Root Interactions in a Maize/Soybean Intercropping System Control Soybean Soil-Borne Disease, Red Crown Rot

Abstract

BackgroundWithin-field multiple crop species intercropping is well documented and used for disease control, but the underlying mechanisms are still unclear. As roots are the primary organ for perceiving signals in the soil from neighboring plants, root behavior may play an important role in soil-borne disease control.Principal FindingsIn two years of field experiments, maize/soybean intercropping suppressed the occurrence of soybean red crown rot, a severe soil-borne disease caused by Cylindrocladium parasiticum (C. parasiticum). The suppressive effects decreased with increasing distance between intercropped plants under both low P and high P supply, suggesting that root interactions play a significant role independent of nutrient status. Further detailed quantitative studies revealed that the diversity and intensity of root interactions altered the expression of important soybean PR genes, as well as, the activity of corresponding enzymes in both P treatments. Furthermore, 5 phenolic acids were detected in root exudates of maize/soybean intercropped plants. Among these phenolic acids, cinnamic acid was released in significantly greater concentrations when intercropped maize with soybean compared to either crop grown in monoculture, and this spike in cinnamic acid was found dramatically constrain C. parasiticum growth in vitro.ConclusionsTo the best of our knowledge, this study is the first report to demonstrate that intercropping with maize can promote resistance in soybean to red crown rot in a root-dependent manner. This supports the point that intercropping may be an efficient ecological strategy to control soil-borne plant disease and should be incorporated in sustainable agricultural management practices.

Physiological response and sulfur metabolism of the V. dahliae-infected tomato plants in tomato/potato onion companion cropping

“…For example, root interactions between maize and soybean increase the resistance of soybean to Cylindrocladium parasiticum 10, and maize and pepper interactions enhance maize resistance to Bipolaris maydis 9. Similarly, in a previous study, we have shown that tomato and potato onion interactions enhance tomato resistance to V. dahliae by up-regulating disease resistance-related genes under the tomato/potato onion companion cropping5.…”

“…These strategies would lower production costs and reduce environmental pollution. Several studies have demonstrated that intercropping and companion cropping may alleviate soil-borne diseases by enhancing plant disease resistance to pathogens45910. Previous studies have shown that companion cropping with potato onions alleviates tomato Verticillium Wilt by up-regulating the expression levels of genes related to disease resistance (encoding proteins such as pathogenesis-related proteins and those involved in lignin biosynthesis, phytohormone metabolism and signal transduction) in tomatoes infected with V. dahliae 5, and by the inhibition effect of tomato root exudates on V. dahliae .…”

Eight principles of integrated pest management

“…Similar patterns have been reported for composite cross-populations of barley (Saghai Maroof et al 1983). Intercropping different crop species can be used to reduce severity of diseases (FernandezAparicio et al 2010;Gao et al 2014). In perennial systems, living mulches can be successfully established for the control of weeds (Baumgartner et al 2008;Fourie 2010).…”

Toward a Regional Phosphorus (Re)cycle in the US Midwest

“…4A, C), although significant declines in aboveground biomass occurred at higher proportions of P supplied as struvite. The strong crop species‐specific response to struvite and phytin is consistent with crop species differences in root exudate quantity and quality: maize root systems can secrete nearly threefold more exudate C than those of soybean (Gao et al, 2014; Guo et al, 2017). For phytin, no significant difference in aboveground biomass was found for up to 100 and 50% replacement of P as monoammonium phosphate (MAP) for maize and soybean, respectively (Fig.…”