Novel glucosinolate composition lacking 4-methylthio-3-butenyl glucosinolate in Japanese white radish (Raphanus sativus L.)

Dynamic profiling of intact glucosinolates in radish by combining UHPLC-HRMS/MS and UHPLC-QqQ-MS/MS

Glucosinolates (GSLs) and their degradation products in radish confer plant defense, promote human health, and generate pungent flavor. However, the intact GSLs in radish have not been investigated comprehensively yet. Here, an accurate qualitative and quantitative analyses of 15 intact GSLs from radish, including four major GSLs of glucoraphasatin (GRH), glucoerucin (GER), glucoraphenin (GRE), and 4-methoxyglucobrassicin (4MGBS), were conducted using UHPLC-HRMS/MS in combination with UHPLC-QqQ-MS/MS. Simultaneously, three isomers of hexyl GSL, 3-methylpentyl GSL, and 4-methylpentyl GSL were identified in radish. The highest content of GSLs was up to 232.46 μmol/g DW at the 42 DAG stage in the 'SQY' taproot, with an approximately 184.49-fold increase compared to the lowest content in another sample. That the GSLs content in the taproots of two radishes fluctuated in a similar pattern throughout the five vegetative growth stages according to the metabolic profiling, whereas the GSLs content in the '55' leaf steadily decreased over the same period. Additionally, the proposed biosynthetic pathways of radish-specific GSLs were elucidated in this study. Our findings will provide an abundance of qualitative and quantitative data on intact GSLs, as well as a method for detecting GSLs, thus providing direction for the scientific progress and practical utilization of GSLs in radish.

Large insertion in radish GRS1 enhances glucoraphanin content in intergeneric hybrids, Raphanobrassica (Raphanus sativus L. x Brassica oleracea var. acephala)

Glucosinolates (GSLs), precursors of isothiocyanates (ITCs), are present in Brassicaceae plants have been found to have health benefits. Sulforaphane (4-(methylsulfinyl)butyl ITC) is an ITC stored in the form of 4-(methylsulfinyl)butyl GSL (glucoraphanin, 4MSOB) in Brassica vegetables, such as broccoli and kale. Sulforaphane activates Nrf2 expression, a transcription factor responsible for inducing physiological activities such as detoxification in the human body, and it represents a functional component unique to cruciferous vegetables. Raphanobrassica is an inter-generic hybrid between radish and kale, and it contains a high amount of 4MSOB. However, Raphanobrassica contains as much 4-methylsulfinyl-3-butenyl GSL (glucoraphenin, 4MSO3B) as it does 4MSOB. GLUCORAPHASATIN SYNTHASE 1 (GRS1) is an enzyme present in radish that synthesizes 4-methylthio-3-butenyl GSL (glucoraphasatin, 4MT3B), a precursor of 4MSO3B, using 4-(methylthio)butyl GSL (glucoerucin, 4MTB) as a substrate. Since the precursor of 4MSOB is also 4MTB, it was considered that both 4MSOB and 4MSO3B accumulate owing to competition in Raphanobrassica. We hypothesized that owing to the impaired function of GRS1 in Raphanobrassica, it may be possible to breed Raphanobrassica cultivars containing a high 4MSOB content. In this study, we generated Raphanobrassica populations with functional and defective GRS1 and compared the GSL composition in the two populations using high-performance liquid chromatography. The mean 4MSOB content in leaves of the defective-type populations was higher than that in the functional-type population, and the defective/functional ratio ranged from 2.02 to 2.51-fold, supporting this hypothesis. Furthermore, leaves, flower buds, stems, and roots contained higher amounts of 4MSOB in the defective population than in the functional population. The leaf 4MSOB content of defective Raphanobrassica grown in this study was comparable to that of previously studied vegetables (such as broccoli sprouts) with high 4MSOB content. Raphanobrassica with defective GRS1 represents a new leafy vegetable with high 4MSOB content which exhibits anti-cancerous and anti-inflammatory potentials.

Physiological and biochemical markers of gamma irradiated white radish (Raphanus sativus)

PURPOSE

A field experiment was performed to investigate the impact of low-dose gamma rays on growth parameters and bioactive compounds of white radish.

MATERIALS AND METHODS

White radish seeds were irradiated by gamma rays dose levels (10, 20, 40 and 80 Gy) beside control. Physiological and biochemical markers were done to follow the effect of gamma rays on white radish.

RESULTS

The results revealed that gamma rays increased growth parameters with increasing irradiation to a dose of 40 Gy. The maximum increments were found at 14.64 (cm), 48.30 (cm), 20.84 (cm) and 5.51 (cm) for leaves number, leaves length, roots length and roots diameter, respectively, with a dose of 40 Gy. By increasing the irradiation dose to 80 Gy, the results showed reduction in all parameters studied. Ascorbic acid gave the maximum increase with the dose of 40 Gy, while phenols, flavonoids, antioxidant activity, peroxidase, and polyphenol oxidase showed the highest increase with the dose 80 of Gy in radish leaves. Similar trend was observed for the radish roots. Furthermore, the protein and isoenzyme profiles of peroxidase and polyphenol oxidase changed and induced alteration by different irradiation dose levels.

CONCLUSION

Gamma rays can be a useful tool for increasing the growth and biochemical content of white radish plants and perhaps other food crops.

Benzoic Acid, Chlorine Dioxide, and 1-Methylcyclopropene Induce Flavonoid Metabolic Shifts in Postharvest Flowering Chinese Cabbage Revealed by High-Dimensional Analytical Data

Flowering Chinese cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee) is one of the most popular vegetables in China. However, the loss of the functional ingredients in postharvest flowering Chinese cabbage during storage is still serious, owing to the unclear causes of the metabolic shifts. Herein, benzoic acid, chlorine dioxide, and 1-methylcyclopropene (1-MCP) could maintain the quality of postharvest flowering Chinese cabbage, and 1-MCP showed the best effect. Furthermore, transcript-metabolite profiling of the treatments revealed a transcript-metabolite correlation network of the flavonoid biosynthesis pathways with a range of 3 to 3662 differentially expressed genes (DEGs) and a range of 23 to 37 differentially accumulated metabolites (DAMs). Surprisingly, 1-MCP had the best effect on shelf life among the treatments, although chlorine dioxide could stimulate the expression of four critical differential genes (Bra007142, Bra008792, Bra009358, and Bra027457) involved in delaying flavonoid degradation (hesperetin, chalcone, rutin, baicalein). As a result, our findings will help to improve our understanding of the regulation of flavonoid production in relation to the quality of postharvest flowering Chinese cabbage during storage.

Glucosinolate Profiles in Different Organs of 111 Radish Accessions and Candidate Genes Involved in Converting Glucobrassicin to 4-Hydroxyglucobrassicin

Glucosinolate (GSL) not only has highly physiological function for plants but also has considerable human interest. We analyzed the GSL compositions and levels in four organs of 111 radish accessions. Seven major GSLs were detected (approximately 5-245 μmol g^-1 DW), among which 4-(methylsulfinyl)but-3-enyl GSL and 4-methylsulfanyl-3-butenyl GSL were the dominant GSLs. GSL levels varied substantially among species and groups, and some genotypes/groups with special GSL profiles were identified. The total GSL level was higher in seeds than in sprouts, taproots, and leaves. Additionally, a correlation analysis revealed that seed 4-(methylsulfinyl)but-3-enyl GSL levels were highly correlated with sprout GSL levels. Moreover, a candidate gene (RsCYP81F2.3) encoding an enzyme that catalyzes the conversion of indol-3-ylmethyl GSL to 4-hydroxyindol-3-ylmethyl GSL was identified based on the detection and analysis of three radish accessions with relatively high indol-3-ylmethyl GSL, low 4-hydroxyindol-3-ylmethyl GSL, and 4-methoxyindol-3-ylmethyl GSL levels in their seeds. Our results provide some insights for finding materials and genes relevant for breeding new varieties with ideal GSL compositions and levels.

Transcriptome analysis of melatonin regulating the transformation of glucoraphanin to sulforaphane in broccoli hairy roots

Sulforaphane (SF) is one of the most effective natural products in preventing and fighting cancer, found in cruciferous plants. In this study, broccoli hairy roots grown for 20 d were used as the experimental material, and it was treated with 500 μmol/L melatonin (MT) for 0, 12 and 32 h to explore the effect of MT on the conversion of glucoraphanin (GRA) to SF. Results showed that the yields of GRA and SF were the largest under MT treatment for 12 h, which were 1.53 and 1.93-fold, respectively, compared to 0 h. However, Myrosinases activity was the highest under MT treatment for 32 h, which was 1.42-fold compared to that of the 0 h. The differential expression of key genes involved in GRA conversion to SF in broccoli hairy roots was identified transcriptome sequencing, and the path of the transformation from GRA to SF was simulated, which provided a theoretical basis for establishing an efficient transformation system from GRA to SF.

Identification of genome-wide single-nucleotide polymorphisms among geographically diverse radish accessions

Radish (Raphanus sativus L.) is cultivated around the world as a vegetable crop and exhibits diverse morphological and physiological features. DNA polymorphisms are responsible for differences in traits among cultivars. In this study, we determined genome-wide single-nucleotide polymorphisms (SNPs) among geographically diverse radish accessions using the double-digest restriction site-associated DNA sequencing (ddRAD-Seq) method. A total of 52,559 SNPs was identified in a collection of over 500 radish accessions (cultivated and wild) from East Asia, South and Southeast Asia, and the Occident and Near East. In addition, 2,624 SNP sites without missing data (referred to as common SNP sites) were identified among 510 accessions. Genetic diversity analyses, based on the common SNP sites, divided the cultivated radish accessions into four main groups, each derived from four geographical areas (Japan, East Asia, South and Southeast Asia, and the Occident and Near East). Furthermore, we discuss the origin of cultivated radish and its migration from the West to East Asia. SNP data generated in this work will facilitate further genetic studies on the radish breeding and production of DNA markers.

Analysis of Overturning and Vibration during Field Operation of a Tractor-Mounted 4-Row Radish Collector toward Ensuring User Safety

The overturning stability and vibration of upland crop machinery under development are important issues for analysis because farms for upland crops are usually uneven, which may cause work-related fatalities, and vibration affects user comfort and reduces the durability of components. In this study, the overturning stability and vibration of a tractor-mounted radish collector were investigated to ensure safety during radish collection. To analyze lateral stability, the center of gravity (CG) of the tractor-mounted radish collector system was calculated mathematically. Then, a simulation was performed to determine the lateral overturning angles at different folding positions of the radish conveyor belt and load conditions, and the results were validated through tests. Vibration sensors were used to measure the vibration levels and the power spectrum density (PSD) was obtained to check the cyclic apparatuses of the major frequencies. The load conditions, different conveyor speeds, and locations were considered as factors affecting the vibration levels. Considering the physical parameters of the tractor–collector system, the analytical overturning angle was 30.5°. The average overturning angle difference between the simulation and validation was 5°, and the difference between loaded and unloaded conditions was 2°. For 0, 45, and 90° folding positions of the conveyor belt, overturning angles increased and varied from 0.5 to 1°. The vibration level was greater under the unloaded conditions and increased with an increase in the conveyor speed. Vibrations under the loaded condition (0.37~0.48 ms−2) satisfied the ISO (International Organization for Standardization) standard (except the first conveyor belt). According to the PSD analysis, high magnitude peaks (>25 dB) appeared frequently in all directions, which indicates a high possibility of damage to the first conveyor belt. This study provides useful information for improving the safety and durability of agricultural machinery for uneven and sloped field conditions.

The combined effects of ultrasound and lactic acid in inactivating microorganisms on fresh radish (Raphanus raphanistrum subsp. sativus): Microbiological and quality changes

In order to reduce the risk of microbial contamination in fresh radish (Raphanus raphanistrum) and ensure its safety, combined effects of ultrasound and lactic acid in inactivating microorganisms and quality changes of radish were studied. Fresh radish samples were inoculated with Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and Shigella sonnei separately and were treated with lactic acid (L) 1% and 2%, ultrasound (U) with the amplitude of 0%, 25%, 50%, and 75% for 15 and 30 min and their combination. The quality parameters, including total phenol content, firmness, and total color change, were evaluated on the day of the experiment and after 24 hr of cold storage. Results showed that both applied treatments and their combinations had significant (p < .05) inhibitory effect on all of the studied bacteria. Total phenolic content of the ultrasound treated samples led to higher amounts comparing to other samples. Results showed that using ultrasound power (75%), for 30 min significantly (p < .05) decreased the firmness of samples after 24 hr of cold storage. In conclusion, the application of ultrasound and lactic acid can extend the shelf life of fresh radish.

Differential expression of major genes involved in the biosynthesis of aliphatic glucosinolates in intergeneric Baemoochae (Brassicaceae) and its parents during development

Thus study found the temporal and spatial relationship between production of aliphatic glucosinolate compounds and the expression profile of glucosinolate-related genes during growth and development in radish, Chinese cabbage, and their intergeneric hybrid baemoochae plants. Glucosinolates (GSLs) are one of major bioactive compounds in Brassicaceae plants. GSLs play a role in defense against microbes as well as chemo-preventative activity against cancer, which draw attentions from plant scientists. We investigated the temporal relationship between production of aliphatic Glucosinolate (GSLs) compounds and the expression profile of GSL related genes during growth and development in radish, Chinese cabbage, and their intergeneric hybrid, baemoochae. Over the complete life cycle, Glucoraphasatin (GRH) and glucoraphanin (GRE) predominated in radish, whereas gluconapin (GNP), glucobrassicanapin (GBN), and glucoraphanin (GRA) abounded in Chinese cabbage. Baemoochae contained intermediate levels of all GSLs studied, indicating inheritance from both radish and Chinese cabbage. Expression patterns of BCAT4, CYP79F1, CYP83A1, UGT74B1, GRS1, FMOgs-ox1, and AOP2 genes showed a correlation to their corresponding encoded proteins in radish, Chinese cabbage, and baemoochae. Interestingly, there is a sharp change in gene expression pattern involved in side chain modification, particularly GRS1, FMOgs-ox1, and AOP2, among these plants during the vegetative and reproductive stage. For instance, the GRS1 was strongly expressed during leaf development, while both of FMOgs-ox1 and AOP2 was manifested high in floral tissues. Furthermore, expression of GRS1 gene which is responsible for GRH production was predominantly expressed in leaf tissues of radish and baemoochae, whereas it was only slightly detected in Chinese cabbage root tissue, explaining why radish has an abundance of GRH compared to other Brassica plants. Altogether, our comprehensive and comparative data proved that aliphatic GSLs biosynthesis is dynamically and precisely regulated in a tissue- and development-dependent manner in Brassicaceae family members.

Radish (Raphanus sativus) and Diabetes

For more than three decades, various in vitro and in vivo studies have linked radishes with diabetes, though this link has not been discussed. This review systematically addresses and summarizes the effect of radishes on diabetes. We searched the Web of Science, PubMed, and EMBASE databases for English language articles from June 1987 through May 2017 using the key words "radish" and "diabetes," and the references from particular reports were also considered if relevant. In summary, radish has been identified as having antidiabetic effects, making it favorable for those with diabetic conditions. This may be due to its ability to enhance the antioxidant defense mechanism and reduce the accumulation of free radicals, affect hormonal-induced glucose hemostasis, promote glucose uptake and energy metabolism, and reduce glucose absorption in the intestine. However, this summary requires further confirmation in research in vivo studies and clinical trials.