The mysterious and filthy underground life cycle of the Black Diamond.
It is May and the world outside is waking up. My senses are bombarded with droning sounds of busy bees in my ears; fragrant scents of pollen in my nose and the sight of birds, twigs in mouths, building their nests, filling my imagination with the promise of new life and a rewarding summer. But what my senses do not tell me is that the underground world of tuber melanosporum is also frothing with activity.
We all know the Perigord truffle by the knobbly black object that we excitedly shave over a mouthwatering supper, so that is where we shall start. The truffle itself is rather like the fruit of the fungus. Let's take the example of the cherry. The tree labours throughout the year to create these delicious morsels. They are eaten, carried in the digestive system of, say, a magpie and excreted out in a nice newly fertilised area, where the new tree shall grow. Clever little cherry.
Following this example: the truffle is the cherry, the spores are the seeds, and the magpie is a pig. But the truffle has a much more difficult chance of being spotted, for this delicious little morsel lies beneath the soil. No shiny red coat for her. Inedible or even offputting in appearance, how does she attract attention? The answer is literally in front of us - up our noses and in our mouths! There is nothing quite like the taste and aroma of a fresh truffle, and how clever she is that we, just like our pig friends, return to the same tree roots year upon year to unashamedly gobble away. It has taken hundreds of thousands of years of selective breeding for the truffle to perfect her scent and taste. Those that do not make the cut remain in the ground, rotting quietly away. Consequently, the Perigord truffle has honed her appeal so that we can profit from mother nature's efforts with each sniff of truffle laden soil, and more to the point, with each bite of, for example, the decadent Black Diamond scrambled duck eggs with Tastou fried truffle sandwiches. Infact, the truffle smells so good that truffières such as ours have to defend our underground prize from the local sanglier population who can decimate entire fields with a single midnight feast.
Once they have delighted the taste buds, the truffle will travel with the lucky pig until they eventually depart from the digestive system; releasing truffle seeds (spores) into an area up to several kilometres away. Here, the spores will germinate and form strings (called hyphae). Imagine, if you will, the hundreds of sea turtles hatching on the sunny beach and scampering to the safety of the sea. The fine strings of the fungi, like the turtles, are in search of a safe home; this time, in the form of specific plant roots. Desperate, they reach out quickly to a host to ensure their survival (assuming of course that there isn't another ectomycorrhizal fungus already resident). While the sea for the baby turtles (so far as we know) remains totally nonchalant with resolute imperviousness to the cuteness of baby turtles; the plants conversely are somehow 'aware' of the growth of the mycelium and have the 'understanding' that what this particular little string lacks in cuteness, it makes up for in usefulness. By the magic of nature, the plant knows, through memory of ancient relationships, that these baby truffles will help them in a mutually beneficial friendship for years to come. Both the plant and the truffle hyphae release chemicals that will attract one another in their dark underground world. "Receptive plant roots produce plumes of volatile compounds that drift through the soils and cause spores to sprout and hyphae to branch and grow faster." (Entangled life, Merlin Sheldrake). In answer to their call, the truffle hyphae also release hormones that encourage plant roots to grow more branched, increasing the likelihood of meeting. And once they finally meet, these strings have a place to call home.
It's now time to colonise. The delicate threads of the growing truffle fungi will thrive under the right conditions such as the climate and soil structure. Black gloves (mycorhizes) form around the roots of the host plant. Helpfully infecting the plant, the fungus will receive nutrients such as carbohydrates in exchange for finding the plant other nutrients such as phosphorous using its long, penetrative hyphae. The tree is more than happy to provide shelter to the fungus so that it can then be fed nutrients it would otherwise struggle to attain and water during periods of drought. A truly symbiotic relationship.
Every part of the truffle is surrounded in complexity - the smell, the taste, the growth. The reproduction is no different. At around about this time of year (May), the underground networks begin to develop their sexuality (let's use the terms male and female as these are most familiar). Like many other organisms of the plant and animal kingdoms, this fungi is, unbeknown to us, slipping into naughty night attire and preparing for a rampant month! This subterranean fungus takes two to tango - it reproduces sexually; there are two parents, each contributing to half of the DNA of the new 'baby'. Scientists believe that 'male' and 'female' hyphae will attract one another by releasing pheromones. On meeting, they evaluate their compatibility and fuse, or not. Strangely, as long as there are two individuals of the opposite 'sex', either one may become the 'mother' or 'father'. The 'father' provides his genetic offering, while the 'mother' grows the truffle.
After 'doing it in the dark' (apologies), the 'fruit' will begin to form. In June, the truffettes (yes, that is what baby truffles are called!) appear. Small at first, the truffettes then undergo rapid growth through August and September. After this time they reach maturity when their delightful taste and aroma are at their peak. And then they lie in wait, below the soil, in their secret, fascinating world until they are unearthed in the winter.
The incredible taste and smell of the truffle is almost impossible to describe. They have such depth and refinement and as such have been enjoyed by humans for hundreds of years for their gastronomic value and also for aphrodisiac sensations and alluring mystery. It has been universally agreed that there is something special that happens when you eat one of these tasty treats. Humans enjoy the truffle so much that we actually dedicate large areas to the colonisation of this incredible fungus. It's amazing how fungi have a way of encouraging this sort of behaviour. There are even ants (leafcutter ants), who cut leaves. But they do not eat the leaves. Instead they carry the leaves deep underground into their ant cathedral and, combining the leaf with their saliva, grow, tend and harvest the fungi that appears. Just as a farmer tends carefully to his truffière. How could an ant, with a brain the size of a pinhead, know to do this? Quite simply, the ant depends on it for survival. Has he been manipulated by the fungus? It begs the question - who is in charge, the truffle or us?
Clever little truffle.