Colonization with non-mycorrhizal culturable endophytic fungi enhances orchid growth and indole acetic acid production
Date
2022Author
Shah, Sujit
Shah, Biva
Sharma, Rohit
Rekadwad, Bhagwan
Shouche, Yogesh S
Sharma, Jyotsna (TTU)
Pant, Bijaya
Metadata
Show full item recordAbstract
Background: Symbiotic associations of endophytic fungi have been proved by possessing an ability to produce
hormones and metabolites for their host plant. Members of the Orchidaceae are obligate mycorrhizal species but a
non-mycorrhizal association needs more investigation for their ability to promote plant growth and produce plant
growth hormones. In the present study, endophytic fungi were isolated from the roots of Dendrobium longicornu
Lindl., to investigate the root colonizing activity and role in plant growth and development.
Results: Among 23 fungal isolates were identifed both by morphological and molecular technique as Penicillium
sp., Fusarium sp., Coniochaeta sp., Alternaria sp., and Cladosporium sp. The dominate species were Coniochaeta sp. and
Cladosporium sp. The dominant species as per the isolation was Coniochaeta sp. These fungal strains were screened
for growth-promoting activity of Cymbidium aloifolium (plantlet) consider as cross genus interaction and Dendrobium longicornu (protocorms) as a host plant in in-vitro condition. Importantly, Cladosporium sp., and Coniochaeta sp.
showed successful colonization and peloton formation with roots of C. aloifolium. Moreover, it also enhanced acclimatization of plantlets. Fungal elicitors from nine fungal isolates enhanced the growth of the in vitro grown protocorms
of D. longicornu. Key bioactive compounds detected in the fungal colonized plant extract were 2H-pyran-2-one,
Cyclopropanecarboxylic acid, Oleic Acid and d-Mannitol, which may have a potential role in plant-microbe interaction. All fungal endophytes were able to synthesize the indole acetic acid (IAA) in presence of tryptophan. Moreover,
fungal extract DLCCR7 treated with DL-tryptophan yielded a greater IAA concentration of 43μg per ml than the other
extracts. The iaaM gene involved in IAA synthesis pathway was amplifed using iaaM gene primers successfully from
Alternaria sp., Cladosporium sp., and Coniochaeta sp.
Conclusions: Hence, this study confrms the production of IAA by endophytes and demonstrated their host as well
as cross-genus plant growth-promoting potential by producing metabolites required for the growth of the plant.