Inhibition Of Citrus Acid Rot And Its Metabolites By Peppermint Essential Oil

Sour rot,caused by Geotri chumcitri-aurantii,is one of the most devastating diseases in citrus fruits,resulting in devastating crop losses worldwide.At present,chemical fungicides are still the main means of prevention and cure,However,most of the chemical fungicides have the problem of toxicity and residue,It is easy to cause serious harm to human health and environmental safety.Previous study found that peppermint,As a kind of natural plant source,was effective to control postharvest sour.Therefore,it is of great economic and social significance to use plant essential oil as an alternative to chemical fungicides for the control of pathogenic microorganisms.In this paper,plant oil and citrus acid bacteria as material,discussed the antibacterial mechanism of essential oil and as a biological elicitor on disease resistance of citrus fruit enhancement effect.Molecular biology and signaling pathways receptor competition/blocking technology were employed to reveal host cell changes in metabolic levels.The main findings were as follows:(1)Peppermint oil could significantly inhibit the development of G.citri-aurantii on Citrus,and positively correlated with concentration.What’s more,we found the minimal inhibitory concentration(MIC)is 0.4 μL/mL(2)By conductivity meter,analysis of the failure of peppermint oil on the cellular membrane of G.citri-aurantii.The results showed that peppermint oil could cause the cell membrane breakdown,Causing an imbalance in intracellular osmotic pressure,and the leakage of vital intracellular ingredients such as ions,amino acids,nucleic acids and ATP.Causing the conductivity of treatment group increased.(3)With the help of metabonomics technique,the two groups with different treatment were compared and analyzed.The results showed that 353 kinds of metabolites could be detected,and 53 substances changed significantly among them(|Fold Change |≥2).Including 16 kinds of fatty acids,6 kinds of sugars,2 kinds of amino acids,5 kinds of alcohols,2 kinds of glycosides,3 kinds of ketones and so on.These substances are mainly involved in 25 metabolic pathways,including glycolysis,tricarboxylic acid cycle(TCA),pentose phosphate pathway(PPP),amino acid metabolism,purine metabolism,pyrimidine metabolism,amino sugar,fatty acid biosynthesis,and cofactor metabolism.(4)When the citrus fruits treated with peppermint oil directly,we found that peppermint oil has a strong inhibition activity in controlling G.citri-aurantii.And when the oil concentration of 1.6μL/mL,it exhibited the greatest antifungal activity,reducing the disease incidence to 64%compared with the control.(5)Hyphenated techniques using chromatography mass spectrometry,metabolites of citrus peels were observed when treated with the spore suspension of G.citri-aurantii,peppermint oil and a combination of both.The results showed that peppermint oil could enhance the synthesis of a series of metabolites related to plant hormones,signal transduction,stress and defense responses in the host.These included 32 increased and 50decreased metabolite abundances.Furthermore,most of metabolites Involved in metabolic pathways,ABC transporters,Biosynthesis of secondary metabolites and phosphotransferase system.