Value System

An unavoidable fact that affects all life on this planet—including humans and fungi—is that we age. When we are young, the number of downstream cell divisions is vast, but incrementally declines as we grow older. Recently, cell division limiting factors have been attributable to a shortening of telomeres.

Telomeres are the protective region at the end of the chromosome, and the role that the enzyme telomerase plays is in the repairing and replication of chromosomal DNA. These models serve to explain what we all know: as we age, we become less vital and more susceptible to disease. The same is true with mushroom strains.

T – Value System

Our value system involves monitoring the age of cultures by tracking the frequency of transfers made to the original culture.

To illustrate, when we collect a species from the wild and initiate the first spore germination or tissue-culture/clone, we designate its age as T-0. The term “T” stands for Transfer, and documents the number of transfers made to the original culture. Subsequent transfers of the original culture from one matrix to the next are then labeled in increments of T-1, T-2, and so forth.

Each time we transfer or extract a small piece of mycelium, we’re essentially taking only a portion of the cells present in the original culture. This process of transferring or extracting mycelium results in the division of the overall cell population. As cells divide during this process, the telomeres at the ends of their chromosomes begin to shorten.

The primary objective of this value system is to preserve strains either close to their wild origins or at their optimal fruiting potential. This systematic monitoring is crucial for maintaining strains at their peak vitality, ultimately ensuring that we provide our customers with fungal strains that exhibit the highest efficacy.

Sourcing Our Strains

We create our diverse mushroom cultures through our wild foraging expeditions by cloning mushrooms and diligently sourcing spores. We also collaboration with fellow forages/breeders who share our values. We gather cultures and wild spores from these like-minded forages/breeders to contribute to the diversity of our cultures.

Cloning

In our approach to working with wild mushrooms, one technique includes cloning, this is done by extracting a small tissue sample from the interior of a mature mushroom. Throughout this procedure, we replicate only the observable characteristics, referred to as the (phenotype), rather than the full genetic composition (genotype). These observable traits encompass features such as the mushroom’s shape, color, and size. Cloning maintains these traits by reproducing the specific cells responsible for expressing these characteristics.

Working With Spores

When establishing cultures from spores, we adopt a systematic procedure by isolating haploid single spore isolates (SSI). This involves employing a serial dilution method to dilute the spores and isolate individual spores on petri dishes. Additionally, when utilizing the serial dilution method, a microscope is employed to estimate the spore count of both the stock solution and subsequent serial dilutions. After adequately diluting our spores, we apply the serial dilution to petri dishes for spore germination.

Clamp Connections

Subsequent to germination, our aim is to isolate haploid mycelium (monokaryotic), and to make sure it’s really haploid, we check for specific connections called clamp connections.

Clamp connections play a vital role in ensuring the proper distribution of nuclei, maintaining genetic stability.

Their presence is an important indicator of the successful completion of the mating process. Upon confirming the absence of clamp connections, we can be certain that the culture is indeed haploid.

Preservation & Mating

At this point, we create T-1 master slant backups to ensure the preservation of our haploid cultures. After creating T-1 slant backups, we undertake an extensive mating process.

Mating Type Testing for mushroom breeding — Each SSI is paired with every other SSI in our selection. For instance, if there are 5 SSIs (numbered 1 through 5), SSI (1) is paired with (2), (3), (4), and (5). Simultaneously, SSI (2) is paired with (1), (3), (4), and (5), and so on.

It’s important to note that not all spore combinations will be compatible for mating. This thorough mating approach allows us to test all the compatible mating types.

Mini Trials

Once we identify compatible SSIs we conduct mini-trials on these strains (which involves growing and fruiting each strain). During our mini-trials we will be testing for things such as, phenotype’s, growth rates, adaptability, robust immune systems, etc.,.

Selective Introgression Breeding

Introgression breeding transfers specific genes or traits from one species to another through repeated backcrossing.

Backcrossing is a breeding technique that aims to strengthen or “solidify” specific desired traits within a population. It involves mating an offspring with one of its parents to transfer particular traits from one variety into the preferred genetic background of another. This process helps concentrate and maintain the desired traits in subsequent generations.

Interogression Gene Transfer — Introgression breeding involves the transfer of genes from one species or population to another through repeated backcrossing of a hybrid with one of its parents. The goal is to incorporate specific desirable traits from the parent species into the genetic makeup of the hybrid population.

Abbreviations

Notably, you may see abriviations on you culture such as (T-2, F-1, BC-3).

The term “F-1” or “First Filial Generation” (also known as F-1 Hybrid) is used in to describe the first generation of offspring resulting from the crossbreeding or mating of two distinct individuals or parent organisms.

Similarly, the term “BC-3” (Backcross) is employed to specify the number of backcrosses performed on the culture. For instance, crossing an F1 with one of its parents (or a genetically similar individual) yields a BC-1. Subsequently, conducting another cross of the BC-1 with the same parent (or a genetically similar individual) produces a BC-2.

Conclusion

Mushrooms have immune systems just like people. Over the years, I have received mushroom cultures from fellow mushroom enthusiasts, with no information on their age. Often these cultures would suddenly slow in their growth, become more susceptible to disease or even stop growing altogether.

At Cape Town Exotic Mushrooms, we keep the strains we isolate close to their wild genetic origins by using our T value system. This ensures exceptional vigour and disease resistance.

We are able to keep the T value low by making sufficient backups of the cultures during the original culturing. We then store our pure master cultures under deep refrigeration in our mycological laboratories. Our mushroom strains are genetically only a few weeks old, even though we isolated some of our strains years ago.

With mushroom cultures, small mistakes make for big problems. I find it surprising that many culture libraries are unfamiliar with the importance of maintaining young cultures. Most people in the general public are unaware that a small tissue fragment, the size of your little fingernail, can be expanded into hundreds or even thousands of kilograms of fungal biomass within a short period of time.

Unless the strains have sufficient vitality, they will often fail to produce healthy, vigorous mycelium. These strains often do not contain all the beneficial compounds found in identical strains growing in the wild. What this ultimately means is that the consumer may be getting a product that is far inferior to ones grown from younger strains of mushrooms.