What might be living inside plants?

Plants do not live alone. Some organisms tend to live inside the plants and are generally called endophytes. In their study, Potshangbam et al., have explored the fungal endophytes from two cereal crops- rice and maize. The authors have further tried to test the response of these endophytes to a number of harsh conditions.

Article: Potshangbam, M., Devi, S. I., Sahoo, D., & Strobel, G. A. (2017). Functional Characterization of Endophytic Fungal Community Associated with Oryza sativa L. and Zea mays L. Frontiers in microbiology8, 325. doi: 10.3389/fmicb.2017.00325


Understanding fungal endophytes in plants

Plants never live in isolation and are closely associated with different types of organisms. One such type of organism is the fungal endophyte. Although fungal endophytes live inside their host plants, they do not cause any damaging symptoms in these plants. Fungal endophytes occupy diverse parts of a particular plant such as the seeds, fruits, roots, stems and even leaves.

Figure1. Growth of four fungal colonies of Aspergillus (Source: AJ Hunter, distributed under CC BY-SA 3.0 license)

Do plants benefit from their partnership with the endophytes?

Until now scientists have reported a number of roles that the fungal endophytes may have on the plants with which they remain associated. The benefits to these host plants come in the form of protection against heat, drought, nutrient scarcity, high salinity in soil, grazing cattles as well as insects. Some endophytes help the plants to grow while some are said to defend their host plants against diseases as well. The credit for all these functions goes to bioactive compounds produced by fungal endophytes. These bioactive compounds vary according to their chemical composition as well as the types of endophytes and their host plants.

Studies of fungal endophytes

Many studies have revealed the various fungal endophytes which are present across diverse host plants. To name a few, Penicillium and Aspergillus are the endophytes of sunflower plants; Rhodotorula and Aspergillus partner with strawberries; Cladosporium reside in blueberries. Potshangbam et al. has carried out one of the important investigations on fungal endophytes of crop plants from a region in the Indo-Burma biodiversity hotspot.

Intimacy between the fungal endophytes and crop plants

The researchers wanted to explore the fungal endophytes that reside within the crop plants of rice and maize. Additionally, Potshangbam et al.  wanted to know if the endophytes have the potential to protect crop from stress and diseases and promote growth. They collected crop plants-rice and maize and cleaned their surfaces vigorously. The authors tried to isolate and identify the endophytes from different regions of the plants in a growth medium. They identified a total of 123 fungi residing in various parts of rice and maize, the most common being Penicillium, Aspergillus, Acremonium and Fusarium. With all these 123 isolated fungi, they further tested their ability to endure harsh conditions by creating an artificial environment such as acidic conditions, high salt concentrations and low plus high temperatures. They also examined whether the isolated fungal endophytes could defend the attack from other disease causing organisms of these crops. Different fungal endophytes showed diverse yet promising responses to the harsh conditions.

Figure3. Maize crops  (Source: Trish Steel, distributed under CC BY-SA 2.0 license)


Future directions

A particular plant houses more than a single fungus inside it. Besides, different types of fungi might be present in different plants. Although the plant endophytes have been explored, scientists are of the opinion that there is a lot more to explore: different types of fungi from different parts of the plants along with their different chemical compositions and functions!  The future focus is to also work on widening the field of applicability of these fungal endophytes.


Further reading:

Higginbotham, S. J., Arnold, A. E., Ibañez, A., Spadafora, C., Coley, P. D., & Kursar, T. A. (2013). Bioactivity of fungal endophytes as a function of endophyte taxonomy and the taxonomy and distribution of their host plants. PloS one8(9), e73192.

Hassan, S. E. D. (2017). Plant growth-promoting activities for bacterial and fungal endophytes isolated from medicinal plant of Teucrium polium L. Journal of advanced research8(6), 687-695.

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