Involved in the biosynthesis of phenolic monoterpenes natural products thymol and carvacrol which have a broad range of biological activities acting as antimicrobial compounds, insecticides, antioxidants and pharmaceutical agents (PubMed:26750479). Monoterpene synthase which catalyzes the conversion of geranyl diphosphate (GPP) to gamma-terpinene and the minor products alpha-thujene, alpha-terpinene, myrcene, sabinene, (+)-R-limonene, alpha-pinene and alpha-phellandrene (PubMed:26750479). (2E)-geranyl diphosphate = diphosphate + gamma-terpinene (2E)-geranyl diphosphate = alpha-terpinene + diphosphate Binds 3 Mg(2+) or Mn(2+) ions per subunit. Secondary metabolite biosynthesis; terpenoid biosynthesis. Homodimer. Mostly expressed in flowers and, to a lower extent, in leaves, especially in glandular trichomes. Induced by jasmonic acid (MeJA), salicylic acid (SA) and UV-C irradiation. The Asp-Asp-Xaa-Xaa-Asp/Glu (DDXXD/E) motif is important for the catalytic activity, presumably through binding to Mg(2+). The monoterpenic phenol thymol is widely used as a fragrance and a flavoring ingredient in food and cosmetic industries (PubMed:29785774). Its derivatives have also several biological and pharmacological properties such as antimicrobial, antioxidant, anticarcinogenesis, anti-inflammatory and antispasmodic activities (PubMed:29785774, PubMed:29874939). Medical applications include the treatment of disorders affecting the respiratory, nervous, and cardiovascular systems (PubMed:29785774). It may also act as a growth enhancer and immunomodulator (PubMed:29785774). Thymol may also have antiviral activity toward COVID-19 by binding to the S1 receptor binding domain of the SARS-CoV-2 spike (S) glycoprotein (PubMed:32834111, PubMed:33855010). The monoterpenic phenol carvacrol is commonly used as a fragrance and a food flavoring ingredient and preservative (PubMed:24915411). Its derivatives exhibit also various biological and pharmacological properties including antioxidant, antibacterial, antifungal, insecticid, nematicid, anticancer, anti-inflammatory, hepatoprotective, spasmolytic, and vasorelaxant (PubMed:24915411, PubMed:29874939, PubMed:30836858, PubMed:33664752). Phytochemical inhibitor targeting the main SARS-CoV-2 viral protease (Mpro) and ACE2 in human host cells, carvacrol is a possible candidate for treating COVID-19 (PubMed:33664752, PubMed:32448034). Carvacrol may also have antiviral activity toward COVID-19 by binding to the S1 receptor binding domain of the SARS-CoV-2 spike (S) glycoprotein (PubMed:32834111, PubMed:33855010). Belongs to the terpene synthase family.