Effect of Elicitor Spray at Different Reproductive Stages on Saponin Content of Soybean

Abstract

The beneficial health effects of soybeans may be enhanced by increasing bioactive compounds including soyasaponins (ssp). The objective of this study is to elucidate the effect of elicitors sprayed on Ozark variety soybeans, on ssp content. Different concentrations of elicitors, ethyl acetate (EA) and methyl jasmonate (MJ), were sprayed at 4 different growth stages (1-bloom, 2-pod development, 3-seed development, and 4-seed maturity). Seeds were ground, defatted, ssp was extracted and identified and quantified with HPLC. Elicitor and growth stage had an effect on βg and βa contents of soybeans compared with control (P < 0.05). Elicitor had an effect on total ssp content (P < 0.001) and αg and γg content of soybeans compared with control (P < 0.05). Total ssp content of EA 0.05 M, MJ 0.001 M, and 0.005 M sprayed soybeans were higher than EA 0.001 M, which is higher than control (P < 0.05; 3.62, 3.56, 3.56, 3.29, and 2.98 μmol/g soybean, respectively). The overall effect of elicitor on total ssp content was not dependent on growth stage, however, elicitors sprayed at growth stages 1, 2, and 3 showed differences among elicitor applied soybeans. Elicitors applied at growth stage 4 did not have any effect on total ssp content compared to control. Elicitors EA 0.05 M, MJ 0.001, and 0.005 M can be applied on any growth stage to increase total saponin content of soybean variety Ozark. Higher saponin content may improve the beneficial health effects of soybean consumption.

Changes in the Levels of Off-Flavor Generation in Soybean through Biotic Elicitor Treatments

“…Hence, our study suggested that, for a given variety and elicitor, the concentration is an important factor for reduction of LOX2. Zhang et al while studying the effect of elicitor treatment on isoflavones also reported that, with all of the elicitors tested, concentration was a more important factor than growth stage Similarly, Eswaranandam et al reported that the overall effect of elicitor on total soy saponin content was not dependent on growth stage, however, elicitors sprayed at different growth stages showed differences among elicitors applied on soybeans.…”

“…Biotic elicitors (having biological origin) such as methyl jasmonate (MJ), salicylic acid (SA), etc. have been reported to increase production of secondary metabolites, isoflavonoid, betalain, saponin, and glucosinolates, through various mechanisms. They are natural plant growth regulator phytohormones playing key roles in the signal interplay during biotic and abiotic stresses .…”

Bridging the Gaps between Plant and Human Health: A Systematic Review of Soyasaponins

“…Stress-induced responses in plants are mediated by several signaling molecules, including redox molecules; Ca 2+ ; reactive oxygen species; MAP kinases; and phytohormones such as jasmonic acid (JA), salicylic acid (SA), abscisic acid (ABA), and ethylene (ETH) . Under biological stress by herbivores or pathogens, phytohormone signaling will trigger immune responses by activating changes in gene transcription to recruit antimicrobial proteins, callose proteins, secondary metabolites, or additional hormones to aid in plant defense. ,, In particular, research aimed at investigating metabolic regulation of triterpene saponin biosynthesis has focused on transcription factors upregulated via the phytohormones jasmonate (JA) ,,, and methyl jasmonate (MeJA), ,− although other phytohormones (SA, ETH, and ABA) can also enhance saponin yields to some degree . Having been studied in various systems (whole plants, cell culture, and root tissues), JA- and MeJA-induced synthesis of triterpene saponins has been documented in multiple legume species (Glycyrrhiza glabra, Glycyrrhiza uralensis, Medicago truncatula, Medicago sativa, and Glycine max). − Specifically, MeJA-induced soyasaponin synthesis enhances soyasaponin content in soybean seeds sprayed with MeJA during seed reproductive stages, in barrel medic cell cultures (soyasapogenols B and E), , and in licorice (Glycyrrhiza glabra) cell cultures (soyasapogenols B and E, soyasaponins). , Additionally, β-amyrin synthase (βAS), a key enzyme in oleanane triterpenoid saponin synthesis, is upregulated in response to MeJA in barrel medic cell cultures − and in licorice cell cultures, root nodules, and germinating seeds .…”

“…49 Having been studied in various systems (whole plants, cell culture, and root tissues), JA-and MeJA-induced synthesis of triterpene saponins has been documented in multiple legume species (Glycyrrhiza glabra, Glycyrrhiza uralensis, Medicago truncatula, Medicago sativa, and Glycine max). 56−61 Specifically, MeJA-induced soyasaponin synthesis enhances soyasaponin content in soybean seeds sprayed with MeJA during seed reproductive stages, 58 in barrel medic cell cultures (soyasapogenols B and E), 54,56 and in licorice (Glycyrrhiza glabra) cell cultures (soyasapogenols B and E, soyasaponins). 60,61 Additionally, βamyrin synthase (βAS), a key enzyme in oleanane triterpenoid saponin synthesis, is upregulated in response to MeJA in barrel medic cell cultures 54−56 and in licorice cell cultures, root nodules, and germinating seeds.…”

Agriculture and Bioactives: Achieving Both Crop Yield and Phytochemicals

“…Flavonoid concentration was also increased by 31% and 33% after 10 μM MeJA and 100 μM SA treatments, respectively in seven day old broccoli sprouts [120]. The application of ethyl acetate 0.05 M, MJ 0.001 and 0.005 M can be used at any growth stage to increase the total saponin content of soybean variety Ozark [121]. Puthusseri et al [122] informed that foliar applications of salicylic acid (250 μM) in Coriandrum sativum L. enhanced folate levels twofold (3112.33 μg/100 g DW).…”