAE was used, while MAE favored the extraction of the flavonoid compound, naringenin. To conclude, non-conventional extraction could be considered as an efficient and fast alternative for the recovery of bioactive compounds from plant matrices.

Changes in Microbial Community Structure in Response to Gummosis in Peach Tree Bark

Peach gummosis disease has been identified as a serious challenge in Korean agriculture and has developed to become a major cause of agricultural productivity losses. However, treatments for gummosis have not been systemically established and studies of the microbiome closely related to this plant disease are lacking. Therefore, we analyzed the bacterial and fungal communities in the bark and rhizosphere soil of healthy peach trees and those with gummosis. Through high-throughput sequencing, we obtained unprecedented insights into the bacterial and fungal dynamics of each group, including their diversity and taxonomic classification, as well as network analyses. We found that the presence of gummosis drives a significantly higher alpha diversity in the bark bacterial community. Peach gummosis bark mycobiomes included greater numbers of opportunistic pathogens such as Ascochyta, Botryosphaeria, Saccharomyces, Nectriaceae_NA, Trametes, and Valsaceae_NA. However, the microbiome also included bacteria beneficial to plant growth and the production of polysaccharides-namely, 1174-901-12, Catenibacterium, Cutibacterium, Friedmanniella, Methylobacterium-Methylorubrum, Pseudomonas, Rhodobacter, and Sphingomonas. Furthermore, we confirmed that gummosis induced a more complex structure in the bark microbiome network. We conclude that the findings of this study provide a valuable aid in profiling the overall peach tree microbial ecosystem, which can be utilized to develop precise biomarkers for the early diagnosis of gummosis.

Comparative metabolomics analysis of pericarp from four varieties of Zanthoxylum bungeanum Maxim

A qualitative and quantitative analysis of metabolites was performed by metabolomics comparation on the pericarps of four varieties of Zanthoxylum bungeanum Maxim. The Zanthoxylum bunganum as scion combined with three rootstock varieties of Zanthoxylum piasezkii Maxim (YJ), July Zanthoxylum bunganum Maxim (QJ), and August Zanthoxylum bunganum Maxim (BJ), at the same time Zanthoxylum bungeanum seedlings breeding were compared as control (MJ). A total of 1429 metabolites were identified in Zanthoxylum bungeanum Maxim pericarps based on chromatography and mass spectrometry dual detection platform. While the metabolites between four varieties of Z. bungeanum varied, there was identified 31, 15, 7, 79, 42, 19 down-regulated and 55, 50, 13, 75, 43, 27 up-regulated differential metabolites between MJ and BJ, MJ and QJ, MJ and YJ, QJ and BJ, YJ and BJ, YJ and QJ. Meanwhile, the differential metabolites composition was distinct among various varieties of Z. bungeanum and dominant by phenolic compounds flavonoid and phenolic acids, especially highest in varieties July Zanthoxylum bunganum Maxim. Highlight A comparative metabolomics analyzed in four varieties of Zanthoxylum bungeanum pericarp.Total 1429 metabolites were identified and mainly in flavonoid and phenolic acid.July and August Zanthoxylum bunganum Maxim has highest antioxidant capacity.The rootstock July Zanthoxylum bunganum Maxim was recommended in Loess Plateau.