Potato tuber metabolomics-based prediction of chip color quality and application using gas chromatography/flame ionization detector.

Potato (Solanum tuberosum L.) tubers are usually harvested once a year; thus, long-term storage is required to supply quality-assured tubers throughout the year. Further, an applicable method to predict tuber quality during storage is needed. In this study, gas chromatography-mass spectrometry (GC/MS) metabolomics was applied to identify applicable biomarkers for prediction of potato chip color based on 3 years' field-grown tubers. The projections to latent structures (PLS) prediction model, calculated from a metabolome data set obtained before storage, was consistent with actual measured chip color values. Additionally, GC with frame ionization detector (GC/FID) metabolite fingerprinting simultaneously re-constructed more reliable and relevant prediction models for chip color quality compared to GC/MS. Moreover, nine metabolites detected by GC/MS analysis were further validated as applicable prediction markers. This strategy will provide a practical and cost-effective quality-control tool for potato processing manufacturers on an industrial scale.

Comparison of gene expression profiles and responses to zinc chloride among inter- and intraspecific hybrids with growth abnormalities in wheat and its relatives.

Hybrid necrosis is a well-known reproductive isolation mechanism in plant species, and an autoimmune response is generally considered to trigger hybrid necrosis through epistatic interaction between disease resistance-related genes in hybrids. In common wheat, the complementary Ne1 and Ne2 genes control hybrid necrosis, defined as type I necrosis. Two other types of hybrid necrosis (type II and type III) have been observed in interspecific hybrids between tetraploid wheat and Aegilops tauschii. Another type of hybrid necrosis, defined here as type IV necrosis, has been reported in F1 hybrids between Triticum urartu and some accessions of Triticum monococcum ssp. aegilopoides. In types I, III and IV, cell death occurs gradually starting in older tissues, whereas type II necrosis symptoms occur only under low temperature. To compare comprehensive gene expression patterns of hybrids showing growth abnormalities, transcriptome analysis of type I and type IV necrosis was performed using a wheat 38k oligo-DNA microarray. Defense-related genes including many WRKY transcription factor genes were dramatically up-regulated in plants showing type I and type IV necrosis, similarly to other known hybrid abnormalities, suggesting an association with an autoimmune response. Reactive oxygen species generation and necrotic cell death were effectively inhibited by ZnCl2 treatment in types I, III and IV necrosis, suggesting a significant association of Ca(2+) influx in upstream signaling of necrotic cell death in wheat hybrid necrosis.

Gas chromatography-mass spectrometry metabolomics-based prediction of potato tuber sprouting during long-term storage.

In order to supply potato (Solanum tuberosum L.) tubers for the processed food industry throughout the year, suppliers should provide consistent quality potatoes even after long-term storage. Despite being one of the most important foods, there is no simple way to control tuber quality and, in particular, controlling sprouting. Chemical suppression such as chlorpropham is used to inhibit sprouting, however, the regulatory status of such chemical inhibition differs in each country. Gas chromatography-mass spectrometry-based metabolomics was applied to identify the applicable biomarkers for prediction of potato sprouting during long-term storage. Sprouting was measured in chipping potatoes, and these were also subjected to metabolite profiling to develop a predictive model. The model was based on projections to latent structures (PLS) regression calculated from a metabolome data set obtained before storage and was consistent with actual measured sprouting values. Sucrose, phosphate, and amino acids were selected as valid contributing biomarkers for prediction in a validation field experiment. These biomarkers will contribute to the development of a successful novel method for prediction and control of potato tuber quality during long-term storage.