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A. Ghasemnezhad et al.
endophytes, are also common inhabitants of the rhizosphere. Therefore, it has
been suggested that the endophyte microbiome may be a sub-population of the
rhizosphere inhabiting bacteria (Marquez-Santacruz et al. 2010). The genus Pseudomonas is ubiquitous in nature and part of the core endo-microbiome of many
plants ranging from model plants like Arabidopsis thaliana to medicinal plants like
Cannabis sativa. Pseudomonas sp. can confer unique characteristics to the host
plant and are well known for plant (Purushotham et al. 2020). More than 300 endophytic actinobacteria and bacteria belonging to the genera Streptomyces, Nocardiopsis, Brevibacterium, Microbacterium, Tsukamurella, Arthrobacter, Brachybacterium, Nocardia, Rhodococcus, Kocuria, Nocardioides, Pseudonocardia etc., were
isolated from different tissues of Dracaena cochinchinensis Lour. (a traditional
Chinese medicine known as dragon’s blood). Of these, 17 strains having antimicrobial and anthracyclines-producing activities also showed antifungal and cytotoxic activities against two human cancer cell lines, MCF-7 and Hep G2 (Salam
et al. 2017). The majority of endophytic bacteria produce different kinds of antibiotics. Ecomycin, pseudomycins, and kakadumycins are some of the novel antibiotics
produced by endophytic bacteria (Christina et al. 2013).
6.7 Interactions of Endophytes and the Host Plant
Importantly, similar to any other living organism, plants are flexible and can adapt
themselves and integrate with a different environment by strategically facing external
stresses. For instance, the healthy growth and complex adaptive response of plants,
often categorized as an intelligent response by a few authors (Chamovitz 2018), is
associated with this world of microbes. It is intriguing to note that even after 500
million years of evolution, plants still need the assistance of the endophytic community to be able to resist stress tolerance including climate change and adapt themselves
to their continuously changing environments (Deng and Cao 2017). This adaptation
behavior is directly buttressed by the production of bioactive compounds known
as secondary metabolites (Singh 2019). The endophytes survive on the nutrients
produced by the plants and in return, these endophytes yield functional metabolites for their host plants. There is a positive linear relationship between endophytes and their host plants in terms of the production of these bioactive compounds
(Palanichamy et al. 2018). Since endophytic fungal elicitors belong to extracellular
materials and cannot directly enter the cell to play a role, the process of endophytic fungal elicitors to influence the secondary metabolism of plant cells through
signal pathways will first identify and bind to the plant specific receptors on the cell
membrane, change the structure of the cell to promote the production of specialized intracellular messenger substances. These messenger substances can regulate
the expression of related genes in the nucleus through a series of signal transduction pathways. Finally, the defensive secondary metabolic system is activated, and
the synthesis of secondary metabolites (Yan et al. 2020). Hernández-Soberano et al.
A. Ghasemnezhad et al.
endophytes, are also common inhabitants of the rhizosphere. Therefore, it has
been suggested that the endophyte microbiome may be a sub-population of the
rhizosphere inhabiting bacteria (Marquez-Santacruz et al. 2010). The genus Pseudomonas is ubiquitous in nature and part of the core endo-microbiome of many
plants ranging from model plants like Arabidopsis thaliana to medicinal plants like
Cannabis sativa. Pseudomonas sp. can confer unique characteristics to the host
plant and are well known for plant (Purushotham et al. 2020). More than 300 endophytic actinobacteria and bacteria belonging to the genera Streptomyces, Nocardiopsis, Brevibacterium, Microbacterium, Tsukamurella, Arthrobacter, Brachybacterium, Nocardia, Rhodococcus, Kocuria, Nocardioides, Pseudonocardia etc., were
isolated from different tissues of Dracaena cochinchinensis Lour. (a traditional
Chinese medicine known as dragon’s blood). Of these, 17 strains having antimicrobial and anthracyclines-producing activities also showed antifungal and cytotoxic activities against two human cancer cell lines, MCF-7 and Hep G2 (Salam
et al. 2017). The majority of endophytic bacteria produce different kinds of antibiotics. Ecomycin, pseudomycins, and kakadumycins are some of the novel antibiotics
produced by endophytic bacteria (Christina et al. 2013).
6.7 Interactions of Endophytes and the Host Plant
Importantly, similar to any other living organism, plants are flexible and can adapt
themselves and integrate with a different environment by strategically facing external
stresses. For instance, the healthy growth and complex adaptive response of plants,
often categorized as an intelligent response by a few authors (Chamovitz 2018), is
associated with this world of microbes. It is intriguing to note that even after 500
million years of evolution, plants still need the assistance of the endophytic community to be able to resist stress tolerance including climate change and adapt themselves
to their continuously changing environments (Deng and Cao 2017). This adaptation
behavior is directly buttressed by the production of bioactive compounds known
as secondary metabolites (Singh 2019). The endophytes survive on the nutrients
produced by the plants and in return, these endophytes yield functional metabolites for their host plants. There is a positive linear relationship between endophytes and their host plants in terms of the production of these bioactive compounds
(Palanichamy et al. 2018). Since endophytic fungal elicitors belong to extracellular
materials and cannot directly enter the cell to play a role, the process of endophytic fungal elicitors to influence the secondary metabolism of plant cells through
signal pathways will first identify and bind to the plant specific receptors on the cell
membrane, change the structure of the cell to promote the production of specialized intracellular messenger substances. These messenger substances can regulate
the expression of related genes in the nucleus through a series of signal transduction pathways. Finally, the defensive secondary metabolic system is activated, and
the synthesis of secondary metabolites (Yan et al. 2020). Hernández-Soberano et al.