User:Csolene/Draft-solene-clemence-hericium-erinaceus

Morphology
Hericium erinaceus ' fruitbodies are large, irregular bulbous tubercules of 5-40 cm in diameter. Fruitbodies are dominated by crowded, hanging, spore-producing spines, which are 10-40 mm long. Fruitbodies and spines are white to cream colored, but can turn yellowisch brown when they get older.

The hyphal system is monomitic, amyloid, and comprises thin to thick-walled hyphae that are about 3 – 15 μm wide. The hyphae also contain clamped septa and gloeoplerous elements (filled with oily, resinuous substances)..

The basidium is about 25-40 μm long and 5-7 μm wide, contains four spores and possesses a basal clamp. The white amyloid basidiospores measure around 5-7 μm in length and 4-5 μm in width. Spore shape is described as subglobose to short ellipsoid. Spore surface is smooth to finely roughened.

Development
Optimum temperature for radial extension of the mycelium is at 25 °C (3.3-6.7 mm d -1) with slow growth at 5 °C and 10 °C and no growth at 35 °C. The optimum pH is 5.5-6, pH above 8 or under 2 were too extreme for mycelial growth. H. erinaceus is unable to grow with a water potential lower than -5 Mpa.

Hericium erinaceus fruitbodies are mainly produced annually from August to November in Europe. It was observed that H. erinaceus could fruit intermittently for 20 years on the same dead tree, and 40 years of survival is hypothetised. H. erinaceus ' mating system of US species was shown to be tetrapolar (bifactorial), which means there is 25% chance of successful mating with mycelium formed from spores taken from a single fruit body. This might favour outbreeding.

Monokaryotic mycelium growth of H. erinaceus is slower than dikaryotic growth and only about a low percentage of monokaryotic cultures yield fruitbodies. Monokaryotic fruitbodies are also smaller than dikaryotic fruitbodies.

Spore production is highest at midday, relatively to daily temperature increase and relative humidity decrease. Daily changes towards lower relative humidity can favor sporulation, but low level of relative humidity would on the contrary not favor high total spore production. Growth regulators, e.g., 2,4-Dichlorophenoxyacetic acid and gibberellin, were observed to have an advantageous impact on spore germination. Other technologies like red and green laser light of low intensity stimulated spore germination as well as the vegetative growth of mycelium. Argon and helium lasers also contributed to the acceleration of fructification so that the weights of fruitbodies were increased and the yield of fruitbodies were also increased by 36–51%.

Interactions with other species
Brennandania lambi (Acari: Pygmephoroidea) is a mite pest of fungi culture in China. This mite was able to develop and reproduce on the mycelium of H. erinaceus. Farm hygiene and heating treatments are the most important pest management strategies that should be done to counter this acari. Further studies should be done on natural enemies of this mite and selective acaricides to biologically and chemically control B. lambi.

The use of H. erinaceus to control tomato diseases seems promising. Fungus extract inhibited the mycelial growth of tomato pathogenic fungi including Phytophthora capsici and the growth of the bacteria Ralstonia solanacearum.

Hericium species are good competitors against other wood colonisers. They show ability to maintain their place on dead wood, also against secondary colonisers like e.g. Trametes versicolor and Stereum hirsutum. H. erinaceus was showed being slightly more combative than other fungi tooth species like Creolophus cirrhatus and Hericium coralloides.

Genetic & breeding
A great lack of genetic and molecular knowldeges prevent the development of elite cultivars of H. erinaceus. Breeding targets in mushrooms are quantitaty of bioactive compounds, higher yields, better quality and higher pest and disease resistance. But a lot of traits of interest might by governed by QTLs (quantitative traits loci), so that QTLs identification should be done in order to faciliate marker assissted selection and breeding progress.