Chinese scientists have found potential reasons why red mushrooms are difficult to cultivate

Wild red mushroom fruiting body. Wu Qingping team Courtesy photo

Recently, the team of Wu Qingping, academician of the Chinese Academy of Engineering and honorary director of the Institute of Microbiology of the Guangdong Academy of Sciences, found a potential key factor restricting the artificial cultivation of red mushrooms. The related research was published in Gene under the title of "Whole Genome Sequencing of Red Mushroom and Its Association with Mycorrhizal Characteristics".

Red mushroom is a wild edible mushroom variety with distinct regional characteristics, of which the gray meat red mushroom is a famous exophytic mycorrhizal edible mushroom, mainly distributed in southern China. Because it is rich in a variety of vitamins, amino acids and minerals that are beneficial to the human body, it is known as a longevity food by the locals. Due to the difficulty of growing mycelium of red mushrooms on artificial culture media, there is no accurate method for artificial cultivation of fruiting bodies. Edible red mushrooms in the south are commonly known as "great red mushrooms", containing 3 phylogenous branches that are monophyletic to each other, and the gray meat red mushroom is only one of the branches, and the species similarity is very high, so the gray meat red mushroom is often confused with other red mushrooms.

Through the investigation and identification of red mushroom resources in South China, the researchers obtained accurate fruiting bodies of gray meat red mushrooms, extracted high-quality genomic DNA and used second- and third-generation sequencing techniques to sequence the genomes of gray mushrooms, and then assembled the high-throughput sequencing data from scratch, and used GeneMark-ES, BLAST, CAZy and other databases for functional gene annotation. A phylogenetic tree was constructed based on single-copy genes of different vegetative fungi, and four representative species were compared with the gray mushroom.

Through the research analysis, it was found that the distribution of carbohydrate hydrolase in the gray mushroom is similar to that of other mycorrhizal fungi such as matsutake mushroom and boletus, while the number and type are less than that of saprophytic bacteria, especially carbohydrate binding modules (CBMs) and carbohydrate esterase (Ces), which may be a potential reason for its difficulty in using artificial carbon source medium to complete growth. No small secretory proteins (MiSSPs) associated with mycorrhizal induction were found in the mushroom, suggesting that there may be some special effector proteins that interact with the host plant in the mushroom.

"The conventional method of studying the determination of high-quality genomes by macromyps is to use their mononuclear hyphae, and red mushrooms are a symbiotic bacteria that have not been isolated to date, and it is very difficult to determine their genomes with fresh fruiting bodies." Hu Huiping, a senior engineer at the Institute of Microbiology of the Guangdong Academy of Sciences, told China Science Daily.

The results of this study provide genetic data support for the study of the evolution of vegetative ecology of macrofunges, especially mycorrhizal fungi, and lay the foundation for the next step of screening the nutrient sources available for gray mushrooms.

Related thesis information: https://doi.org/10.1016/j.gene.2021.145996