Teosinte (Zea mays ssp parviglumis) transcriptomic response to weed stress identifies similarities and differences between varieties and with modern corn varieties

Authors: BRUGGEMAN, STEPHANIE - South Dakota State University; Horvath, David; FENNELL, ANNE - South Dakota State University; GONZALEZ-HERNANDEZ, JOSE - South Dakota State University; CLAY, SHARON - South Dakota State University

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/3/2020
Publication Date: 8/21/2020
Citation: Bruggeman, S., Horvath, D.P., Fennell, A., Gonzalez-Hernandez, J., Clay, S.A. 2020. Teosinte (Zea mays ssp parviglumis) transcriptomic response to weed stress identifies similarities and differences between varieties and with modern corn varieties. PLoS One. 15(8):e0237715. https://doi.org/10.1371/journal.pone.0237715.
DOI: https://doi.org/10.1371/journal.pone.0237715

Interpretive Summary: Transcriptomic analyses are a major tool for identifying biological processes that control different aspects of how a plant grows and responds to stress. We used this tool to learn how teosinte, the weedy progenitor of modern corn, responds to interference from weeds in order to better understand the evolution of these responses in modern corn varieties. We determined that there were similarities such as enhanced defense signaling through the plant hormones salicylic and jasmonic acid, but that there were also differences such as enhanced secondary metabolic processes unique to teosinte. Future work will focus on transferring weed resistance mechanism discovered in teosinte to corn.

Technical Abstract: Transcriptomic responses of plants to weed presence gives insight on the physiological and molecular mechanisms involved in the stress response. This study evaluated transcriptomic responses of teosinte (Zea mayssspparviglumis) (an ancestor of domesticated maize) to weed presence over two growing seasons. Morphological and transcriptomic responses of two teosinte lines (Ames 21812 and Ames 21789) with and without weed presence were compared after 6 weeks of growth in Aurora, South Dakota, USA. Plant heights between treatments were similar in Ames 21812, whereas branch number decreased when weeds were present. Ames 21789 was 45% shorter in weedy vs seed-free plots, but branch numbers were similar between treatments. These observations suggest significant differences in response to interference exist in the progenitors of maize, and determination of the genes underlying these responses should be characterized in modern maize varieties. Season-long biomass accumulation in both lines was reduced in response to weed pressure. Common down-regulated subnetworks were related to light, photosynthesis, and carbon cycles. Several unique response networks (e.g. aging, response to chitin) and gene sets were present in each line. Comparing transcriptomic responses of maize (determined in an adjacent study) and teosinte lines indicated three common gene ontologies up-regulated in weed-stress response: jasmonic acid response/signaling, UDP-glucosyl and glucuronyltransferases, and quercetin glucosyltransferase (3-O and 7-O). Overall, morphologic and transcriptomic differences suggest a greater varietal (rather than a conserved) response to weed stress, and implies multiple responses are possible and offer insights into opportunities to define and manipulate these systems in modern maize varieties.