Q&A with Philip G. Miles

Philip G. Miles, is an expert in the biology of plants and fungi, and serves as president of the World Society of Mushroom Biology and Mushroom Products. A faculty member since 1956, he is a 1998 recipient of the Chancellor's Award for Excellence in Teaching.

What got you interested in studying edible fungi, especially mushrooms?

When I was a graduate student, there was great interest in fungi as experimental organisms, especially in the area of biochemical genetics. My first studies involved research on the genetic control and physiology of sexual mechanisms in basidiomycetes, a class of fungi including mushrooms in which the genetic control of sexuality is relatively complex. For years, my students and I carried on investigations involving a common wood-rotting basidiomycete called Schizophyllum commune, which is an excellent experimental organism. Although Schizophyllum is not an edible mushroom, about 20 years ago I began to apply some of the things that we had learned about the genetics and development of Schizophyllum to some of the edible basidiomycetes. Many of these mushrooms had proved to be recalcitrant in fruiting in culture or in mushroom houses, and their genetics had not been firmly established. At this time, I also became a colleague of Prof. S.T. Chang of the Chinese University of Hong Kong, with whom I have collaborated for many years and who is a world authority in this field, as well as working with other scientists in Asia in studies of edible mushrooms.

Do you eat many mushrooms yourself?

Yes. I enjoy many mushrooms, especially the fresh shiitake, wood's ear, portabella, and others that now are readily available in our local markets.

What is the benefit to adding mushrooms to one's diet?

Mushrooms are relatively high in protein of good quality, containing all the essential amino acids and being rich in lysine and leucine, which are either low or lacking in most staple cereal foods. Mushrooms are low in total fat and have a high percentage of polyunsaturated fatty acids. They have relatively large amounts of carbohydrates, and most species possess nutritionally valuable amounts of fiber. Mushrooms contain significant amounts of water-soluble vitamins (thiamine, riboflavin, niacin and ascorbic acid), as well as minerals. There also is evidence that some species produce compounds that enhance the patient's host defense mechanism, which may offset some of the detrimental side effects brought about by anti-cancer chemotherapy.

How can you tell a dangerous mushroom from a good one in the forest or in your backyard?

Every course or textbook on mycology (the science that deals with fungi) carries a statement such as this. There are no simple tests to tell a poisonous from a non-poisonous mushroom. An accurate identification as to species is essential and then one must know the history of that species as the edibility. You may only make one mistake! If it hasn't been grown on a mushroom farm and sold in the market, it should be avoided except by those capable of making 100 percent accurate identifications. You may miss some very tasty mushrooms in this way, but at least you'll live to enjoy other things.

What is your favorite mushroom-edible or nonedible-and why?

I'll hedge on the answer to this in the following way: 1. My favorite edible mushroom is the pine mushroom (Tricholoma matsutake) for reason of its fabulous flavor, which enhances many dishes. It is often used in sukiyaki in Japan. It is very expensive and not readily available in the United States. I have two favorite non-edible mushrooms-Schizophyllum commune for its value as an experimental organism, and Ganoderma lucidum for the products it produces that are being demonstrated to have important medicinal values.

How has the growing interest in gourmet mushrooms, such as shiitake and porcini, affected your research?

The growing interest in gourmet or exotic mushrooms is the direct result of research (not mine). In Asia and in Europe, many species of mushrooms have been eaten and enjoyed for a long period of time, while we Americans had only the button mushroom or champignon (Agaricus bisporus) available in the market. Now that mushroom scientists have learned how to produce mushrooms such as shiitake, the oyster mushroom (Pleurotus ostreatus) and others commercially in mushroom houses, we have a greater choice. This greater interest has encouraged many to study mushroom biology.

How could mushroom development solve global hunger problems?

It can't solve the problem, but it can contribute to the solution. As previously mentioned, mushrooms are a good source of protein, which is deficient in the diet of a high percentage of the world's population. Furthermore, they can be grown on waste materials from agriculture, forestry, industry and households, so the substrates are inexpensive. In addition, not much land or space is required for mushroom farms. Workshops have been presented worldwide on mushroom cultivation in developing countries. Today many developing countries are producing mushrooms in large amounts. One of the most gratifying experiences in my professional career was to visit a number of places in China to lecture and participate in workshops on mushroom cultivation.

Are mushrooms hard to grow?

Growing mushrooms is an art, as well as a science, much in the same way that wine making is. However, the basic principles are well known and easy to understand. If one wants to start a small mushroom farm, it is best to gain some practical experience by spending time with a successful grower. There are also short courses given at places such as Penn State on mushroom cultivation.

What makes some mushrooms hallucinogenic?

A few genera of fungi are known to produce hallucinogenic compounds. The best known of these genera is Psilocybe, and 81 species of Psilocybe have been reported to be hallucinogenic. There are several compounds of which psilocybin is best known, and these compounds have hallucinogenic properties similar to those of d-lysergic acid diethylamide (LSD). When one hears the way that they act on the central nervous system, it is clear that no sensible person would consider recreational use of psilocybin. Their consumption can be dangerous, although the drug is less potent than LSD.

What's something that people don't know about mushrooms but should?

Their role as nature's trashburners. Here I am speaking of fungi in general. Fungi and bacteria are essential in decomposing organic matter in nature and thus play an essential role in the cycling of carbon.

What question do you wish I had asked, and how would you have answered it?

What is a mushroom? Traditionally, the mushroom has been defined as a fleshy, aerial umbrella-shaped, fruiting body of the class Basidiomycetes. Common usage had included some members of the class Ascomycetes, such as the truffle, as mushrooms. These and others should be included in the definition of mushroom, so we defined a mushroom in the following way. A mushroom is a macrofungus with a distinctive fruiting body that is large enough to be seen by the naked eye and to be picked up by hand. It can be either above or below ground, include both fleshy and non-fleshy textured macrofungi and also includes edible, non-edible, poisonous and medicinal species. The discipline that is concerned with the scientific study of mushrooms is Mushroom Biology. The World Society of Mushroom Biology and Mushroom Products has had two international conferences, the first in Hong Kong in 1993, the second at Penn State in 1996, and the third will be held in Sydney, Australia, in October, 1999.