(Photograph = Fungal Cultures, David Midgley)
Introduction
Fungi associate with nearly all plants. They colonize roots and live on the surfaces of stems and leaves, and they can even grow inside plants. Fungi that live inside plants are called endophytes (endo = inside). Because host plants often grow normally, these fungi generally cause little harm and may even help the plant.
The Details
Scientists examined 21 cactus species in Arizona for endophytes. The study included multiple species of Opuntia, Cylindropuntia, Echinocereus, and Mammillaria, and also a Consolea species and Carnegiea gigantea.
Up to seven fungal species were found inside Cylindropuntia fulgida—high for cacti but low compared to many tropical plants. In rainy tropical regions, a single plant may host 20 or more endophyte species.
The fungi included:
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Phoma
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Aureobasidium
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Alternaria
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Fusarium
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Ascochyta
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Chaetomium
The researchers did not find Colletotrichum, Phomopsis, or Phyllosticta, which are often reported from tropical plants. Overall, while many fungi were present in these desert cacti, diversity was relatively low compared to tropical hosts.
Additional Reading: Endophytic Fungi Associated with Cacti in Arizona
