Fungal Communities in the Native New Zealand Medicinal Plant Pseudowintera colorata (Horopito) Are Determined by Plant Organ Type and Host Maturity with Key Members Promoting Plant Growth

Neeraj Purushotham; Eirian Jones; Jana Monk; Hayley Ridgway

doi:10.3390/microorganisms9122576

Fungal Communities in the Native New Zealand Medicinal Plant Pseudowintera colorata (Horopito) Are Determined by Plant Organ Type and Host Maturity with Key Members Promoting Plant Growth

Microorganisms. 2021 Dec 13;9(12):2576. doi: 10.3390/microorganisms9122576.

Authors

Neeraj Purushotham¹, Eirian Jones¹, Jana Monk², Hayley Ridgway^{1

3}

Affiliations

¹ Department of Pest-Management and Conservation, Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln 7647, New Zealand.
² AsureQuality, Lincoln 7647, New Zealand.
³ The New Zealand Institute for Plant and Food Research Limited, Christchurch 7608, New Zealand.

Abstract

The plant Pseudowintera colorata is well known for its antimicrobial and medicinal properties and is endemic to New Zealand. Using PCR-Denaturing gradient gel electrophoresis (DGGE), we investigated the factors influencing the composition of endophytic fungal communities in P. colorata from ten distinct sites across New Zealand. Our results showed that plant organs of P. colorata influenced the diversity and richness of endophytic fungi (PERMANOVA, p < 0.05). In addition, plant maturity and its interactions revealed that endophytic fungal communities formed discrete clusters in leaves, stems, and roots of mature and immature P. colorata plants (PERMANOVA; p = 0.002, p = 0.001 and p = 0.039, respectively). For identifying isolates with biocontrol potential, dual culture tests were set up against four different phytopathogenic fungi. Isolates with high activity (zone of inhibition > 10 mm) were sequenced and identified as Trichoderma harzianum, Pezicula neosporulosa, Fusariumtricinctum, Metarhizium sp., and Chaetomium sp. Applying selected endophytic fungi (n = 7) as soil drenchers significantly increased the growth of P. colorata seedlings and produced more internodes. Seedling shoots treated with Trichoderma sp. PRY2BA21 were 2.2 × longer (8.36 cm) than the untreated controls (3.72 cm). Our results elucidate the main plant factors influencing fungal community composition and demonstrate a role for endophytic fungi in P. colorata growth and further demonstrate that medicinal plants are a rich source of endophytes with potential as biocontrol agents.

Keywords: DGGE; New Zealand; antifungal activity; biocontrol; endophytes; endophytic fungi; medicinal plant; microbial ecology; plant pathogens; plant-microbe interactions.