Response of Soybean Pathogens to Glyceollin

Abstract

Plants recognize invading pathogens and respond biochemically to prevent invasion or inhibit colonization in plant cells. Enhancing this response in crop plants could improve sustainable methods to manage plant diseases. To enhance disease resistance in soybean, the soybean phytoalexin glyceollin was assessed in soybean hairy roots of two soybean genotypes, Spencer and PI 567374, transformed with either soybean isoflavone synthase (IFS2) or chalcone synthase (CHS6) genes that were inoculated with the soybean pathogens Diaporthe phaseolorum var. meridionales, Macrophomina phaseolina, Sclerotinia sclerotiorum, and Phytophthora sojae. The hairy-root-transformed lines had several-fold decreased levels of isoflavone daidzein, the precursor of glyceollin, and considerably lower concentrations of glyceollin induced by pathogens measured 5 days after fungal inoculation compared with the nontransformed controls without phenolic transgenes. M. phaseolina, P. sojae, and S. sclerotiorum grew much more on IFS2- and CHS6-transformed roots than on control roots, although there was no significant difference in growth of D. phaseolorum var. meridionales on the transformed hairy-root lines. In addition, glyceollin concentration was lower in D. phaseolorum var. meridionales-inoculated transformed and control roots than roots inoculated with the other pathogens. Glyceollin inhibited the growth of D. phaseolorum var. meridionales, M. phaseolina, P. sojae, S. sclerotiorum, and three additional soybean pathogens: Cercospora sojina, Phialophora gregata, and Rhizoctonia solani. The most common product of glyceollin conversion or degradation by the pathogens, with the exception of P. sojae, which had no glyceollin degradation products found in the culture medium, was 7-hydroxyglyceollin.

Identification of Quantitative Trait Loci Controlling Gene Expression during the Innate Immunity Response of Soybean

“…MTI is characterized by a variety of plant responses, which include changes in ion flux across the plasma membrane, changes in cytoplasmic calcium levels, production of reactive oxygen species (ROS), callose deposition, modification of phytohormone concentrations, and induction or repression of different plant genes that condition antibiotic molecules, such as the phytoalexin glyceollin produced by soybean (Glycine max; Zipfel, 2009;Boudsocq et al, 2010;Lygin et al, 2010;Mersmann et al, 2010;Luna et al, 2011). These responses can be detected within minutes to hours after MAMP treatment, and the magnitude of the response may be plant-species dependent (Segonzac and Zipfel, 2011).…”

Cytochrome P₄₅₀, CYP93A1, as defense marker in soybean

“…This gene encodes a cytochrome P 450 (CYP) enzyme CYP93A1 that has dihydroxypterocarpan 6a-hydroxylase activity and is involved in the synthesis of the phytoalexin, glyceollin ). Glyceollin has anti-pathogen activity (Lygin et al 2010) and it has been associated with resistance against nematodes (Veech 1982). It also appears to function as a feeding deterrent against insects (Hart et al 1983, Liu et al 1992.…”

Are the Phytoestrogens Genistein and Daidzein Anti-Herbivore Defenses? A Test Using the Gypsy Moth (Lymantria dispar)

“…Numerous studies have demonstrated the role of phytoestrogens in attracting and promoting colonization by mutualistic bacteria (Schultze and Kondorosi, 1998;Makoi and Ndakidemi, 2007;Bhattacharya et al, 2010) and fungi (Requena et al, 2007;Badri et al, 2009). It is also well established that the phytoalexin glyceollin, for which daidzein is a precursor, is induced by and protects plants against fungal pathogens (Lozovaya et al, 2007;Jasinski et al, 2009;Lygin et al, 2010). However, the efficacy of phytoestrogens as anti-herbivore compounds is far less clear.…”