Editing Genetic transformation (section)

=== Fungi ===
There are some methods to produce transgenic [[Fungus|fungi]] most of them being analogous to those used for plants. However, fungi have to be treated differently due to some of their microscopic and biochemical traits:

* A major issue is the [[Dikaryon|dikaryotic state]] that parts of some fungi are in; dikaryotic cells contain two haploid nuclei, one of each parent fungus. If only one of these gets transformed, which is the rule, the percentage of transformed nuclei decreases after each [[Spore|sporulation]].<ref name=":1">{{Cite journal|last1=Poyedinok|first1=N. L.|last2=Blume|first2=Ya. B.|date=March 2018|title=Advances, Problems, and Prospects of Genetic Transformation of Fungi|journal=Cytology and Genetics|volume=52|issue=2|pages=139–154|doi=10.3103/S009545271802007X|s2cid=4561837|issn=0095-4527}}</ref>
* Fungal cell walls are quite thick hindering DNA uptake so (partial) removal is often required;<ref>{{Cite journal|last1=He|first1=Liya|last2=Feng|first2=Jiao|last3=Lu|first3=Sha|last4=Chen|first4=Zhiwen|last5=Chen|first5=Chunmei|last6=He|first6=Ya|last7=Yi|first7=Xiuwen|last8=Xi|first8=Liyan|date=2017|title=Genetic transformation of fungi|journal=The International Journal of Developmental Biology|volume=61|issue=6–7|pages=375–381|doi=10.1387/ijdb.160026lh|pmid=27528043|issn=0214-6282|doi-access=free}}</ref> complete degradation, which is sometimes necessary,<ref name=":1" /> yields [[protoplast]]s.
* Mycelial fungi consist of filamentous [[hypha]]e, which are, if at all, separated by internal cell walls interrupted by pores big enough to enable nutrients and organelles, sometimes even nuclei, to travel through each hypha. As a result, individual cells usually cannot be separated. This is problematic as neighbouring transformed cells may render untransformed ones immune to selection treatments, e.g. by delivering nutrients or proteins for antibiotic resistance.<ref name=":1" />
* Additionally, growth (and thereby mitosis) of these fungi exclusively occurs at the tip of their hyphae which can also deliver issues.<ref name=":1" />

As stated earlier, an array of methods used for plant transformation do also work in fungi:

* Agrobacterium is not only capable of infecting plants but also fungi, however, unlike plants, fungi do not secrete the phenolic compounds necessary to trigger Agrobacterium so that they have to be added, e.g. in the form of [[acetosyringone]].<ref name=":1" />
* Thanks to development of an expression system for small RNAs in fungi the introduction of a [[CRISPR/Cas9-mediated genome editing|CRISPR/CAS9-system]] in fungal cells became possible.<ref name=":1" /> In 2016 the USDA declared that it will not regulate a white button mushroom strain edited with CRISPR/CAS9 to prevent fruit body browning causing a broad discussion about placing CRISPR/CAS9-edited crops on the market.<ref>{{Cite journal|last=Waltz|first=Emily|date=April 2016|title=Gene-edited CRISPR mushroom escapes US regulation|journal=Nature|volume=532|issue=7599|pages=293|doi=10.1038/nature.2016.19754|pmid=27111611|issn=0028-0836|bibcode=2016Natur.532..293W|doi-access=free}}</ref>
* Physical methods like electroporation, biolistics ("gene gun"), [[sonoporation]] that uses cavitation of gas bubbles produced by ultrasound to penetrate the cell membrane, etc. are also applicable to fungi.<ref>{{Cite journal|last1=Rivera|first1=Ana Leonor|last2=Magaña-Ortíz|first2=Denis|last3=Gómez-Lim|first3=Miguel|last4=Fernández|first4=Francisco|last5=Loske|first5=Achim M.|date=June 2014|title=Physical methods for genetic transformation of fungi and yeast|journal=Physics of Life Reviews|volume=11|issue=2|pages=184–203|doi=10.1016/j.plrev.2014.01.007|pmid=24507729|bibcode=2014PhLRv..11..184R}}</ref>