"So, naturalists observe, a flea has smaller fleas that on him prey; and these have smaller still to bite ’em; and so proceed ad infinitum."
- Jonathan Swift

December 27, 2010

December 27 - Macrophomina phaseolina

One of the gifts that the Three Wise Men brought was frankincense, which is derived from the resin of the tree Boswellia serrata. While frankincense has been considered as a remedy for many different types of infectious diseases, B. serrata itself is by no means free from the scourge of infection itself and is plagued by the fungus Macrophomina phaseolina, which causes the disease known as Charcoal Root Rot. This fungus infects more than 300 species of plants, and can cause high mortality among tree seedlings. Macrophomina phaseolina survives and overwinters as small, black spores (call microsclerotia), hidden in the soil or debris from previously infected plants. When a growing root of a plant encounters a dormant spore, it germinates and begins growing all over the root and penetrating into the root cortex. From there, the fungus penetrates through the cortex and inner bark and into the taproot. The infected seedling eventually dies from the gradual destruction of its root system. Just prior to the death of the host, the M. phaseolina produces spores that are deposited in the inner bark of the lower stem and roots. When the host eventually dies and decays, the spores are released into the soil where they wait for an encounter with yet another growing seedling.

Contributed by Tommy Leung.

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