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Anthracnose decay caused by Colletotrichum gloeosporioides greatly shortens the shelf life and commercial quality of mango fruit. Putrescine (1,4-Diaminobutane) is involved in modulating plant defense to various environmental stresses. In this research, in vivo and in vitro tests were used to explore the antifungal activity and the underlying mechanism of putrescine against C. gloeosporioides in mango fruit after harvested. In vivo tests suggested that putrescine markedly delayed the occurrence of disease and limited the spots expansion on inoculated mango fruit. Further analysis exhibited that putrescine treatment enhanced disease resistance, along with enhanced activities of chitinase (CHI), β-1,3-glucanase (GLU), phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), 4-coumarate coenzyme A ligase (4CL), polyphenol oxidase (PPO) and the accumulation of lignin, flavonoid, phenolics, and anthocyanin in infected mango fruit. In addition, in vitro tests showed that putrescine exerted strongly antifungal activity against C. gloeosporioides. Putrescine induced the production of reactive oxygen species (ROS) and severe lipid peroxidation damage in C. gloeosporioides mycelia, resulting in the leakage of soluble protein, soluble sugar, nucleic acids, K+ and Ca2+ of C. gloeosporioides mycelia. The mycelium treated with putrescine showed severe deformity and shrinkage, and even cracking. Taken together, putrescine could effectively reduce the incidence rate and severity of anthracnose disease possibly through direct fungicidal effect and indirect induced resistance mechanism, thus showing great potential to be applied to disease control. [Display omitted] • Putrescine enhanced anthracnose resistance in mango fruit. • Putrescine inhibited mycelial growth and spore germination of C. gloeosporioides. • Putrescine caused plasma membrane damage and leakage of intracellular constituents of C. gloeosporioides. • Putrescine enhanced defense-related enzyme activities and accumulation of antifungal compounds. [ABSTRACT FROM AUTHOR]

The effects and mechanisms of salicylic acid (SA) on defense response to Colletotrichum gloeosporioides from mango fruits were investigated by in vitro and in vivo test. In vitro experiment results showed that SA significantly reduced mycelial growth of C. gloeosporioides in a concentration-dependent manner. SA effectively controlled anthracnose decay on inoculated mango fruit, as well as natural infection. Disease incidence and lesion diameter in SA-treated fruit were significantly lower than those of the control fruit. SA treatment increased the activities of chitinase, β-1,3-glucanase, phenylalanine ammonia-lyase and polyphenoloxidase, and the content of total phenolic compounds and lignin in mango fruit. Moreover, SA treatment effectively maintained fruit firmness by suppressing conversion of insoluble protopectin into water soluble pectin. And correlation analysis showed there is a higher negative correlation between fruit firmness and disease incidence. These findings suggest that the effect of SA on postharvest diseases was attributed to its direct antimicrobial activity and the elicitation of resistant responses, as well maintaining the firmness in mango fruit. Therefore, SA treatment is a promising measure for controlling postharvest anthracnose rot in mango. Practical Applications Induction of fruit resistance against pathogenic infection with biological or chemical elicitors has been thought to be a promising approach for controlling of postharvest diseases and reducing the use of synthetic fungicides. Anthracnose, caused by Colletotrichum gloeosporioides is the predominant postharvest disease in mango production that causes severe postharvest losses and fruit quality deterioration. SA is a natural plant substance involved in plant defense responses to biotic stresses. The present results from in vitro and in vivo experiment suggested that SA treatment could effectively inhibit mycelial growth of C. gloeosporioides, enhance resistance of mango fruit against the pathogen and reduce anthracnose rot, as well maintain fruit firmness. Hence, SA can be applied in mango storage and preservation. [ABSTRACT FROM AUTHOR]

B Correction to: Environmental Science and Pollution Research b https://doi.org/10.1007/s11356-022-24225-9 The last 8 references of the article are in Chinese and should be changed to English. The original article can be found online at https://doi.org/10.1007/s11356-022-24225-9. [Extracted from the article]

• EBR enhanced anthracnose resistance in mango fruit. • EBR showed no antifungal activity to C. gloeosporioides in vitro. • EBR enhanced defense-related enzyme activities. • EBR slowed down the hydrolysis of pectin. Brassinosteroids (BRs) are natural steroidal phytohormones that regulate many essential processes of plant growth, development and responses to stress. However, the role of BRs in the defense response against Colletotrichum gloeosporioides in mango fruit remains largely unknown. This study investigated the resistance against C. gloeosporioides and the possible mechanisms of exogenous 24-epibrassinolide (EBR) in mango fruit. Results showed 1 μmol L−1 EBR effectively reduced the disease incidence and disease severity on mango fruit after inoculating with C. gloeosporioides. However, EBR had no direct antifungal activity against C. gloeosporioides in vitro test. EBR significantly improved the activities of phenylalanine ammonia-lyase (PAL), peroxidase (POD), chitinase (CHT), cinnamate-4-hydroxylase (C4H), β-1,3-glucanase (GLU) and 4-hydroxycinnamate CoA ligase (4CL), as well as the accumulation of flavonoids, lignin and total phenolics in mango fruit. EBR treatment also increased hydrogen peroxide (H 2 O 2) content in mango fruit at early storage stage after inoculation, while increased catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD) activities with low reactive oxygen species (ROS) level in later storage stage. Besides, EBR treatment markedly reduced the changes in pectin methylesterase (PME) and polygalacturonase (PG) activities, which slowed down the hydrolysis of pectin, thus maintaining cell wall integrity. The principal component analysis indicated that EBR treatment was strongly associated with the increase of defense enzyme activities and metabolite contents and the inhibition of pectin hydrolysis. These results indicated that exogenous EBR could be a promising strategy to increase resistance against C. gloeosporioides in mango fruit by improving the defense responses against pathogens. [Display omitted] [ABSTRACT FROM AUTHOR]