GIANT FUNGUS DIANJUNUS REX DISCOVERED IN CHINA

Why In News?

Mycologists from the Kunming Institute of Botany at the Chinese Academy of Sciences discovered a giant fungus species—named Dianjunus rex—in the forests of Yunnan province, China.

What Is Dianjunus rex?

It is a recently discovered giant fungus species that produces the largest known fruiting bodies in the Ascomycota phylum. It can grow up to 50 cm tall and weigh up to 2.2 kg.

• Scientific Classification: It represents an entirely new species, genus, and family named Dianjunaceae within the order Xylariales.  

• Evolutionary Significance: A "molecular clock" DNA analysis reveals that its lineage dates back 65 million years. It emerged roughly 1 million years after the Cretaceous-Paleogene (K-Pg) mass extinction event that wiped out the dinosaurs.  

• Ecological Role: It is a wood-decomposing fungus. Scientists hypothesize that the massive environmental destruction and sudden abundance of dead plant material after the dinosaur extinction created unique ecological opportunities for this lineage to flourish.  

• Etymology: The name Dianjunus references the ancient Dian Kingdom of Yunnan and the Chinese word for fungus (jun). Rex means king in Latin, denoting its massive size.  

What Is A Fungus?

A fungus (plural: fungi) is a member of a distinct biological kingdom of eukaryotic, heterotrophic organisms that include yeasts, molds, and mushrooms.  

Core Characteristics 

• Cell Structure: Eukaryotic cells containing a true nucleus and membrane-bound organelles.  

• Cell Wall Composition: Unlike plants (which use cellulose) or bacteria (peptidoglycan), fungal cell walls are made of chitin. 

• Nutritional Mode (Absorptive Heterotrophy): They lack chlorophyll and cannot perform photosynthesis. Instead, they secrete digestive enzymes externally to break down complex organic matter and absorb the simpler nutrients. 

• Body Form: Most are multicellular and filamentous (composed of thread-like structures called hyphae that form a network called mycelium), while some are unicellular (such as yeast).  

• Reproduction: Reproduce via vegetative methods (budding, fission, fragmentation), asexual spores, and sexual reproduction.  

• Study: The scientific discipline dedicated to studying fungi is called Mycology.  

Ecological and Economic Significance

• Decomposers & Recyclers: They break down dead plant and animal matter, playing a primary role in nutrient cycling and soil fertility.  

• Symbiotic Relationships:

• Mycorrhizae: Association between fungi and plant roots (helps plants absorb water and minerals like phosphorus).

• Lichens: Symbiotic association between algae (or cyanobacteria) and fungi. 

• Industrial & Medical Uses:

• Antibiotics (e.g., Penicillin from the mold Penicillium).

• Food production (e.g., Saccharomyces cerevisiae or baker's yeast for baking and brewing, mushrooms, truffles, and Gucchi in India).  

• Pathogens & Toxins:

• Causes plant and animal diseases (e.g., Mucormycosis or "Black Fungus" caused by Mucor and Rhizopus, ringworm/tinea by dermatophytes, and rusts/smuts in crops).

• Produces lethal mycotoxins like Aflatoxins (from Aspergillus species) which are potent natural carcinogens found in poorly stored grains and groundnuts.  

Source: THEHINDU