Yosuke Matsuo

A NMR-based, non-targeted multistep metabolic profiling revealed L-rhamnitol as a metabolite that characterised apples from different geographic origins.

This study utilises (1)H NMR-based metabolic profiling to characterise apples of five cultivars grown either in Japan (Fuji, Orin, and Jonagold) or New Zealand (Fuji, Jazz, and Envy). Principal component analysis (PCA) showed a clear separation between the Fuji-Orin-Jonagold class and the Jazz-Envy class, primarily corresponding to the differences in sugar signals, such as sucrose, glucose, and fructose. Multistep PCA removed the influence of dominant sugars and highlighted minor metabolites such as aspartic acid, 2-methylmalate, and an unidentified compound. These minor metabolites separated the apples into two classes according to different geographical areas. Subsequent partial least squares discriminant analysis (PLS-DA) indicated the importance of the unidentified metabolite. This metabolite was isolated using charcoal chromatography, and was identified as L-rhamnitol by 2D NMR and LC/MS analyses. The remarkable contribution of L-rhamnitol to geographic discrimination suggests that apples may be characterised according to various factors, including storage duration, cultivation method, and climate.

Development of Tilling Robot and Operation Software

A tilling robot was developed to be able to recognize its own position and heading in the field, while performing an unmanned tilling as well as a manual operation. The tilling robot was composed of the robotized vehicle “ROBOTRA” based on a commercial tractor, the navigation system “XNAV” based on a surveying system and the control system composed of a commercial factory computer and an original vehicle controller. The basic operation software for the robot was developed to execute a tilling operation in a conventional manner. Operation software for executing various agricultural works such as seeding and soil paddling were also developed by modifying the basic operation software. By the result of unmanned operation tests, the work efficiency was almost equal to that of conventional manual operation. As to the work accuracy in returning operation, the robot was superior to a skilled operator.

Detection of N-(1-deoxy-d-fructos-1-yl) Fumonisins B2 and B3 in Corn by High-Resolution LC-Orbitrap MS

The existence of glucose conjugates of fumonisin B2 (FB2) and fumonisin B3 (FB3) in corn powder was confirmed for the first time. These “bound-fumonisins” (FB2 and FB3 bound to glucose) were identified as N-(1-deoxy-d-fructos-1-yl) fumonisin B2 (NDfrc-FB2) and N-(1-deoxy-d-fructos-1-yl) fumonisin B3 (NDfrc-FB3) respectively, based on the accurate mass measurements of characteristic ions and fragmentation patterns using high-resolution liquid chromatography-Orbitrap mass spectrometry (LC-Orbitrap MS) analysis. Treatment on NDfrc-FB2 and NDfrc-FB3 with the o-phthalaldehyde (OPA) reagent also supported that d-glucose binding to FB2 and FB3 molecules occurred to their primary amine residues.

Analysis of the Masked Metabolite of Deoxynivalenol and Fusarium Resistance in CIMMYT Wheat Germplasm

Fusarium head blight (FHB) causes significant grain loss and contamination of grains with harmful mycotoxins, especially deoxynivalenol (DON). Fusarium resistance and DON accumulation have been extensively investigated in various cultivars; however, the level of DON-3-O-glucoside (D3G) has not been as carefully studied. In this study, we measured accumulated DON and D3G levels in CIMMYT wheat elite germplasm using an analytical method validated in-house. Co-occurring nivalenol (NIV) and ergostrerol (ERG) were also analyzed. LC-MS/MS and LC-UV analyses were applied to the 50 CIMMYT elite wheat lines. D3G showed rather high correlation with DON (r = 0.82), while FHB symptoms showed slight correlation with DON and D3G (r = 0.36 and 0.32, respectively). D3G/DON ratio varied widely from 8.1 to 37.7%, and the ratio was not related with FHB resistance in this dataset.

Development of an LC-MS/MS Determination Method for T-2 Toxin and Its Glucoside and Acetyl Derivatives for Estimating the Contamination of Total T-2 Toxins in Staple Flours

A determination method previously validated for trichothecenes and zearalenone by means of liquid chromatography-tandem mass spectrometry (LC-MS/MS) was adapted for the quantification of T-2 toxin (T-2) as well as its glucoside and acetyl derivatives, T-2-3-glucoside (T-2-3G) and 3-acetyl-T-2 (3A-T-2). HT-2 toxin (HT-2) and its acetyl derivative 3-acetyl-HT-2 (3A-HT-2) were also included as the target chemicals. Staple flours (56 samples collected from the Singapore market) were examined for contamination from T-2 and/or HT-2 and their derivatives. Among them, 16 flours were found to be contaminated with T-2 and/or HT-2, whereas none was contaminated with T-2-3G and 3A-HT-2, except for trace 3A-T-2 detected in 2 rye samples. Rye flour samples were frequently contaminated with both T-2 and HT-2. Some of the reference materials (RMs) were further analyzed, and T-2-3G and 3A-T-2 were quantitatively detected in corn and wheat RMs. The ratio of T-2-3G to T-2 in the RMs seemed to be much lower than the ratio of deoxynivalenol-3-glucoside to deoxynivalenol usually reported in former studies. To the best of our knowledge, the natural contamination of 3A-T-2 in staple flour is reported here for the first time.

Detection of N-(1-deoxy-D-fructos-1-yl) Fumonisin C1, C2 and C3 in Corn Powder by LC - Orbitrap MS

Detection of N-(1-deoxy-D-fructos-1-yl) fumonisin C1, C2 and C3 (NDfrc-FCs) in a reference material of corn powder were performed with LC-Orbitrap MS. The peaks of NDfrc-FCs were eluted 0.1 ~ 0.3 min earlier than those of fumonisin C1, C2 and C3 (FCs), from the C18 column, probably due to their hydrophilic structures having the carbohydrate residues. At negative ionization mode scan with LC-MS analysis, the fragment ions of the tricarballylic acid (TCA) and characteristic fumonisin ions lacking TCA were detected at the identical retention times with those of respective parent NDfrc-FCs. Mass fragmentation patterns of NDfrc-FCs were confirmed to be almost in consistent with those of FCs. This study is the first report of natural occurrence of NDfrc-FC1, FC2, and FC3 in corn powder.

Robotization of Agricultural Vehicles - Various Operation with Tilling Robot-

Abstract Tilling robot was developed to be able to recognize its own position and heading in the field, while performing an unmanned tilling as well as a manual operation. To improve the ability of the tilling robot, some operation softwares have been studied and developed for executing various agricultural works such as seeding and soil paddling. It was confirmed that unmanned operations with these softwares and the tilling robot could be performed at almost the same accuracy and efficiency as manual operations.