Fungal Biotechnology in Agricultural, Food, and Environmental Applications (Mycology)
Fungi have been utilized for thousands of years and their importance in agriculture, medicine, food production and the environmental sciences is well known. New advances in genomic and metabolomic technologies have allowed further developments in the use of fungi in industry and medicine, increasing the need for a compilation of new applications, developments and technologies across the mycological field.
Applied Mycology brings together a range of contributions, highlighting the diverse nature of current research. Chapters include discussions of fungal associations in the environment, agriculture and forestry, long established and novel applications of fungi in fermentation, the use of fungi in the pharmaceutical industry, the growing recognition of fungal infections, current interests in the use fungal enzymes in biotechnology and the new and emerging field of myconanotechnology.
Demonstrating the broad coverage and importance of mycological research, this book will be of interest to researchers and students in all biological sciences. Have you read this book, or used it for one of your courses? We would love to hear your feedback. Email our reviews team to submit a review. Prothero Michael J.
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Conservation Land Management. Go to Conservation Land Management. They act as natural mycoinsecticides, as the phrase has been termed, that do not harm or affect the plants at all. Instead, acting as dangerous ingested toxins for the specific species of insects they target.
Improving their lethality toward insects has been a main focus of research. Transgenic crossing of genes between different fungi types has seen remarkable success in accomplishing this, creating a recombinatory genome that evolution likely would have eventually gotten to if there had been any selective pressure to protect agricultural crops.
But, lacking that, we can do the work for nature ourselves. Another tactic has been to add genes from the target insects into the fungi. This results in a sort of targeting system, when properly set up, that has the fungus attacking a specific regulatory system in the insects, whether their ability to digest food, their ability to maintain cellular osmotic pressure, or to just go directly after their neural system.
A final application has been to use genes from organisms that are predators to the insects in question. This often means arthropods like spiders and scorpions. Moving venom producing genes into the fungi results in a tremendous boost to their virulence. Since, even though the amount of venom produced by the fungi is so small that anything larger than even a rather large insect would be unaffected, the very small size of most insects leaves them susceptible.
All of these showcase how beneficial fungi can be used against multiple kinds of pests, from other fungi to insects to even weeds if it came to it. Since many of these species of fungi naturally prey on such pests, they are already well suited to helping farmers protect their livelihoods.
Fungal Biotechnology in Agricultural, Food, and Environmental Applications (Mycology)
Unfortunately, the parasitic fungi in particular often find ways to evade even these attempts to stop them. Agriculture is a continuing and ongoing war against pests. Much of what there is to say on the topic of parasitism works closely with the mutualistic relationships already described. But rather than a beneficial relationship that has the fungus working together with its host plant for nutrients, parasitic fungi invade and take the nutrients they desire. The first step to this is to directly invade the plant root cells and set up shop. Fungi have several means to do so.
The simplest is to just physically invade the cell walls by adhering to the outside of the roots and using a specialized cell called an appressorium. This is designed to apply more and more pressure against its outer cell wall in a pointed direction, causing it to puncture through the plant cell wall in turn. This pressure is so strong, it has been found in some fungal species to even be capable of puncturing strengthened mylar sheets. Another way is to use previously mentioned chemical tactics, such as enzymes that break down opposing cell walls.
This is an easy way for the fungi to just remove any strengthened root wall blocking its passage. Since the polymer cutin is often used to reinforce the outer cuticle of plants, especially on leaves and other such structures, some fungi have been found to secrete cutinases that break down this polymer and give access to the invader.
The importance of wood-decay fungi in forest ecosystems
The same can be done by applying cellulases to dissolve any cellulose within plant cells themselves, rapidly enhancing the degradation of their host plant, as is sometimes the goal of a fungal parasite. Lastly, toxic compounds can be applied to infect and weaken a plant overall, letting the fungus just wait until the cells are shriveled and weakened enough to enter and consume the remaining nutrients.
Fungal toxins are often host-specific, allowing a high pathogenicity, meaning the capability to cause disease, for that specific target species. These are sometimes the most dangerous, because in order to be effective, the fungi must often make these general toxins extremely harmful for all plant organisms.
This sometimes even means extreme harm for other organisms, such as humans, that accidentally ingest them. Some do this slowly in order to keep their host alive and allow them to parasitize their host for years to come. Others actively seek to take nutrients as quickly as possible and kill their host in the process. Fungi that prey on plant species that grow in large amounts in close proximity to each other often take this path, as there are plenty of other hosts to target afterwards. All of this might sound quite scary and for farmers and those that work in agriculture, it is.
A widespread outbreak of some plant pathogenic fungi can result in mass famines and the starvation of thousands. So ways to control for these fungi attacks is important, as has been already emphasized many times. The first step in many things in molecular biology, and biotechnology is no exception, is to run a genetic sequencing. In order to find ways to fight against an organism, it must first be understood genetically and have its composite genes deciphered.
This allows for opposing forces to be identified.
But, to run such a sequence, a pure sample must first be obtained. This process was explained back in the history section, but it also allows for a special trick. When growing samples of a pathogenic fungus on a leaf disc culture, this can also be used to find other species of fungi, bacteria, or other microorganisms, that might prey upon the parasitic fungus. Last year, researchers decided to try this approach with coffee rust Hemileia vastatrix , a fungus that routinely destroys more than half of the coffee market worldwide. Or, at least it did in the past.
What the scientists found in their cultures was a rather diverse community. For fungi alone, there were more than 60 different species growing in the same region. By comparing the species growing on the control culture and the rust infected culture, they were able to find 15 mycoparasitic fungi that prey upon coffee rust.
Such a simple method as comparing cultured leaf discs can be very powerful in finding tools to fight against parasitic fungi. These tools are necessary since, much like bacteria, fungi are rampant in combining genes from other fungal species and beyond. Horizontal gene transfer between fungi and other organisms is fairly common, with any average genome likely having hundreds of such obtained genes. This variety gives the fungi versatility in their actions and makes them harder to combat, at least from the agricultural side of things.
Though this abundance of obtained genes also gives scientists an opening to attack. Finding out which genes are transgenically taken from others means that biotech has the capability to target those genes in particular. Since a number of them apply to fungal abilities to invade plants, animals, and others, they are a prime genome location to try and disrupt with any available technology.
The Evolution of Non-Host Resistance. A remarkable innovation over the past several decades has been the advancement of knowledge on the topic of non-host resistance NHR. Namely, the ability of plants to resist pathogens that are specifically evolved to target a particular species of plant that is not that plant in question. It is not the natural host for the pathogen and thus is resistant against it, hence the name. NHR genes can take many forms. This include pre-invasion genes that stop the parasitic fungi from getting into the plant cells in the first place and post-invasion genes that have the plant immune system target and eradicate the invading fungus.
The model organism Arabidopsis has many of these genes and continues to serve as a model for this as well in scientific testing. All of this raises one direct question.
As you might guess, the answer is an emphatic yes. For the horrors of Asian soybean rust, transferring select Arabidopsis NHR genes into soybeans was found to give significant resistance to these transgenic lines. The other stratagem used by scientists is the process of gene silencing either through shutting down of a gene itself or through RNA interference to stop the end product protein from being made. Funny enough, plants already use this process themselves. In a study in , scientists were able to view how cotton plants reacted to infection by the fungus Verticillium dahliae.
What they found is that the plants, as one ploy, start production of a particular set of microRNA and export them into the fungal hyphae invading the plant. Once inside of the fungus, these microRNA began targeting specific gene sequences in order to silence it.