richness and composition of decomposer organisms (Saikkonen et al. 2015 ). The
non-systemic endophytes from grasses and other plants are also survive in
decomposing plant litter as saprotrophs and endophytes, as they can play a role in
leaf senescence (Purahong and Hyde 2011 ). Systemic grass endophytes can
increase growth, reproduction and stress resistance of their host plant (Clay and
Hollah 1999 ) and thereby increase the amount of litter produced by the host. They
can affect the quality of plant litter by modulating the foliage quality of the host
plant.
The endophyte plant symbiosis produces various alkaloids such as pyrolizidines
(Lolines), ergot alkaloids, indolediterpenoides (including lolitrems), and the
pyrrolopyrazine alkaloids (Peramine) (Saikkonen et al. 2010 ; Schardl 2010 ) and
alter the concentration of sugars, water and modulates their oxidative balance,
phytohormone signalling and other metabolic pathways (Liu et al. 2011 ; Saikkonen
et al. 2013 ).
The host plants induce responses to invaders and attackers by two evolutionary
conserved phytohormone signalling pathways, i.e., by the salicylic acid (SA) and
jasmonic acid (JA) pathways (Pieterse and Dicke 2007 ). Plant defence responses to
bio trophic pathogens are mediated by SA pathways (Thaler et al. 2012 ).
Endophytes have both positive and negative effects of decomposer organisms
(Lemons et al. 2005 ). Saikkonen et al. ( 2013 ) proposed that endophytes similar to
that of the parasites likely induce SA pathway, thus suppressing the mutually
antagonistic JA pathway, which is mainly involved in the defence system against
pathogens and herbivores. Alternatively, the negative effects can arise prior to
colonization of the leaf litter and competitive exclusion of the saprophytic fungi.
The allelopathic chemicals produced by endophytes toxic to both microbial and
invertebrate decomposers would also lead to negative effects (Saikkonen et al.
2015 ). Endophytic fungi occur in various plant organs and have a close relationship
between hosts and soil (Sun et al. 2008 ; Chen and Dai 2013 ). Compounds released
as a result of endophytic plant symbiosis could decompose organic matter or inhibit
other microbial growth (Suberkropp and Weyers 1996 ). Endophytic fungi colo-
nizing the host roots could affect soil productivity by promoting soil nutrition
through decomposition and reduces soil heavy metal toxicity (Chen and Dai 2013 ).
Endophytic fungi also play an important role in the degradation of plant debris.
Oses et al. ( 2006 ) found that endophytic fungi belonged to basidiomycetes isolated
from Chilean tree speciesDrimys winteriandPrumnopitysandinawere able to
degrade the wood similar to white rot fungi. Endophytes from spruce needles
shown to pioneer decomposers in lab experiments (Muller et al. 2001 ). In a study
lignocellulolytic activity was observed fromAlternaria, PhomaandPhomopsis
isolated from surface sterilized pods ofColophospermum mopane(Jordaan et al.
2006 ; Wang and Dai 2011 ). A strain ofPhomopsissp., isolated from the inner bark
ofBischofia polycarpawas able to decompose pea nut straw (Shi et al. 2004 ).
A number of strains belonged to endophytic fungi such as Xylaria,
Geniculosporium, Coccomyces, Monotosporaproduced lignicellulolytic enzyme
activity (Koide et al. 2005 ; Osono and Takeda 2001 ).
52 Y.L. Krishnamurthy and B.S. Naik