plants were tested for their efficacy to tolerate 1, 2, 3, 5 and 7% of NaCl concen-
trations for 24 h. Interestingly, 3 of the isolates showed promising salt tolerance
under all the tested concentrations. As endophytes constantly maintain a mutualistic
association with plants, utilization of this symbiotic functional trait can be a
solution for plant adaptation to environmental stress like high salinity. The
plant-endophyte mutualistic association can, therefore, be utilized in conferring
stress tolerance to stress-sensitive species of plants. Moreover, the association can
also act as triggering factors to activate the stress responsive mechanisms in host
plants. Endophytes with such potential can thereby be an effective measure in
agricultural sectors conferring plant tolerance and adaptation to adverse conditions.
A more advanced biotechnological application could involve transformation and
cloning of stress tolerant genes into plant systems, albeit the environmental vari-
ables such as nutrition, pH, soil composition, associated microbial community,
plant metabolic processes, etc. might affect the success rate of such strategies.
Plant hormones such as auxins, cytokinins, abscisic acid, gibberellins and others
play an important role in regulation of plant cellular and metabolic processes,
development and growth. In general, auxins like IAA, indole-3-butyric acid
(IBA) and 2, 4-dichlorophenoxyacetic acid (2,4-D) are responsible for root elon-
gation and cytokinins like kinetin (Kin), 6-benzylaminopurine (BAP) and zeatin for
shoot formations (Sakakibara 2006 ; Blakeslee and Murphy 2016 ). The endophytic
bacteria isolated from roots ofCannabis plants were successful in producing
IAA-like molecules, which increased four folds when treated with tryptophan, the
precursor of IAA (Afzal et al. 2015 ). Furthermore, several isolates were able to
significantly increase root lengths of treatedCannbisplants. Interestingly, the plants
inoculated with endophytic bacterial isolates producing IAA-like molecule(s)
enhanced the lengths of roots when compared with non-inoculated plants. This
pointed towards the fact that root elongation was dependent on the production of
IAA by endophytes. Therefore, this study further highlighted an important bene-
ficial effect of endophytes in plant development and growth via production of plant
growth regulator-like molecules by the endophytes.
Research onCannabisplant tissue culture has garnered immense importance
owing to its utilization in plant biotechnology (Raharjo et al. 2006 ; Mustafa et al.
2011 ; Chandra et al. 2013 ; Chaohua et al. 2016 ). Several elicitation studies
involving combinations of callus cultures, fungal mycelia and growth regulators
like jasmonic and salicylic acid have also been reported (Flores-Sanchez et al.
2009 ). Therefore, intensive investigations in directions concerning plant tissue
culture and co-culture systems with beneficial endophytes can be an important
biotechnological advancement. Employing plant tissue culture techniques for
inoculating callus cultures or in vitro roots containing potent endophytic isolates
could be used to establish in vitro plant-endophyte mutualistic association taking
positive functional traits of endophytes into consideration, thereby improvising
plant growth and development. Additionally, using regenerated plants from tissue
cultures could serve as an alternative model for inoculation and interaction studies
of mature plants with beneficial endophytes. Moreover, performing elicitation
experiments with endophytes would enable evaluation of secondary metabolite
20 Cannabis Endophytes and Their Application... 427