Mycorrhiza

Plants and fungi work as a team.

They live together in the soil. The plant makes food from sunlight. It shares this food with the fungus.

In return, the fungus helps the plant. The fungus finds water in the dirt. It also finds tiny bits of food for the plant. This helps most plants grow well.

Some plants even use this to grow tall. It is a very old way to live. This teamwork started a long time ago.

Plants and fungi can live together in a special way. This is called a mycorrhiza.

This partnership helps both sides. The plant makes sugar from sunlight. It gives this sugar to the fungus.

In return, the fungus helps the plant. It finds water and minerals in the soil. These minerals include things like nitrogen and phosphorus. This helps the plant grow strong.

This way of living is very old. Fossils show it started 407 million years ago. Back then, plants did not even have roots. The fungi acted like a root system for them. Most plants use this system today. This includes many crops like wheat and beans. One common type is called arbuscular mycorrhiza. It is found in 70% of plant species. A scientist named A.B. Frank named them in 1885. Some fungi only live with plants. They cannot survive on their own without a host.

A mycorrhiza is a special way that plants and fungi live together.

This partnership is called a symbiotic association. It happens when fungal hyphae, which are tiny threads, connect to plant roots. They meet on a very small level inside the cells. This connection is very important for the health of the soil. It helps with plant nutrition and soil chemistry. Most of these partnerships are mutualistic, which means both sides help each other. However, in some cases, the relationship can be parasitic.

This partnership works like a trade between two neighbors. The plant uses sunlight to make organic molecules through photosynthesis. It then gives these sugars or lipids to the fungus. In return, the fungus acts like a helper for the plant. It gathers water and mineral nutrients from the soil. These nutrients include phosphorus, nitrogen, or zinc.

The fungus can live inside the root cells or outside them. One type is called arbuscular mycorrhizal fungi, which live inside the cells. Another type is called ectomycorrhizal fungi, which stay on the outside.

Scientists have studied these connections for a long time. A German botanist named A.B. Frank named them in 1885. Before that, others noticed how plants and fungi were linked. In 1881, Franciszek Kamieński saw that one plant relied on fungi from nearby trees. In 1899, Noël Bernard showed that orchids need a specific fungus to grow seeds.

Later, researchers learned much more about how diverse these fungi are. In 2008, scientists sequenced the genome of a fungus called Laccaria bicolor. This helped them see the genetic side of how they work together.

These connections are incredibly old. Fossils from the Rhynie chert show these links existed 407 million years ago.

Back then, early land plants did not have roots yet. The fungi acted like a primitive root system for them. Arbuscular mycorrhizae are the oldest type and are found in 70% of plant species. This includes many crops like cereals and legumes. Other types, like ectomycorrhizae, appeared much later. For example, ectomycorrhizal fossils appear about 48.7 million years ago in the Eocene.

Today, we see these fungi in many different places. Some fungi, like those in the Glomeromycota group, must have a plant to survive. Others can live on their own in the soil. Ericoid mycorrhizae are found in very poor soils in the north and south.

These fungi help plants survive in places where it is hard to find nutrients. This shows how life finds ways to work together. Even the most common plants in your garden might be using this ancient system. It is a hidden world beneath our feet.

A mycorrhiza is a symbiotic association between a fungus and a green plant.

This relationship occurs when fungal hyphae, which are tiny thread-like structures, interconnect with plant roots. They form a physical interface at the cellular level within the plant's rhizosphere. The rhizosphere is the area of soil surrounding the plant root system. These associations are vital for soil biology and soil chemistry. Most mycorrhizal relationships are mutualistic, meaning both organisms benefit. However, in specific species or circumstances, the relationship may become parasitic.

The mechanism of this partnership functions through a specialized exchange of resources. The plant performs photosynthesis to create organic molecules. It then supplies these molecules to the fungus in the form of lipids or sugars. In return, the fungus acts as a resource gatherer for the plant. It extracts water and essential mineral nutrients from the soil. These include critical elements such as phosphorus, nitrogen, or zinc.

This exchange happens either inside the plant's root cells or outside of them.

There are several distinct types of mycorrhizal associations. Arbuscular mycorrhizal fungi are the most common type. They are present in 70% of plant species, including many legumes and cereals. These fungi colonize the host plant's root tissues intracellularly, meaning they grow inside the cells. Ectomycorrhizal fungi represent a different strategy. They colonize the roots extracellularly, remaining outside the cells. Other specialized types include orchid mycorrhizae and ericoid mycorrhizae. Ericoid mycorrhizae are often found in extremely nutrient-poor soils in both the northern and southern hemispheres.

Research into these fungi has a long and detailed history. The term "mycorrhiza" was formally coined in 1885 by the German botanist A.B. Frank. Earlier scientists had already observed these connections. In 1881, Franciszek Kamieński demonstrated that the plant Monotropa hypopitys depended on fungi from nearby trees. In 1899, Noël Bernard established that certain orchids, such as Neottia nidus-avis, require specific fungi for their seeds to germinate.

In 2008, the genome of the ectomycorrhizal fungus Laccaria bicolor was sequenced. This discovery allowed scientists to study the molecular basis of symbiosis through specialized secreted proteins.

These associations are incredibly ancient and helped plants move onto land. Fossil evidence from the Rhynie chert shows mycorrhiza-like associations existed 407 million years ago.

At that time, early land plants like Aglaophyton major lacked true roots. Scientists believe mycorrhizal fungi served as a primitive root system for these plants. Because early soils were nutrient-sparse, plants needed fungi to absorb phosphate. Arbuscular mycorrhizal fungi are the oldest lineage, appearing as early as 450 to 500 million years ago. In contrast, ectomycorrhizal fossils appear much later, around 48.7 million years ago in the Eocene.

Different fungal groups show different levels of dependency on their hosts. The phylum Glomeromycota contains arbuscular mycorrhizal fungi. These are obligate biotrophs, which means they are entirely dependent on plants for survival. There are between 300 and 1,600 identified species in this group. Many of these fungi are generalists with minimal host specificity. Conversely, some ectomycorrhizal fungi are facultatively symbiotic. This means they can live independently in the soil under certain conditions. There are between 20,000 and 25,000 species of ectomycorrhizal fungi in existence.

Evolutionary patterns show that these partnerships have developed many times. While arbuscular mycorrhizae evolved only once, other forms emerged through convergent evolution. For example, ectomycorrhizal relationships in angiosperms are believed to have developed independently at least 18 times. Ericoid mycorrhizae are thought to be the most recent evolutionary development. They evolved approximately 118 million years ago from free-living ancestors. These fungi help plants survive in environments where decaying matter is resistant to microbial decay.

This complex web of life connects the microscopic world of fungi to the massive systems of the Earth's vegetation.