Non-targeted discovery of high-value bio-products in Nicotiana glauca L: a potential renewable plant feedstock.

The evaluation of plant-based feedstocks is an important aspect of biorefining. Nicotiana glauca is a solanaceous, non-food crop that produces large amounts of biomass and is well adapted to grow in suboptimal conditions. In the present article, compatible sequential solvent extractions were applied to N. glauca leaves to enable the generation of enriched extracts containing higher metabolite content comparing to direct leaf extracts. Typically, between 60 to 100 metabolite components were identified within the fractions. The occurrence of plant fatty acids, fatty acid alcohols, alkanes, sterols and terpenoids was detected by gas liquid chromatography-mass spectrometry (GC-MS) and metabolite identification was confirmed by comparison of physico-chemical properties displayed by available authentic standards. Collectively, co-products such waxes, oils, fermentable sugars, and terpenoids were all identified and quantified. The enriched fractions of N. glauca revealed a high level of readily extractable hydrocarbons, oils and high value co-products. In addition, the saccharification yield and cell wall composition analyses in the stems revealed the potential of the residue material as a promising lignocellulosic substrate for the production of fermentable sugars. In conclusion a multifractional cascade for valuable compounds/commodities has been development, that uses N. glauca biomass. These data have enabled the evaluation of N. glauca material as a potential feedstock for biorefining.

Effects of Sulfur Assimilation in Pseudomonas fluorescens SS101 on Growth, Defense, and Metabolome of Different Brassicaceae.

Genome-wide analysis of plant-growth-promoting Pseudomonas fluorescens strain SS101 (PfSS101) followed by site-directed mutagenesis previously suggested that sulfur assimilation may play an important role in growth promotion and induced systemic resistance in Arabidopsis. Here, we investigated the effects of sulfur metabolism in PfSS101 on growth, defense, and shoot metabolomes of Arabidopsis and the Brassica crop, Broccoli. Root tips of seedlings of Arabidopsis and two Broccoli cultivars were treated with PfSS101 or with a mutant disrupted in the adenylsulfate reductase cysH, a key gene in cysteine and methionine biosynthesis. Phenotyping of plants treated with wild-type PfSS101 or its cysH mutant revealed that sulfur assimilation in PfSS101 was associated with enhanced growth of Arabidopsis but with a reduction in shoot biomass of two Broccoli cultivars. Untargeted metabolomics revealed that cysH-mediated sulfur assimilation in PfSS101 had significant effects on shoot chemistry of Arabidopsis, in particular on chain elongation of aliphatic glucosinolates (GLSs) and on indole metabolites, including camalexin and the growth hormone indole-3-acetic acid. In Broccoli, PfSS101 sulfur assimilation significantly upregulated the relative abundance of several shoot metabolites, in particular, indolic GLSs and phenylpropanoids. These metabolome changes in Broccoli plants coincided with PfSS101-mediated suppression of leaf infections by Xanthomonas campestris. Our study showed the metabolic interconnectedness of plants and their root-associated microbiota.