scholarly journals Developing Penicillium digitatum Management Strategies on Post-Harvest Citrus Fruits with Metabolic Components and Colonization of Bacillus subtilis L1-21

2022 ◽  
Vol 8 (1) ◽  
pp. 80
Author(s):  
Yongmei Li ◽  
Mengyuan Xia ◽  
Pengbo He ◽  
Qiaoming Yang ◽  
Yixin Wu ◽  
...  

Citrus is among the most important plants in the fruit industry severely infected with pathogens. Citrus green mold caused by Penicillium digitatum is one of the most devastating diseases during post-harvest stages of citrus fruit. In this study, a potential endophyte Bacillus subtilis L1-21, isolated from healthy citrus plants, was assessed for its biocontrol activity against the pathogen P. digitatum. Based on an in vitro crosstalk assay, we suggested that B. subtilis L1-21 inhibits the pathogen with an inhibition zone of 3.51 ± 0.08 cm. Biocontrol efficacy was highest for the fermented culture filtrate of B. subtilis L1-21. Additionally, using GC-MS analysis, 13 compounds were detected in the extract of this endophyte. The culture filtrate in Landy medium could enlarge and deform pathogen spores and prevent them from developing into normal mycelium. Accordingly, the Landy culture filtrate of B. subtilis L1-21 was stable in the temperature range of 4–90 °C and pH of 3–11. Further, MALDI-TOF-MS for B. subtilis L1-21 detected surfactin, fengycin, bacillaene and bacilysin as potential antifungal compounds. GFP-tagged B. subtilis L1-21 easily colonized in citrus fruit peel and pulp, suggesting its role in eliminating the fungal pathogen. Altogether, it is highly expected that the production of antifungal compounds, and the colonization potential of B. subtilis L1-21 are required against the post-harvest P. digitatum pathogen on citrus fruit.

Cancers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 867 ◽  
Author(s):  
Goh ◽  
Tan ◽  
Goh ◽  
Chan ◽  
Pusparajah ◽  
...  

The search for effective methods of cancer treatment and prevention has been a continuous effort since the disease was discovered. Recently, there has been increasing interest in exploring plants and fruits for molecules that may have potential as either adjuvants or as chemopreventive agents against cancer. One of the promising compounds under extensive research is nobiletin (NOB), a polymethoxyflavone (PMF) extracted exclusively from citrus peel. Not only does nobiletin itself exhibit anti-cancer properties, but its derivatives are also promising chemopreventive agents; examples of derivatives with anti-cancer activity include 3′-demethylnobiletin (3′-DMN), 4′-demethylnobiletin (4′-DMN), 3′,4′-didemethylnobiletin (3′,4′-DMN) and 5-demethylnobiletin (5-DMN). In vitro studies have demonstrated differential efficacies and mechanisms of NOB and its derivatives in inhibiting and killing of colon cancer cells. The chemopreventive potential of NOB has also been well demonstrated in several in vivo colon carcinogenesis animal models. NOB and its derivatives target multiple pathways in cancer progression and inhibit several of the hallmark features of colorectal cancer (CRC) pathophysiology, including arresting the cell cycle, inhibiting cell proliferation, inducing apoptosis, preventing tumour formation, reducing inflammatory effects and limiting angiogenesis. However, these substances have low oral bioavailability that limits their clinical utility, hence there have been numerous efforts exploring better drug delivery strategies for NOB and these are part of this review. We also reviewed data related to patents involving NOB to illustrate the extensiveness of each research area and its direction of commercialisation. Furthermore, this review also provides suggested directions for future research to advance NOB as the next promising candidate in CRC chemoprevention.


2020 ◽  
Vol 6 (4) ◽  
pp. 203
Author(s):  
Sandra Garrigues ◽  
Jose F. Marcos ◽  
Paloma Manzanares ◽  
Mónica Gandía

Antifungal proteins (AFPs) from ascomycete fungi could help the development of antimycotics. However, little is known about their biological role or functional interactions with other fungal biomolecules. We previously reported that AfpB from the postharvest pathogen Penicillium digitatum cannot be detected in the parental fungus yet is abundantly produced biotechnologically. While aiming to detect AfpB, we identified a conserved and novel small Secreted Cysteine-rich Anionic (Sca) protein, encoded by the gene PDIG_23520 from P. digitatum CECT 20796. The sca gene is expressed during culture and early during citrus fruit infection. Both null mutant (Δsca) and Sca overproducer (Scaop) strains show no phenotypic differences from the wild type. Sca is not antimicrobial but potentiates P. digitatum growth when added in high amounts and enhances the in vitro antifungal activity of AfpB. The Scaop strain shows increased incidence of infection in citrus fruit, similar to the addition of purified Sca to the wild-type inoculum. Sca compensates and overcomes the protective effect of AfpB and the antifungal protein PeAfpA from the apple pathogen Penicillium expansum in fruit inoculations. Our study shows that Sca is a novel protein that enhances the growth and virulence of its parental fungus and modulates the activity of AFPs.


2003 ◽  
Vol 49 (4) ◽  
pp. 253-262 ◽  
Author(s):  
Yiu-Kwok Chan ◽  
Wayne A McCormick ◽  
Keith A Seifert

Bacteria were isolated from a cultivated soil and screened for antagonistic activity against Fusarium graminearum, a predominant agent of ear rot and head blight in cereal crops. Based on its in vitro effectiveness, isolate D1/2 was selected for characterization and identified as a strain of Bacillus subtilis by phenotypic tests and comparative analysis of its 16S ribosomal RNA gene (rDNA) sequence. It inhibited the mycelial growth of a collection of common fungal phytopathogens, including eight Fusarium species, three other ascomycetes, and one basidiomycete. The cell-free culture filtrate of D1/2 at different dilutions was active against macroconidium germination and hyphal growth of F. graminearum, depending on the initial macroconidium density. It induced the formation of swollen hyphal cells in liquid cultures of this fungus grown from macroconidia. A bioassay also demonstrated that D1/2 offered in planta protection against the damping-off disease in alfalfa seedlings caused by F. graminearum, while the type strain of B. subtilis was ineffective. Hence, B. subtilis D1/2 or its culture filtrate has potential application in controlling plant diseases caused by Fusarium.Key words: antifungal activity, Bacillus subtilis, biological control, biopesticide, Fusarium species.


2021 ◽  
Vol 12 ◽  
Author(s):  
Paco Romero ◽  
Maria Teresa Lafuente ◽  
Fernando Alferez

Water stress is the most important environmental agent that contributes to the crop productivity and quality losses globally. In citrus, water stress is the main driver of the fruit peel disorders that impact the quality and market ability. An increasingly present post-harvest peel disorder is non-chilling peel pitting (NCPP). Non-chilling peel pitting is manifested as collapsed areas of flavedo randomly scattered on the fruit and its incidence increases due to abrupt increases in the environmental relative humidity (RH) during post-harvest fruit manipulation. In this study, we have used a custom-made cDNA microarray containing 44k unigenes from Citrus sinensis (L. Osbeck), covering for the first time the whole genome from this species, to study transcriptomic responses of mature citrus fruit to water stress. In the study, the global gene expression profiles of flavedo from Navelate oranges subjected to severe water stress are compared with those fruits subjected to rehydration stress provoked by changes in the RH during post-harvest, which enhances the development of NCPP. The study results show that NCPP is a complex physiological process that shares molecular responses with those from prolonged dehydration in fruit, but the damage associated with NCPP may be explained by unique features of rehydration stress at the molecular level, such as membrane disorganization, cell wall modification, and proteolysis.


2020 ◽  
Vol 8 (2) ◽  
pp. 70-74
Author(s):  
Andhini Ardi ◽  
Dedi Sumantri ◽  
Surma Adnan

Enterococcus faecalis is a bacteria that commonly found in secondary root canal infections. Enterococcus faecalis is a gram-positive, facultative anaerobic bacteria. Langsat (Lansium parasiticum) is a natural ingredient that contains secondary metabolites and has antibacterial ativity. The aim of this study was to examine the inhibition effect of langsat fruit peel extract (Lansium parasiticum) to the growth of Enterococcus faecalis. This was a laboratory experimental study with post-only control group design. Langsat fruit peel extract with 25%, 50%, 75%, and 100% concentration was using disc diffusion method on Mueller-Hinton Agar (MHA) and the inhibition zone was measured with a sliding caliper. The data were analyzed with Kruskal-Wallis test and Mann-Whithney test. The result of this study was langsat fruit peel extract with 25%, 50%, 75% concentration showed a inhibition zone, while at 100% showed no inhibition zone. The Kruskal-Wallis test showed that there are significant differences (p <0.05) between all groups. The conclusion was langsat fruit peel extract (Lansium parasiticum) have weak inhibition effect of the growth of Enterococcus faecalis bacteria. The inhibition zone of concentrations 25% : 2,20 mm;  50%: 0,94 mm; 75%: 0,36 mm and 100% : 0,00 mm.


2022 ◽  
Author(s):  
Amna Kamal ◽  
Muhammad Adnan Iqbal ◽  
Haq Nawaz Bhatti ◽  
Abdul Ghaffar

Abstract N-heterocyclic carbene salts bearing alkyl substituents (1-8) and their selenium N-heterocyclic carbene adducts (9-12) were synthesized and characterized by elemental analysis, FT-IR, NMR (1HNMR, 13CNMR) spectroscopic techniques. All the adducts were found to be stable in air and moisture at room temperature. Compounds (5-12) were evaluated against Bacillus subtilis Macrococcus brunensis and Bacillus cereus in vitro. The biological assay revealed that antibacterial activity of Selenium-N-heterocyclic carbene adducts are comparatively better than the salts. MIC and inhibition zone values showed that Bacillus subtilis is more active to selenium adducts (9-12) than Macrococcus brunensis and Bacillus cereus whereas opposite in the salts (5-8). In vitro studies of hemolysis and thrombolysis demonstrated that the synthesized compounds are innocuous for pre-clinical trials to mouse blood.


2013 ◽  
Vol 35 (2) ◽  
pp. 425-436 ◽  
Author(s):  
Katia Cristina Kupper ◽  
Antonio Lucas Lima Cervantes ◽  
Mariana Nadjara Klein ◽  
Aline Caroline da Silva

Os frutos cítricos são afetados por diversas doenças, especialmente as fúngicas, as quais afetam a produtividade e a qualidade, principalmente quando se visa ao mercado de frutas frescas, seja para o mercado interno, seja para a exportação. Dentre as doenças fúngicas que ocorrem na fase de pós-colheita, destaca-se o bolor verde, causado por Penicillium digitatum. As medidas de controle baseiam-se, principalmente, no tratamento de frutos com diferentes combinações de fungicidas no packing-house. Devido às restrições quanto à presença de resíduos de fungicidas em frutos de citros e ao crescente desenvolvimento de linhagens resistentes dos patógenos a tais fungicidas, torna-se necessária a busca de alternativas de controle, como o controle biológico. Portanto, este trabalho teve por objetivos: (i) verificar o efeito antagônico de agentes de controle biológico (ACBs), sendo 06 isolados de Saccharomyces cerevisiae e 13 isolados de Bacillus subtilis contra P. digitatum; (ii) estudar as interações in vitro entre ACBs e o fitopatógeno; (iii) verificar o efeito da integração dos antagonistas com bicarbonato de sódio e cera de carnaúba no controle do bolor verde. Os resultados mostraram que a maioria dos isolados bacterianos e todos os isolados de levedura inibiram o crescimento micelial do fitopatógeno. Somente um isolado de Bacillus subtilis (ACB-84) foi capaz de inibir a germinação de P. digitatum com 72% de inibição, enquanto ACB-K1 e ACB-CR1 (S. cerevisiae) foram os mais eficientes com inibições de 78 e 85,7%, respectivamente; a adição de sacarose (a 0,5%) favoreceu ainda mais a inibição da germinação dos conídios pelos isolados da levedura. Os resultados de controle in vivo mostraram a viabilidade de S. cerevisiae ACB-K1 e ACB-CR1 para o controle de P. digitatum, em frutos de lima-ácida 'Tahiti' e laranja 'Hamlin', respectivamente; a associação de bicarbonato de sódio com agentes de biocontrole não resultou em melhorias no controle curativo do bolor verde; cera de carnaúba (18% de SST) favoreceu a atividade antagonística de S. cerevisiae, e tal efeito dependeu da variedade dos frutos cítricos em estudo e do isolado da levedura utilizado para o biocontrole.


2017 ◽  
Vol 53 (No. 3) ◽  
pp. 134-143 ◽  
Author(s):  
Mohammadi Parisa ◽  
Tozlu Elif ◽  
Kotan Recep ◽  
Kotan Merve Şenol

Ten bacteria isolate (4 Bacillus subtilis, 2 Bacillus pumilus, 2 Bacillus cereus, 1 Bacillus megaterium, and 1 Agrobacterium radiobacter) were tested in vitro for antagonistic properties against Penicillium digitatum, the causal agent of citrus green mould. The effect of these bacteria was also observed on mycelial growth, spore germination, and spore production of the pathogenic fungus in broth culture. Extracellular enzyme activities of the bacteria were determined. According to the results of in vitro antagonistic tests and enzymes activities, the most promising bacteria were Bacillus subtilis and Agrobacterium radiobacter. These bacteria were tested for disease suppression on lemon fruits. In addition, these bacterial isolates also showed remarkable antifungal activity against the pathogen on lemon fruits. The results of this study showed that Bacillus subtilis and Agrobacterium radiobacter showed remarkable antifungal activity against the pathogen. Chitinase and glucanase enzyme activity of all the tested bacteria was positive. Protease enzyme activity was positive in all tested bacteria with the exception of Agrobacterium radiobacter. In addition, all bacteria inhibited mycelial growth and spore germination (except Agrobacterium radiobacter) of the fungus. Bacillus subtilis, Bacillus cereus, and Agrobacterium radiobacter inhibited spore production in broth culture. Bacillus subtilis and Agrobacterium radiobacter were tested on lemon fruits significantly reduced disease severity. Consequently, these isolates can be used as new biocontrol agents in controlling the post-harvest decay of citrus fruits caused by Penicillium digitatum.


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