Glomeromycota

Special fungi live in the dirt. They grow near many plant roots. These fungi help plants stay strong.

The fungi and plants help each other. The plants make food from the sun. The fungi take that food to grow. In return, the fungi give things to the plants.

Tiny spores help new fungi grow. Small animals move these spores in the soil. The fungi grow into the plant roots. They make tiny branches inside the root.

These fungi live all over the world. They live in wet lands too. Most plants use them to stay healthy. It is a busy world under our feet.

Glomeromycota are a large group of fungi. They live in soil all over the world. Many of them live in wetlands too. There are about 230 known species in this group.

Most of these fungi help plants grow. They form a bond called arbuscular mycorrhizas. This is a way that fungi and plants live together. The fungi grow inside plant roots. They make tiny, branched parts called arbuscules. These parts help move nutrients back and forth. The plants give the fungi food. The fungi help the plants stay strong against stress.

New fungi grow from tiny spores. These spores can move through the air. Small animals in the soil also move them. When a spore finds a root, it starts to grow. Plants even send out chemicals to attract the fungi.

One special fungus is called Geosiphon pyriformis. It does not work with plants. Instead, it lives with a tiny blue-green thing called Nostoc. This is a type of cyanobacteria. Scientists use special tools to study these fungi. They study their genes to learn how they are related to other life.

Glomeromycota are a very important group of fungi. They live in soils all over the world. You can also find them in wetlands like salt-marshes. There are about 230 different species in this group. Most of these fungi live in a special partnership with plants. This bond is called an arbuscular mycorrhiza. This name describes how they grow with plant roots. These fungi help more than 80% of all plant species. The fungi help plants handle stress from their environment. In return, the plants give the fungi food called carbohydrates.

This partnership works in a very specific way. First, tiny spores move through the soil or the air. Small animals that burrow in the dirt also move them. When a spore finds a root, it starts to grow. Plants even send out chemical signals to attract the fungi. The fungi grow tiny threads called hyphae toward the root. These threads enter the root cells to form arbuscules. These arbuscules are highly branched structures. They allow nutrients to move back and forth between the two living things.

Scientists have spent a long time studying these fungi. At first, they looked at the shape of spore clusters. They used things like color and size to group them. Later, they used new molecular techniques to study their genes. This helped them see how these fungi are related to other life. They found that these fungi share an ancestor with the Dikarya. Now, scientists know this group has four different orders. One special fungus is named Geosiphon pyriformis. It does not live with plants. Instead, it lives with a tiny blue-green thing called Nostoc.

Learning about these fungi can be a hard job for scientists. These fungi are biotrophic, which means they need a living host. This makes it very difficult to grow them in a lab. Scientists had to use root cultures to solve this problem. They also developed a way to study single nuclei from spores. This helps them look at the genes of the fungi. One important gene is called SSU rRNA. It is used to study how different groups are related.

Understanding Glomeromycota helps us understand how nature works together. It shows how two different living things can help each other. The fungi get energy from the plant's photosynthesis. The plants get better access to nutrients in the soil. This is like a trade between two neighbors. Even in dry places like the Sevilleta Arid Lands, these fungi are present. They are a key part of how life grows on land.

Glomeromycota is a major division within the kingdom Fungi. This group includes approximately 230 described species. Most members of this group are famous for forming arbuscular mycorrhizas, or AMs. An arbuscular mycorrhiza is a symbiotic relationship between fungi and plants. These fungi live in the roots of vascular land plants and the thalli of bryophytes. This partnership is vital for life on Earth. It is estimated that more than 80% of all plant species form these connections. Without these fungi, many plants would struggle to grow in different environments.

The mechanism of colonization is a complex biological process. It begins with spores in the soil. These spores are the key players for establishing new hosts. Spores can be moved by air or by animals that burrow in the soil. Once a spore finds a suitable host, it begins to germinate. This process depends on specific environmental conditions. These include the right temperature and the correct amount of nutrients. Host plants even secrete chemical factors. These chemicals attract and help the growing hyphae reach the root system.

Once the fungi reach the root, a specific sequence of events occurs. The hyphae, which are fungal threads, interact with the root hairs. They may also develop structures called appressoria between the epidermal cells of the root. The hyphae then extend into the cortical cells of the root. They penetrate the cell walls but do not break the inner cellular membrane. Instead, they create an internal invagination, which is a folding inward of the membrane. Inside the cell, the hyphae branch out into a structure called an arbuscule. These highly branched arbuscules allow for a two-way movement of nutrients. The plant provides carbohydrates to the fungi. In return, the fungi help the plant manage environmental stresses.

Glomeromycota can be categorized into different groups based on their biology. Most species are terrestrial and live in soils worldwide. They are also found in wetlands, such as salt-marshes, and with epiphytic plants. While most form AMs, there are exceptions. One species, Geosiphon pyriformis, does not form arbuscular mycorrhizas. Instead, it forms an endocytobiotic association with Nostoc cyanobacteria. This means the fungus lives in a close relationship with these blue-green bacteria. Current science places the Glomeromycota within the phylum Mucoromycota. Because of this, the name Glomeromycotina is used to describe the subphylum.

The history of studying these fungi has changed significantly over time. Early scientists used morphology, or the study of physical shapes, to classify them. They looked at spore clusters, which are called sporocarps. They examined wall shapes, colors, and how the fungi reacted to stains. Initially, the genus Glomus was placed in the unrelated Endogonaceae family due to superficial similarities. As researchers cleared up confusion regarding sporocarps, the Glomeromycota were given their own order. This included families like Glomaceae and Gigasporaceae. Modern molecular techniques have since caused major revisions to these classifications.

Today, scientists use genetic tools to understand these fungi more deeply. They study the small-subunit ribosomal RNA, or SSU rRNA. This gene is highly conserved, meaning it stays very similar across different species. This makes it perfect for phylogenetic studies to see how species are related. One challenge is that Glomeromycota are biotrophic. This means they require a living host to survive. Because of this, they are very hard to grow in a laboratory. Scientists have overcome this by using root cultures. They also use a method to sequence a single nucleus from a spore.

Recent research provides even more detail about their presence in nature. A metatranscriptomic survey was conducted in the Sevilleta Arid Lands. This study looked at fungal RNA in the soil. It found that 5.4% of the fungal rRNA reads belonged to Glomeromycota. This was different from older studies that used PCR, or polymerase chain reaction. Those older studies might have underestimated how many of these fungi are actually in the soil. This shows that Glomeromycota are a consistent and important part of many ecosystems. Their ability to connect with the majority of land plants makes them essential to the global food web.