Multiple shoot regeneration, establishment of callus and cell suspension cultures in Salacia macrosperma Wight

Abstract

Salacia macrosperma Wight. -a potent medicinal plant facing the verge of rare and endemic status to the Western Ghat of southern India. Effective protocol has been established for induction of callus and multiple shoot regeneration using leaf and nodal explants on MS medium fortified with various plant growth regulators like 2,4-dichlorophenoxyacetic acid (2,4-D), benzyl amino purine (BAP), thidiazuron (TDZ), Indole acetic acid (IAA), Kinetin (Kn), Naphthalene acetic acid (NAA) and Indole butyric acid (IBA). Leaf explants produced more calli (98.33%) than nodal explants at 2.5 + 1.5 mg L -1 of 2, 4-D and BAP in combination. MS medium with 1.5 mg L -1 of 2, 4-D, 2.0 mg L -1 of BAP and 1.5 mg L -1 of TDZ along with 1% activated charcoal was apt for multiple shoot regenerations (93.33%) from nodal explants with embryogenic callus. Rhizogenesis was achieved in liquid MS medium supplemented with 1.0 mg L -1 of IAA. Friable callus when agitated in liquid MS medium at 100 rpm embryogenic callus followed by morphological changes were observed. Cytogenetic variations such as multinucleate, multinucleolate, cytodifferentiation, chromosomal bridges were noticed, besides normal dividing stages. Anatomical features were observed by microtome sections of the embryogenic callus revealed the presence of active centers, embryoids, and shoot bud formation. Further, by scanning electron micrograph (SEM) analysis of embryogenic callus different stages of morphogenic developmental features were recorded.

Salacia spp.: recent insights on biotechnological interventions and future perspectives

“…Mahendra et al ( 2020b ) achieved callus production in 98.33% of culture vessels when leaf segments of S. macrosperma were transferred to MS medium with 2,4-D (2.5 mg/l) and BAP (1.5 mg/l). The same observation was recorded in further studies of S. macrosperma (Mahendra et al 2020a ). The pro-embryos were developed in 60% liquid cultures from leaf-derived calli.…”

“…An attempt at in vitro culture establishment in Salacia spp. was made using nodal segments, especially in the cultures that were initiated for shoot multiplication and propagation purposes (Sasidharan et al 2010 ; Dhanasri et al 2013 ; Chavan et al 2015b ; Deepak et al 2015b ; Majid et al 2017 , 2018 ; Laxmi et al 2018 ; Kamat et al 2021 ; Mahendra et al 2020a ). However, diverse surface sterilization procedures have been employed for different Salacia spp.…”

“…Most of the nodal explants cleaned undergoing tap water wash followed by immersion in different types of detergents. Mercuric chloride is a monotonous surface disinfectant used for sterilizing the nodal explants of S. chinensis (Majid et al 2014 ; Chavan et al 2015b ; Laxmi et al 2018 ; Kamat et al 2021 ), S. macrosperma (Mahendra et al 2020a ), and S. oblonga (Deepak et al 2015b ), wherein sodium hypochloride has been used to disinfect nodal segments of S. reticulata (Dhanasri et al 2013 ) and S. chinensis (Majid et al 2016 , 2017 ). Shoot tip explants have also been tested for their efficiency during establishing in vitro cultures of S. chinensis (Majid et al 2016 , 2017 ), whereas in both attempts, the shoot tips were surface sterilized with sodium hypochloride.…”

“…Callus cultures of most of the Salacia spp. have been initiated using leaf explants (Chavan et al 2015b , 2021 , 2022 ; Majid et al 2017 ; Mahendra et al 2020a , b ; Kamat et al 2021 ), with a few exceptions such as node and shoot tip explants (Majid et al 2017 ; Mahendra et al 2020a ).…”

“…However, shoot multiplication from seed explants of S. chinensis was dependent on the addition of 2iP (2.0 mg/l) and BAP (3.0 mg/l) in MS medium (Kamat et al 2021 ). A mixture of BAP (1.0 mg/l), NAA (0.5 mg/l), and TDZ (0.5 mg/l) was found suitable for maximum shoot production in S. macrosperma (Mahendra et al 2020a ), wherein an average of 13.00 ± 0.57 shoots per explant have been produced. MS medium mixed with BAP (3.5 mg/l) and IBA (1 mg/l) was found suitable for shoot multiplication in S. oblonga (Deepak et al 2015b ).…”