Explant types and auxins impact on callogenesis in medicinally important plant fenugreek: an in vitro study

Abstract Fenugreek (Trigonellafoenum-graecum L.), member of Fabacecae family, exists ubiquitously across the globe. For centuries, people have utilized this medicinal plant as a traditional food and medicine. It has been shown that fenugreek has hypoglycemic and hypocholesterolemic properties, among other health advantages. There is an increasing demand to ensure sustainable production for round-year propagation of this important medicinal plantenabling mass propagation to harness maximum therapeutic benefits of Fenugreek.The current study focuses on establishing ideal conditions of callus induction in Fenugreek as a foundationsteptowardmass propagation via callus culture.Differentexplant types and hormones with various concentrations were used for callogenesis under in vitroconditions.Initially, fenugreek seeds were cultivated on germination medium (MS-0) under in vitro conditions. After successful in vitro germination in aseptic conditions, three explants, viz. cotyledons, hypocotyl, and leaves were used as explants. For the callogenesis of these explants, callus induction medium (CIM) supplemented with auxins was used. For this purpose, varying levels (2mg L− 1, 3mg L− 1, and 4 mg L− 1) of 2,4-dichloro-phenoxyacetic acid (2,4-D) and naphthalene acetic acid (NAA) were used. Various parameters, including callus color, callus texture, days of callusing, percentage of callusing and callus index were used in the study. Our findings revealed that cotyledon superseded among different explants for callogenesis in response to phytohormones. Among various concentrations, 3 mg L− 1 was found to be optimum for callus color andtexture.For physiological parameters (days of callusing, percentage of callusing and callus index), 3 mg L− 1and4 mg L− 1proved to be optimal concentrations. The study unveiled ideal in vitro culture conditions of fenugreek plant, opening the door to the year-round isolation of essential bioactive compounds independent of the plant growing season. It also provided insights to exploring the role of reactive oxygen species (ROS) under higher concentrations of phytohormones. The approach is promising in achieving mass propagation of pharmacologically important plants in a cost-effective sustainable manner.