The polyphenolic composition of 62 wild and weedy Mexican bean collections from diverse origins, grouped by their seed coat color, was assessed. According to spectrophotometric analysis, the range of total phenols, condensed tannins, and total anthocyanins presented wide differences. Furthermore, the phenolic acid, flavonoid, and anthocyanin profiles were analyzed using HPLC. Ferulic was the main phenolic acid. Kaempferol and quercetin were the main flavonoids, and the isoflavones daidzein and coumestrol were found in only low levels in few collections. Delphinidin was the main anthocyanidin found, followed by petunidin, cyanidin, malvidin, pelargonidin, and peonidin. The wide variation observed in polyphenolic contents was more related to their genotype than to the color factor. These results show that some wild and weedy beans are good sources of phenolic compounds for use in breeding programs focused on nutrition and health.

Soybean [Glycine max (L.) Merr.] seed isoflavone concentration 1999). Studies with humans (Crouse et al., 1999) and has been shown to be highly dependent on environmental conditions, monkeys (Anthony et al., 1997) show that isoflavonebut isoflavone concentrations have not been studied under controlled conditions to quantify the effects of specific factors. To determine rich soy protein isolates are more effective than purified the effect of air temperature and soil moisture status during soybean isoflavones for lowering blood cholesterol. The soybean seed development on seed isoflavone concentration and composition, isoflavones daidzein, genistein, and glycitein occur presoybean plants were grown in the greenhouse under intermediate dominantly as glucosides or malonylglucosides (Ohta et (18/28؇C), 9.5 h night/14.5 h daytime temperatures with high soil al., 1979) and are associated with the protein fraction moisture conditions. Beginning at the R6 growth stage plants were during processing. Due to the health benefits there is subjected to either intermediate (18/28؇C), low (13/23؇C), or high an increased interest in soy foods in the USA and other (23/33؇C) 9.5 h night/14.5 h daytime temperatures with either low or parts of the world. high soil moisture conditions. Two French cultivars, Imari and Queen, Several studies have shown that there is a large variaand three U.S. cultivars, Dwight, Jack and Loda, all in maturity group

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The composition and concentrations of cell wall polysaccharides and phenolic compounds were analyzed in mature stems of several Miscanthus genotypes, in comparison with switchgrass and reed (Arundo donax), and biomass characteristics were correlated with cell wall saccharification efficiency. The highest cellulose content was found in cell walls of M. sinensis 'Grosse Fontaine' (55%) and in A. donax (47%) and lowest (about 32%) in M. sinensis 'Adagio'. There was little variation in lignin contents across M. sinensis samples (all about 22-24% of cell wall), however, Miscanthus  giganteus (M  g) cell walls contained about 28% lignin, reed -23% and switchgrass -26%. The highest ratios of cellulose/lignin and cellulose/xylan were in M. sinensis 'Grosse Fontaine' across all samples tested. About the same total content of ester-bound phenolics was found in different Miscanthus genotypes (23-27 lg/mg cell wall), while reed cell walls contained 17 lg/mg cell wall and switchgrass contained a lower amount of ester-bound phenolics, about 15 lg/mg cell wall. Coumaric acid was a major phenolic compound ester-bound to cell walls in plants analyzed and the ratio of coumaric acid/ferulic acid varied from 2.1 to 4.3, with the highest ratio being in M  g samples. Concentration of ether-bound hydroxycinnamic acids varied greatly (about two-three-fold) within Miscanthus genotypes and was also the highest in M  g cell walls, but at a concentration lower than esterbound hydroxycinnamic acids. We identified four different forms of diferulic acid esters bound to Miscanthus cell walls and their concentration and proportion varied in genotypes analyzed with the 5-5-coupled dimer being the predominant type of diferulate in most samples tested. The contents of lignin and ether-bound phenolics in the cell wall were the major determinants of the biomass degradation caused by enzymatic hydrolysis.

Soybean hairy roots, transformed with the soybean chalcone synthase (CHS6) or isoflavone synthase (IFS2) genes, with dramatically decreased capacity to synthesize isoflavones were produced to determine what effects these changes would have on susceptibility to a fungal pathogen. The isoflavone and coumestrol concentrations were decreased by about 90% in most lines apparently due to gene silencing. The IFS2 transformed lines had very low IFS enzyme activity in microsomal fractions as measured by the conversion of naringenin to genistein. The CHS6 lines with decreased isoflavone concentrations had 5 to 20-fold lower CHS enzyme activities than the appropriate controls. Both IFS2 and CHS transformed lines accumulated higher concentrations of both soluble and cell wall bound phenolic acids compared to controls with higher levels found in the CHS6 lines indicating alterations in the lignin biosynthetic branch of the pathway. Induction of the soybean phytoalexin glyceollin, of which the precursor is the isoflavone daidzein, by the fungal pathogen Fusarium solani f. sp. glycines (FSG) that causes soybean sudden death syndrome (SDS) showed that the low isoflavone transformed lines did not accumulate glyceollin while the control lines did. The (iso)liquritigenin content increased upon FSG induction in the IFS2 transformed roots indicating that the pathway reactions before this point can control isoflavonoid synthesis. The lowest fungal growth rate on hairy roots was found on the FSG partially resistant control roots followed by the SDS sensitive control roots and the low isoflavone transformants. The results indicate the importance of phytoalexin synthesis in root resistance to the pathogen.

Understanding the metabolic responses of the plant to a devastating foliar disease, soybean rust, caused by Phakopsora pachyrhizi, will assist in development of cultivars resistant to soybean rust. In this study, differences in phenolic metabolism were analyzed between inoculated and noninoculated plants using two susceptible and three resistant soybean genotypes with known resistance genes. Rust infection resulted in increased accumulation of isoflavonoids and flavonoids in leaves of all soybean genotypes tested. Although the soybean phytoalexin glyceollin was not detected in leaves of uninfected plants, accumulation of this compound at marked levels occurred in rust-infected leaves, being substantially higher in genotypes with a red-brown resistant reaction. In addition, there was inhibition of P. pachyrhizi spore germination by glyceollin, formononetin, quercetin, and kaempferol. However, there was no correlation between concentrations of flavonoids quercetin and kaempferol and rust-induced isoflavonoid formononetin in soybean leaves and rust resistance. Lignin synthesis also increased in all inoculated soybean genotypes whereas there was no significant difference in all noninoculated soybean genotypes. Cell wall lignification was markedly higher in inoculated resistant lines compared with inoculated susceptible lines, indicating a possible protective role of lignin in rust infection development.

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.

BACKGROUND: Isoflavone content in soybean seeds is strongly influenced by both environment and genotype. However, little is known about the effect of environment and genotype on isoflavones in germ versus cotyledons. To determine the effect of temperature and soil moisture status during soybean seed development on seed isoflavone concentration and composition, a set of two French and three US cultivars of similar maturity were grown in the greenhouse. At the R6 growth stage, plants were subjected to one of three night/day temperature regimes (13/23• , 18/28• or 23/33• C) in either optimal or sub-optimal soil water conditions.