Editing Serotonin (section)

===Edible plants and mushrooms===
In drying [[seed]]s, serotonin production is a way to get rid of the buildup of poisonous [[ammonia]]. The ammonia is collected and placed in the [[indole]] part of <small>L</small>-[[tryptophan]], which is then [[decarboxylation|decarboxylated]] by [[Aromatic L-amino acid decarboxylase|tryptophan decarboxylase]] to give tryptamine, which is then [[hydroxylation|hydroxylated]] by a [[cytochrome P450 monooxygenase]], yielding serotonin.<ref name="Schröder et al.">{{cite book | vauthors = Schröder P, Abele C, Gohr P, Stuhlfauth-Roisch U, Grosse W | chapter = Latest on Enzymology of Serotonin Biosynthesis in Walnut Seeds | volume = 467 | pages = 637–644 | year = 1999 | pmid = 10721112 | doi = 10.1007/978-1-4615-4709-9_81 | isbn = 978-0-306-46204-7 | series = Advances in Experimental Medicine and Biology | title = Tryptophan, Serotonin, and Melatonin }}</ref>

However, since serotonin is a major gastrointestinal tract modulator, it may be produced in the fruits of plants as a way of speeding the passage of seeds through the digestive tract, in the same way as many well-known seed and fruit associated laxatives. Serotonin is found in [[Edible mushroom|mushrooms]], [[fruit]]s, and [[vegetable]]s. The highest values of 25–400&nbsp;mg/kg have been found in nuts of the [[walnut]] (''Juglans'') and [[hickory]] (''Carya'') genera. Serotonin concentrations of 3–30&nbsp;mg/kg have been found in [[Plantain (cooking)|plantains]], [[pineapple]]s, [[banana]], [[kiwifruit]], [[plum]]s, and [[tomato]]es. Moderate levels from 0.1–3&nbsp;mg/kg have been found in a wide range of tested vegetables.<ref name=feld>{{cite journal | vauthors = Feldman JM, Lee EM | title = Serotonin content of foods: effect on urinary excretion of 5-hydroxyindoleacetic acid | journal = The American Journal of Clinical Nutrition | volume = 42 | issue = 4 | pages = 639–643 | date = October 1985 | pmid = 2413754 | doi = 10.1093/ajcn/42.4.639 | doi-access = free }}</ref><ref name="Ramakrishna_2011" />

Serotonin is one compound of the poison contained in [[stinging nettle]]s (''Urtica dioica''), where it causes pain on injection in the same manner as its presence in insect venoms.<ref name="Erspamer-1966" /> It is also naturally found in ''[[Paramuricea clavata]]'', or the Red Sea Fan.<ref>{{cite journal | vauthors = Pénez N, Culioli G, Pérez T, Briand JF, Thomas OP, Blache Y | title = Antifouling properties of simple indole and purine alkaloids from the Mediterranean gorgonian Paramuricea clavata | journal = Journal of Natural Products | volume = 74 | issue = 10 | pages = 2304–2308 | date = October 2011 | pmid = 21939218 | doi = 10.1021/np200537v | bibcode = 2011JNAtP..74.2304P }}</ref>

Serotonin and tryptophan have been found in chocolate with varying cocoa contents. The highest serotonin content (2.93&nbsp;μg/g) was found in chocolate with 85% cocoa, and the highest tryptophan content (13.27–13.34&nbsp;μg/g) was found in 70–85% cocoa. The intermediate in the synthesis from tryptophan to serotonin, 5-hydroxytryptophan, was not found.<ref>{{cite journal | vauthors = Guillén-Casla V, Rosales-Conrado N, León-González ME, Pérez-Arribas LV, Polo-Díez LM | title = Determination of serotonin and its precursors in chocolate samples by capillary liquid chromatography with mass spectrometry detection | journal = Journal of Chromatography A | volume = 1232 | pages = 158–165 | date = April 2012 | pmid = 22186492 | doi = 10.1016/j.chroma.2011.11.037 }}</ref>

Root development in ''[[Arabidopsis thaliana]]'' is stimulated and modulated by serotonin – in various ways at various concentrations.<ref name="Pelagio-Flores-et-al-2011">{{cite journal | vauthors = Pelagio-Flores R, Ortíz-Castro R, Méndez-Bravo A, Macías-Rodríguez L, López-Bucio J | title = Serotonin, a tryptophan-derived signal conserved in plants and animals, regulates root system architecture probably acting as a natural auxin inhibitor in Arabidopsis thaliana | journal = Plant & Cell Physiology | volume = 52 | issue = 3 | pages = 490–508 | date = March 2011 | pmid = 21252298 | doi = 10.1093/pcp/pcr006 | publisher = [[Oxford University Press]] (OUP) | doi-access = free }}</ref>

Serotonin serves as a plant defense chemical against fungi. When infected with [[Fusarium crown rot of wheat|Fusarium crown rot]] (''Fusarium pseudograminearum''), [[wheat]] (''Triticum aestivum'') greatly increases its production of tryptophan to synthesize new serotonin.<ref name="Powell-et-al-2016">{{cite journal | vauthors = Powell JJ, Carere J, Fitzgerald TL, Stiller J, Covarelli L, Xu Q, Gubler F, Colgrave ML, Gardiner DM, Manners JM, Henry RJ, Kazan K | title = The Fusarium crown rot pathogen Fusarium pseudograminearum triggers a suite of transcriptional and metabolic changes in bread wheat (Triticum aestivum L.) | journal = Annals of Botany | volume = 119 | issue = 5 | pages = 853–867 | date = March 2017 | pmid = 27941094 | pmc = 5604588 | doi = 10.1093/aob/mcw207 | publisher = [[Oxford University Press]] (OUP) | s2cid = 3823345 | doi-access = free }}</ref> The function of this is poorly understood<ref name="Powell-et-al-2016" /> but wheat also produces serotonin when infected by ''[[Stagonospora nodorum]]'' – in that case to retard spore production.<ref name="Du-Fall-Solomon-2013">{{cite journal | vauthors = Du Fall LA, Solomon PS | title = The necrotrophic effector SnToxA induces the synthesis of a novel phytoalexin in wheat | journal = The New Phytologist | volume = 200 | issue = 1 | pages = 185–200 | date = October 2013 | pmid = 23782173 | doi = 10.1111/nph.12356 | publisher = [[Wiley-Blackwell|Wiley]] | doi-access = free | bibcode = 2013NewPh.200..185D }}</ref> The model [[cereal]] ''[[Brachypodium distachyon]]'' – used as a research substitute for wheat and other production cereals – also produces serotonin, [[coumaroyl]]-serotonin, and [[feruloyl]]-serotonin in response to ''[[Fusarium graminearum|F. graminearum]]''. This produces a slight [[antimicrobial]] effect. ''B.&nbsp;distachyon'' produces more serotonin (and conjugates) in response to [[deoxynivalenol]] (DON)-producing ''F. graminearum'' than non-DON-producing.<ref name="Pasquet-et-al-2014">{{cite journal | vauthors = Pasquet JC, Chaouch S, Macadré C, Balzergue S, Huguet S, Martin-Magniette ML, Bellvert F, Deguercy X, Thareau V, Heintz D, Saindrenan P, Dufresne M | title = Differential gene expression and metabolomic analyses of Brachypodium distachyon infected by deoxynivalenol producing and non-producing strains of Fusarium graminearum | journal = BMC Genomics | volume = 15 | issue = 1 | pages = 629 | date = July 2014 | pmid = 25063396 | pmc = 4124148 | doi = 10.1186/1471-2164-15-629 | publisher = [[BioMed Central]] | doi-access = free }}</ref> ''[[Solanum lycopersicum]]'' produces many [[amino acid|AA]] conjugates – including several of serotonin – in its leaves, stems, and roots in response to ''[[Ralstonia solanacearum]]'' infection.<ref name="Zeiss-et-al-2021">{{cite journal | vauthors = Zeiss DR, Piater LA, Dubery IA | title = Hydroxycinnamate Amides: Intriguing Conjugates of Plant Protective Metabolites | journal = Trends in Plant Science | volume = 26 | issue = 2 | pages = 184–195 | date = February 2021 | pmid = 33036915 | doi = 10.1016/j.tplants.2020.09.011 | publisher = [[Cell Press]] | bibcode = 2021TPS....26..184Z | s2cid = 222256660 }}</ref>

Serotonin occurs in several hallucinogenic mushrooms of the genus ''[[Panaeolus]]''.<ref name="Tyler1958">{{cite journal | vauthors = Tyler VE | title = Occurrence of serotonin in a hallucinogenic mushroom | journal = Science | volume = 128 | issue = 3326 | pages = 718 | date = September 1958 | pmid = 13580242 | doi = 10.1126/science.128.3326.718 | bibcode = 1958Sci...128..718T }}</ref>