TY - JOUR
T1 - Nutrition vs association
T2 - plant defenses are altered by arbuscular mycorrhizal fungi association not by nutritional provisioning alone
AU - Stratton, Chase A.
AU - Ray, Swayamjit
AU - Bradley, Brosi A.
AU - Kaye, Jason P.
AU - Ali, Jared G.
AU - Murrell, Ebony G.
N1 - Funding Information:
This project was funded by USDA-NIFA #2018–67013-27402 and by generous private donations to The Land Institute.
Funding Information:
We would like to thank Alex Griffin, Konilo Zio, Blaze Johnson, Crystal Ma, and Hannah Shafer for their assistance with growing the plants and data collections, and Gary Felton for the use of his laboratory facilities for RNA analyses. All procedures were conducted in accordance to established guidelines for plant research by the IUCN and CITES.
Publisher Copyright:
© 2022, The Author(s).
PY - 2022/12
Y1 - 2022/12
N2 - Background: While it is known that arbuscular mycorrhizal fungi (AMF) can improve nutrient acquisition and herbivore resistance in crops, the mechanisms by which AMF influence plant defense remain unknown. Plants respond to herbivory with a cascade of gene expression and phytochemical biosynthesis. Given that the production of defensive phytochemicals requires nutrients, a commonly invoked hypothesis is that the improvement to plant defense when grown with AMF is simply due to an increased availability of nutrients. An alternative hypothesis is that the AMF effect on herbivory is due to changes in plant defense gene expression that are not simply due to nutrient availability. In this study, we tested whether changes in plant defenses are regulated by nutritional provisioning alone or the response of plant to AMF associations. Maize plants grown with or without AMF and with one of three fertilizer treatments (standard, 2 × nitrogen, or 2 × phosphorous) were infested with fall armyworm (Spodoptera frugiperda; FAW) for 72 h. We measured general plant characteristics (e.g. height, number of leaves), relative gene expression (rtPCR) of three defensive genes (lox3, mpi, and pr5), total plant N and P nutrient content, and change in FAW mass per plant. Results: We found that AMF drove the defense response of maize by increasing the expression of mpi and pr5. Furthermore, while AMF increased the total phosphorous content of maize it had no impact on maize nitrogen. Fertilization alone did not alter upregulation of any of the 3 induced defense genes tested, suggesting the mechanism through which AMF upregulate defenses is not solely via increased N or P plant nutrition. Conclusion: This work supports that maize defense may be optimized by AMF associations alone, reducing the need for artificial inputs when managing FAW.
AB - Background: While it is known that arbuscular mycorrhizal fungi (AMF) can improve nutrient acquisition and herbivore resistance in crops, the mechanisms by which AMF influence plant defense remain unknown. Plants respond to herbivory with a cascade of gene expression and phytochemical biosynthesis. Given that the production of defensive phytochemicals requires nutrients, a commonly invoked hypothesis is that the improvement to plant defense when grown with AMF is simply due to an increased availability of nutrients. An alternative hypothesis is that the AMF effect on herbivory is due to changes in plant defense gene expression that are not simply due to nutrient availability. In this study, we tested whether changes in plant defenses are regulated by nutritional provisioning alone or the response of plant to AMF associations. Maize plants grown with or without AMF and with one of three fertilizer treatments (standard, 2 × nitrogen, or 2 × phosphorous) were infested with fall armyworm (Spodoptera frugiperda; FAW) for 72 h. We measured general plant characteristics (e.g. height, number of leaves), relative gene expression (rtPCR) of three defensive genes (lox3, mpi, and pr5), total plant N and P nutrient content, and change in FAW mass per plant. Results: We found that AMF drove the defense response of maize by increasing the expression of mpi and pr5. Furthermore, while AMF increased the total phosphorous content of maize it had no impact on maize nitrogen. Fertilization alone did not alter upregulation of any of the 3 induced defense genes tested, suggesting the mechanism through which AMF upregulate defenses is not solely via increased N or P plant nutrition. Conclusion: This work supports that maize defense may be optimized by AMF associations alone, reducing the need for artificial inputs when managing FAW.
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U2 - 10.1186/s12870-022-03795-3
DO - 10.1186/s12870-022-03795-3
M3 - Article
C2 - 35974331
AN - SCOPUS:85136028271
SN - 1471-2229
VL - 22
JO - BMC plant biology
JF - BMC plant biology
IS - 1
M1 - 400
ER -