and applications in sustainable agriculture are important areas of research on
endophytes producing a plethora of secondary metabolites and growth promoting
substances of diverse chemical nature from wide variety of species of plants and
endophytes. Endophytes have been reported from various crop plants, grasses, tree
species, and several other plants. It is envisioned that plants of extreme habitat such
as cold and hot conditions, carnivores of marshy lands, and all sorts of parasites
should be explored tofind out more diverse endophytes and hitherto lesser known
properties and metabolites. This might increase the inventory of useful metabolites.
Involvement of endophytes has also been evaluated infields as diverse as phy-
toremediation and biofuels production. Very limited options are available for
treating polluted water from agriculture and landfills. This area needs more attention
to use endophytes for developing this technology (Redfern Lauren and Gunsch
Claudia 2016 ).
Endophyte and host relationship is complex and not clearly understood. This
creates a further complex situation when a pathogen is present in the same host
plant. Cell-to-cell communication between different entities is not clearly under-
stood and this area will provide more understanding about the complex relationship,
which may provide clue for novel traits for plant breeding.
Reduction in dependence on chemical pesticides and fertilizers for sustainable
agriculture is an important area to meet the food security. Endophytes are beneficial
to crops directly by producing growth promoting compounds or indirectly by
inhibiting the growth of pathogens (Passari et al. 2016 ). Therefore, it is necessary to
characterize the endophytes and their products for crop improvement and sustain-
able environment. Their effective use will reduce the dependence on chemical
fertilizers and pesticides (Le Cocq et al. 2016 ).
Symbiotic nitrogenfixing endophytes is important class of endophytes studied in
great detail in leguminous plants and trees. Efforts to transfernifgene to non-
leguminous plants were not successful. In this case also, characterisation of
endophytes using genomics and tools of molecular biology would result useful
information. Characterization of endophytic bacterial and fungal endophytes will
also help infinding non-native hosts. Internal transcribed spacer (ITS) barcoding
along with classical taxonomic characterization are important areas of research on
endophytes (Tanney et al. 2016 ). Characterization of endophytes using genomic
tools can help infinding more bacterial biocontrol agents and understanding the
mechanism of action (Eljounaidi et al. 2016 ).
All microorganisms, pathogenic, non-pathogenic and endophytes, produce var-
ious types to enzymes to dissolve host cell wall and other barriers to establish
themselves. These enzymes are useful in many scientific and industrial processes
and thus are explored for their optimum production system (Goyal et al. 2017 ).
Mycorrhyzal fungi occur as ecto- or endo-mycorrhyza in plant roots and recognized
as phosphate solubilising fungi. In light of recent works these fungi need to work
out for many more plant beneficial traits. This will benefit plant as well as
ecosystem.
Production of secondary metabolites of interest to pharmaceutical industry is
very attractivefield of research using biotechnological methods of plant cell
284 K.G. Ramawat