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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Microbiol. | doi: 10.3389/fmicb.2019.02671

Seasonal variation and crop sequences shape the structure of bacterial communities in cysts of soybean cyst nematode

  • 1University of Florida, United States
  • 2University of Minnesota Twin Cities, United States
  • 3Southern Research and Outreach Center, University of Minnesota, United States

Soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is the number one pathogen of the important economic crop soybean. Bacteria represent potential biocontrol agents of the SCN, but few studies have characterized the dynamics of bacterial communities associated with cysts under different crop rotation sequences. The bacterial communities in SCN cysts in a long-term soybean-corn crop rotation experiment were investigated over two years. The crop sequences included long-term soybean monoculture (Ss), years 1-5 of soybean following 5 years corn (S1-S5), years 1 and 2 of corn following 5 years soybean (C1 and C2), and soybean-corn annual rotation (Sa and Ca). The bacterial 16S rRNA V4 region was amplified from DNA isolated from SCN cysts collected in spring at planting, midseason (two months later), and fall at harvest and sequenced on the Illumina MiSeq platform. The SCN cyst microbiome was dominated by Proteobacteria followed by Actinobacteria, Bacteroidetes, and Verricumicrobia. The bacterial community composition was influenced by both crop sequence and season. Although differences by crop sequence were not highly significant in the spring of each year, bacterial communities in cysts from annual rotation (Sa and Ca) or crop sequences of early years of monoculture following a five year rotation of the alternate crop (S1 and C1) became rapidly differentiated by crop over a single growing season. In the fall, genera of cyst bacteria associated with soybean crop sequences included Rhizobacter, Leptothrix, Cytophaga, Chitinophaga, Niastella, Streptomyces, and Halangium. The discovery of diverse bacterial taxa in SCN cysts and their dynamics across crop rotation sequences provides invaluable information for future development of biological control of the SCN.

Keywords: bacterial community, biological control, Crop rotation, metabarcoding, next generation sequencing, Soybean cyst nematode (Heterodera glycines) (SCN)

Received: 12 Aug 2019; Accepted: 04 Nov 2019.

Copyright: © 2019 Hu, Strom, Haarith, Bushley and Chen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Mx. Kathryn Bushley, University of Minnesota Twin Cities, St. Paul, 55108, Minnesota, United States, kbushley@umn.edu