EIPF are commonly found in agricultural soils. In addition to research to understand underlying mechanisms of action for development of commercial products,
there are opportunities to develop strategies to conserve endemic EIPF. Future
research to understand the relevance of laboratory experiments to field settings
where the environment is more variable are needed to more fully understand the
role of EIPF in plant protection, growth promotion, and nutrient exchange in
agricultural production systems, and if they can be used to benefit crop production
in agroecosystems. We know relatively little about how EIPF–plant–stress
interactions determine the frequency, specificity, and extent of EIPF–plant
associations, their effects on plant growth promotion, and the persistence of these
effects on crop plants in the field. Research on the influence of abiotic and biotic
factors on the prevalence and recruitment of endophytes in general, and EIPF, in
particular is needed because plant and soil characteristics vary in their ability to be
managed. Farming practices that support beneficial rhizosphere and endophytic
fungi could benefit crop yields and suppress pests. For example, if factors related
to crop species or variety drive recruitment or conservation of EIPF, then plants with
those characteristics could be used or bred into crops. Even though EIPF appear to
confer many benefits in crop production, more research is needed to assess the risks
for EIPF to cause damage to crops, including yield loss, and the environment,
including risk of non-target effects (Seiedy et al. 2015). EIPF produce secondary
metabolites that may be helpful in enhancing insect pathogenicity and in facilitating
endophytic interaction with plants (Fan et al. 2017), but there is potential for
development of EIPF beyond agriculture; for example, in medicine. The ecological
roles of EIPF remain elusive and need further research in the field. Better understanding of the ecology and biology of EIPF and their association with plants will
help achieve sustainable agriculture goals.
Acknowledgements This work was funded by USDA National Institute of Food and Agriculture,
Organic Transitions (ORG) (No. 2016-51106-25715 and No. 2019-51106-30198), and Organic
Farming Research Foundation (No. 232490).
Conflict of Interests The authors have no conflict of interests.
References
Acevedo FE, Rivera-Vega LJ, Chung SH, Ray S, Felton GW (2015) Cues from chewing insects—
the intersection of DAMPs, HAMPs, MAMPs and effectors. Curr Opin Plant Biol 26:80–86
Ahern JR, Whitney KD (2014) Stereochemistry affects sesquiterpene lactone bioactivity against an
herbivorous grasshopper. Chemoecology 24:35–39
Ahmad I, Zaib S (2020) Mighty microbes: plant growth promoting microbes in soil health and
sustainable agriculture. In: Giri B, Varma A (eds) Soil health. Springer, Berlin, pp 243–264
Ahmad I, Jiménez-Gasco MM, Luthe DS, Barbercheck ME (2020a) Systemic colonization by
Metarhizium robertsii enhances cover crop growth. J Fungi 6:64
Ahmad I, Jiménez-Gasco MM, Luthe DS, Shakeel SN, Barbercheck ME (2020b) Endophytic
Metarhizium robertsii promotes maize growth, suppresses insect growth, and alters plant
defense gene expression. Biol Control:104167
392
I. Ahmad et al.
there are opportunities to develop strategies to conserve endemic EIPF. Future
research to understand the relevance of laboratory experiments to field settings
where the environment is more variable are needed to more fully understand the
role of EIPF in plant protection, growth promotion, and nutrient exchange in
agricultural production systems, and if they can be used to benefit crop production
in agroecosystems. We know relatively little about how EIPF–plant–stress
interactions determine the frequency, specificity, and extent of EIPF–plant
associations, their effects on plant growth promotion, and the persistence of these
effects on crop plants in the field. Research on the influence of abiotic and biotic
factors on the prevalence and recruitment of endophytes in general, and EIPF, in
particular is needed because plant and soil characteristics vary in their ability to be
managed. Farming practices that support beneficial rhizosphere and endophytic
fungi could benefit crop yields and suppress pests. For example, if factors related
to crop species or variety drive recruitment or conservation of EIPF, then plants with
those characteristics could be used or bred into crops. Even though EIPF appear to
confer many benefits in crop production, more research is needed to assess the risks
for EIPF to cause damage to crops, including yield loss, and the environment,
including risk of non-target effects (Seiedy et al. 2015). EIPF produce secondary
metabolites that may be helpful in enhancing insect pathogenicity and in facilitating
endophytic interaction with plants (Fan et al. 2017), but there is potential for
development of EIPF beyond agriculture; for example, in medicine. The ecological
roles of EIPF remain elusive and need further research in the field. Better understanding of the ecology and biology of EIPF and their association with plants will
help achieve sustainable agriculture goals.
Acknowledgements This work was funded by USDA National Institute of Food and Agriculture,
Organic Transitions (ORG) (No. 2016-51106-25715 and No. 2019-51106-30198), and Organic
Farming Research Foundation (No. 232490).
Conflict of Interests The authors have no conflict of interests.
References
Acevedo FE, Rivera-Vega LJ, Chung SH, Ray S, Felton GW (2015) Cues from chewing insects—
the intersection of DAMPs, HAMPs, MAMPs and effectors. Curr Opin Plant Biol 26:80–86
Ahern JR, Whitney KD (2014) Stereochemistry affects sesquiterpene lactone bioactivity against an
herbivorous grasshopper. Chemoecology 24:35–39
Ahmad I, Zaib S (2020) Mighty microbes: plant growth promoting microbes in soil health and
sustainable agriculture. In: Giri B, Varma A (eds) Soil health. Springer, Berlin, pp 243–264
Ahmad I, Jiménez-Gasco MM, Luthe DS, Barbercheck ME (2020a) Systemic colonization by
Metarhizium robertsii enhances cover crop growth. J Fungi 6:64
Ahmad I, Jiménez-Gasco MM, Luthe DS, Shakeel SN, Barbercheck ME (2020b) Endophytic
Metarhizium robertsii promotes maize growth, suppresses insect growth, and alters plant
defense gene expression. Biol Control:104167
392
I. Ahmad et al.