Bacteria in the medicinal plant horopito

Endophytic bacteria play crucial roles in plant development by enhancing plant metabolism, improving nutrient uptake, influencing overall fitness, and mediating biological control of phytopathogens. Microbial communities differ between plant species and characterising them could advance understanding of their key roles in plant health and ecology. However, there is limited information on the composition of endophytic bacteria found in the tissues of native medicinal plants. Pseudowintera colorata (horopito) is a primitive angiosperm and native New Zealand medicinal plant recognised for its antimicrobial properties.

For the first time, scientists from Lincoln University, AsureQuality, and Plant & Food Research have described the bacterial endomicrobiome of P. colorata. 

In this paper, the diversity and abundance of bacterial endophytes in P. colorata were influenced by tissue type. However, several species found commonly throughout the plant were determined to be part of the “core endomicrobiome”. Some of the bacteria were able to inhibit the growth of selected phytopathogenic fungi in culture, indicating they may have potential as biocontrol agents.

All the tissues sampled (roots, stems and leaves) contained at least one culturable endophyte. These results support the theory that every plant on earth is colonised by microorganisms.

Characterisation of a core endomicrobiome of P. colorata has identified the key bacteria that are likely to be important for the plant’s physiological processes. Pseudowintera colorata contains several culturable endophytic bacteria with antimicrobial properties, some of which were able to improve plant growth. Future study into the roles of selected members of the endomicrobiome could further identify their functional importance in this plant.

Journal Reference:Purushotham N, Jones E, Monk J, Ridgway H 2020. Community Structure, Diversity and Potential of Endophytic Bacteria in the Primitive New Zealand Medicinal Plant Pseudowintera colarata. Plants https://doi.org/10.3390/plants9020156