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Antagonistic Microbes

Myself Mubbara Arshad. I have done research specialization in the field of biopesticides and prepare them by using antagonistic microbes.

Overview of Antagonistic microbes

As we all know about microbes and microbial cultures, most of us know microbes as non-beneficial entities. But the maximum community of microbes is beneficial for many aspects. One of these aspects is antagonism. Antagonistic microbes are those who fight against microbes i.e. pathogenic microbes. Pathogenic microbes are not beneficial to plants. They destroy vegetable plants and also negatively affect their yield. Antagonist comes from a Greek word "Antagonistae" whose meaning is competitor. This word is derived from two other words "anti-" meaning against and "agonizesthai" meaning to contend for a prize. Hence antagonistic microbes are those who fights with pathogenic microbe in their host plant. In this article, the antagonistic microbes are discussed i.e. fungi and bacteria. there are many fungal species that serves as antagonist but the highly among all is Trichoderma sp. this is green colored fungal specie considering spores with a circular colony shape. This specie is grown at PDA potato dextrose agar at 25-28 Celsius temperature. This species consist of special metabolites that can fight with various plant pathogens and provide protection to plant. This specie not only fight with the pathogen but can also enhance the growth parameters and physiological parameters of plant. Resulting in maximum yield. There are various bacterial isolates that can also serves as antagonist but among all the best one studied is Bacillus subtilis and Pseudomonas fluorescens. These bacterial isolates are also have metabolites and enzymes that allow them to show antagonism potential against pathogen. They also fight with pathogen as well as enhance the yield of plant specie. So, this is the general or basic overview of antagonistic microbes that I know. In my next article I will share the detail about antagonistic microbes and their mode of action in plants against pathogen.

Fungi as Antagonistic microbes

There are large number of some specific species of fungi are biologically and systematically serves as a inhibitor for other pathogens. The most specific species that show antagonism includes the genus Trichoderma, Penicillium (Alam et al. 2010), Gliocladium (Agarwal et al. 2011), Aspergillus (Adebola and Amadi 2010), Saccharomyces (Nally et al. 2012), against few plant fungal pathogens which includes Alternaria, Pythium, Aspergillus, Fusarium, Rhizoctonia, Phytophthora, Botrytis, Pyricularia and Gaeumannomyces (Tariq et al., 2020). Trichoderma is a significant biocontrol agent and act as a micoparasite against the range of many soil and air-borne plant pathogen (Silva et al. 2017). Aspergillus, Alternaria, Fusarium and Penicillium, produce many kinds of mycotoxins which are harmful for leafy foods and cause post-harvest disease. Different mycotoxins i.e. aflatoxins, ochratoxins, alternaria and fumonisin, are released in fruits and vegetables that are contaminated with Aspergillus, Alternaria and Fusarium (Sanzani et al. 2016). The biocontrol capability was practically identical to that of the other fungicide in a sustainable way that is not harmful to the environment.

Bacteria as Antagonistic microbes

From many years ago, Bacteria have been used into soil, seeds, root and other parts of plants to improve its advancement and development. Nowadays, many bacterial species are being used and tried as antagonistic microbes, including Acinetobacter, Agrobacterium, Alcaligenes, Arthrobacter, Azospirillum, Azotobacter, Bacillus, Bradyrhizobium, Frankia, Pantoea, Pseudomonas, Rhizobium, Serratia, Stenotrophomonas, Streptomyces and Thiobacillus (Tariq et al., 2020). Bacillus specie is the best to control plant diseases in a wide range of crops including rice, wheat, potato, brinjal, tomato, chickpea, groundnut and cucumber (Peng et al. 2014). Kim et al. (2013) demonstrated that an isolated Bacillus sp. BS061 inhibited the mycelia development and significantly decrease the disease incidence of grey mould and powdery mildew in cucumber and strawberry. Most of the soilborne pathogens like root rot and root knot caused diseases in crop plants. Pseudomonas is commonly used to suppress the infection of root knot and root rot pathogens (Habiba et al. 2016). The antifungal activity of rhizobial isolates against some common plant pathogens, Macrophomina phaseolina, Rhizoctonia solani, Fusarium oxysporum and F. solani in mungbean crop demonstrated by Farhar et al., 2017. Jisha et al. (2018) examined the application of bacterial biocontrol agents Pseudomonas aeruginosa against the pathogen Colletotrichum capsici which cause anthracnose and systematic resistance against anthracnose on chilli plant (Tariq et al 2020).


Conclusion

Hence the above mentioned microbial species act as potential antagonistic microbes. These microbes not only fight with pathogen also enhance the growth of plant. That result in increasing the number of fruit and enhancing the quality of fruit at last.

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