Changes in light quality alter physiological responses of soybean to thiamethoxam
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The interaction between neighboring weed-induced far-red enriched light and thiamethoxam can significantly alter soybean seedling morphology, nodulation, isoflavone levels, UV-absorbing phenolics, and carbon and nitrogen content.
Neonicotinoid insecticides that are widely used on major crop plants can enhance plant growth and yield. Although the underlying mechanism of this enhanced growth and yield is not clear, recent studies suggest that neonicotinoids such as thiamethoxam (TMX) may exert their effects at least in part via signals that involve salicylic acid (SA) and jasmonic acid (JA). In the current research, effects of TMX on morphological and physiological responses of soybean have been compared under far-red-depleted (FR-D) and far-red-enriched (FR-E) light reflected by neighboring weeds. TMX significantly enhanced shoot and root growth but did not prevent stem elongation under FR-E light. Also, TMX did not prevent reductions in shoot carbon content and shoot carbon to nitrogen ratio under FR-E light. Despite similarities between these TMX effects in soybean and those known for SA and JA in other plant species, TMX significantly enhanced root-nodule numbers per plant and levels of root isoflavones malonyl-daidzin and malonyl-genistin under FR-E light only. These results suggest that the combined effect of FR-E light and TMX triggers a mechanism that operates concomitantly to enhance root isoflavones and nodulation in soybean.
KeywordsCarbon to nitrogen ratio Far-red light Isoflavones Neonicotinoids Nodulation Soybean-weed competition
Carbon to nitrogen ratio
Days after planting
High-performance liquid chromatography
Honestly significant difference
Isochorismate synthase 1
Photosynthetic photon flux density
Red to far-red ratio
This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC-CRD file no. CRDPJ 425128-11 to C.J.S.) and Syngenta Canada Inc. The authors express their appreciation to Harold Wright and Jonathon Roepke for their contributions throughout this study.
- Calafiori MH, Barbieri AA (2001) Effects of seed treatment with insecticide on the germination, nutrients, nodulation, yield and pest control in bean (Phaseolus vulgaris L.) culture. Ecossistema 26:97–104Google Scholar
- Casal JJ (2012) Shade avoidance. The Arabidopsis book 10:e0157Google Scholar
- Casal JJ (2013) Canopy light signals and crop yield in sickness and in health. ISRN Agron 2013:650439Google Scholar
- Cerrudo I, Keller MM, Cargnel MD, Demkura PV, de Wit M, Patitucci MS, Pierik R, Pieterse CM, Ballaré CL (2012) Low red/far-red ratios reduce Arabidopsis resistance to Botrytis cinerea and jasmonate responses via a COI1-JAZ10-dependent, salicylic acid-independent mechanism. Plant Physiol 158:2042–2052CrossRefPubMedPubMedCentralGoogle Scholar
- Dumas JB (1831) Sur les procédés de l’analyse organique. Ann Chim Phys 47:198–213Google Scholar
- Frak E, Le Roux X, Millard P, Adam B, Dreyer E, Escuit C, Sinoquet H, Vandame M, Varlet-Grancher C (2002) Spatial distribution of leaf nitrogen and photosynthetic capacity within the foliage of individual trees: disentangling the effects of local light quality, leaf irradiance, and transpiration. J Exp Bot 53:2207–2216CrossRefPubMedGoogle Scholar
- Hayat Q, Hayat S, Alyemeni MN, Ahmad A (2012) Salicylic acid mediated changes in growth, photosynthesis, nitrogen metabolism and antioxidant defense system in Cicer arietinum L. Plant Soil Environ 58:417–423Google Scholar
- Page ER, Tollenaar M, Lee EA, Lukens L, Swanton CJ (2010) Shade avoidance: an integral component of crop-weed competition. Weed Res 50:281–288Google Scholar
- Suzuki A, Suriyagoda L, Shigeyama T, Tominaga A, Sasaki M, Hiratsuka Y, Yoshinaga A, Arima S, Agarie S, Sakai T, Inada S, Jikumaru Y, Kamiya Y, Uchiumi T, Abe M, Hashiguchi M, Akashi R, Sato S, Kaneko T, Tabata S, Hirsch AM (2011) Lotus japonicus nodulation is photomorphogenetically controlled by sensing the red/far red (R/FR) ratio through jasmonic acid (JA) signaling. Proc Natl Acad Sci USA 108:16837–16842CrossRefPubMedPubMedCentralGoogle Scholar