<p>Arbuscular mycorrhizal
fungi (AMF) are best known for their potential to help plants acquire
nutrients, especially phosphorous. These microbes improve soil health by
promoting soil aggregation and carbon sequestration, and further benefit plants
by helping them withstand biotic and abiotic stress. Currently, there are 200
recognized species of AMF within the phylum Glomeromycota. Recent studies
indicate that individual AMF species differ in the benefits they provide, with
some even acting as parasites. Moreover, AMF community composition can be
altered by soil and crop management practices, but the effect of these changes
on the benefits conferred by AMF are still not well understood. Consequently,
the goal of this study was to determine how two widely used crop management
systems can alter the composition of AMF species, and affect the potential for
these communities to promote the productivity and drought tolerance. To
accomplish this goal, we collected AMF inoculum from a long-term crop systems
trial comparing organic and conventional management for use in greenhouse
trials where we subjected plants to drought. We collected AMF inoculum during
mid-summer when differences between the two management systems were likely
cause larger effects on AMF communities, and again in autumn after harvest to
see if differences in AMF communities would persist. We determined AMF species
composition using next generation sequencing. Results of this study confirm
that soil-building practices commonly used in organic farming systems can
improve soil health and increase the productivity of food-grade soybeans. They
also demonstrate that AMF communities in Indiana croplands are highly diverse,
and some of these taxa can improve soybean growth and help plants tolerate
water stress. Although the overall diversity of AMF communities did not differ
between the organic and conventional management systems in mid-summer,
individual AMF taxa did differ between the systems, which were likely
responsible for the greater tolerance to water stress observed when plants were
amended with inoculum from the organic system. AMF communities present during
autumn were significantly different between the two crop management systems,
but did not result in differences in drought tolerance of soybeans, indicating
that the loss of key AMF taxa in the organic system from the first relative to
the second experiment was likely responsible. Finally, plants grown using
inoculum from both crop management systems in autumn had greater tolerance to
water stress than plants that received a AMF commercial inoculum. This provides
further evidence that individual AMF species vary in the benefits they provide,
and that the presence of a diverse consortium of AMF species is needed to
optimize plant health and productivity in agricultural systems. Agricultural
producers should consider incorporating soil-building practices that are
commonly used in organic farming systems such as planting winter cover crops,
to improve the health of their soil and enhance the productivity of their
crops. <b></b></p>
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| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/7493744 |
| Date | 03 January 2019 |
| Creators | Lisseth Zubieta (5930507) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Arbuscular_mycorrhizal_fungi_crop_management_systems_alter_community_structure_and_affect_soybean_growth_and_tolerance_to_water_stress/7493744 |
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