Evaluation of Plant Growth Promoting Production from Endophytic Fungi Isolated from Forage Grass and Grass Weed on in vitro propagation of Paphiopedilum callosum (Rchb.f.) Stein

Abstract

Microorganisms known as endophytes inhabit plant tissues produce bioactive secondary metabolites, some of which stimulate plant growth. The objective of this research was to screen plant growth-promoting endophytic fungi isolated from the leaves, stems, and roots of Guinea grass (Panicum maximum Jacq.), Napier grass (Pennisetum purpureum Schumach.), Ruzi grass (Brachiaria ruziziensis R.Germ.), Para grass (Brachiaria mutica (Forsk.) Stapt), Pangola grass (Digitaria eriantha Steud.), and weed species such as Crowfoot grass (Dactyloctenium aegyptium (L.) Willd.), Thatch grass (Imperata cylindrica Beauv.), Gold beard grass (Chrysopogon aciculatus (Retz.) Trin.), Torpedo grass (Panicum repens Linn.), and West Indian marsh grass (Hymenachne amplexicaulis (Rudge) Nees.). Fourteen fungal isolates were evaluated for their ability to promote plant growth. Indole 3-acetic acid (IAA) synthesis was observed in all isolates, ranging from 12.70±0.04 to 64.20±0.17 µg/mL. Epichloë sp. KN03R was the isolate that made the most IAA (64.20±0.17 µg/mL), ammonia (0.24±0.02 mg/L), and a phosphate solubilization (halo zone ratio of 1.50±0.87 cm). The growth-promoting efficacy of Epichloë sp. KN03R was tested on Paphiopedilum callosum (Rchb.f.) Stein plantlets under sterile conditions for 8 weeks. The results indicated an increase in fresh weight (104.75±0.35 g/plant), plant height (3.47±0.06 cm), number of shoots (1.88±0.11 shoots/plant), number of leaves (7.98±0.34 leaves/plant), number of roots (4.32±0.40 roots/plant), and root length (3.37±0.21 cm). These results suggest that Epichloë grass endophytic fungus has the ability to promote nonhost plant growth in vitro.