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Abstract

The ability of the stink bug (Nezara viridula) to induce and/or increase production of chemical defenses, i.e., flavonoids, in immature seeds of five genotypes of soybean (BR-16, IAC-100, PI 227687, PI 229358, and PI 274454) was investigated under greenhouse and laboratory conditions. Samples from pods of each genotype damaged by stink bug were analyzed for flavonoid content with high performance liquid chromatography. A dual-choice test was conducted to evaluate the feeding preference of N. viridula comparing BR-16 pods treated with extracts of PI 227687 seeds (with and without stink-bug injury), with water-treated pods. Seeds of PI 227687 damaged by N. viridula presented the highest concentration (352 microg/g) of daidzin (4'-hydroxyisoflavone-7-glucoside). The same trend was observed with genistin (4',5,7-trihydroxyisoflavone-7-glucoside): PI 227687 contained 142.4 microg/g, PI 274454,31,6 microg/g, and PI 229358,38.9 microg/g. Seeds damaged by stink bugs had higher isoflavone contents (daidzin and genistin), compared to controls. However, after being damaged, PI 274454 and PI 229358 produced less genistin than the other genotypes and no differences in concentration between damaged and nondamaged plants of this genotypes were observed. The numbers of observations of the insect feeding and the numbers of stylet sheaths left in water-treated BR-16 pods were greater than in those treated with PI 227687 extracts. The insects fed for longer periods on BR-16 pods treated with extract of PI 227687 without injury compared to those that were treated with extract of PI 227687 previously injured by stink bugs. Extracts of PI 227687 pods (damaged or not) were deterrent to adults of N. viridula, and insect injury increased concentrations of daidzin and genistin in PI 227687 seeds. The deterrence seemed to be more pronounced after pods had suffered stink-bug injury.

The natural plant stress elicitor cis-jasmone causes cultivar-dependent reduction in growth of the stink bug, Euschistus heros and associated changes in flavonoid concentrations in soybean, Glycine max

“…The performance of E. heros, measured by insect weight gain, on the resistant cultivar Dowling was negatively affected, suggesting that the treatment effect on pest development is cultivar-dependent. Previous experiments ( Piubelli et al., 2003a , Piubelli et al., 2005 ) provided evidence of a role for flavonoids in conferring soybean resistance to insect pests. Thus, it is hypothesized that cJ-induced changes in flavonoid production result in a cultivar-dependent reduced performance of stink bugs.…”

“…Of the twelve major known classes of flavonoids ( Harborne, 1989 ), in soybean there is a predominance of flavonols (kaempferol, quercetin and isorhamnetin) and isoflavones (daidzein, genistein and glycitein) and their glycosides. Flavonols and isoflavones are more prominent in vegetative and reproductive soybean stages respectively ( Song et al., 2014 ), and have been shown to play a role in protecting soybean against insects ( Hoffmann-Campo et al., 2001 , Hoffmann-Campo et al., 2006 , Piubelli et al., 2003a , Salvador et al., 2010 ) and pathogens ( Graham et al., 1990 , Graham and Graham, 1991 ).…”

“…This germplasm accession, together with PI 229358 and PI 171451, was described by Lambert and Kilen, 1984a , Lambert and Kilen, 1984b as resistant to several lepidopteran soybean insects. Furthermore, it was observed that daidzein and genistin concentrations increased in soybean seeds of PI 227697 upon damage by Nezara viridula stink bugs, provoking adverse effects on insect feeding preference ( Piubelli et al., 2003a ). An increase in the content of isoflavones was also observed for soybean pods exposed to solar UV-B radiation by Zavala et al.…”

Insect-Induced Daidzein, Formononetin and Their Conjugates in Soybean Leaves

“…In a similar fashion, insect damage in cruciferous plants results in the myrosinase mediated hydrolysis of glucosinolates to produce highly toxic isothiocyanates that deter non-adapted herbivores [ 17 , 18 ]. Upon damage to developing seeds caused by southern green stink bug ( Nezara viridula ) feeding, multiple soybean genotypes locally accumulate elevated levels of flavonoids including daidzin and genistin [ 19 ]. Outside of this investigation in seed pods, the dynamics of insect-inducible metabolites in soybean leaves remain poorly understood.…”

Determination of Agronomical Characters as the Resistance Attributes of Twenty Soybean Varieties to Stink Bug (Nezara viridula L.)

“…Antixenosis mechanisms have been reported, such as pod hardness (Silva, Baldin, Canassa, Souza, & Lourenção, 2014), the rigid epidermis of the pod (de Santana Souza, Lopes Baldin, da Silva, & Lourenção, 2013), cell walls hardness of seed (Giacometti, Ilina, Eduardo, & Zavala, 2018), and trichome densities (Nomayanja, Tukamuhubwa, & Kyamanywa, 2000). Antibiosis mechanisms also have been reported, such as daidzin and genistin content in pods (Zavala, Mazza, Dillon, Chludil, & Ballaré, 2015) and daidzin and genistin content seed (Piubelli, Hoffmann-Campo, De Arruda, Franchini, & Lara, 2003), and flavonoids content in immature seeds (da Graça et al, 2016;Piubelli, Hoffmann-Campo, De Arruda, Franchini, & Lara, 2003).…”