Young-Sang Lee

Functional analyses of individual mating-type transcripts at MAT loci in Fusarium graminearum and Fusarium asiaticum.

Members of the Fusarium graminearum species (Fg) complex, which are homothallic ascomycetous species, carry two opposite mating-type (MAT) loci in a single nucleus for controlling sexual development. We investigated the roles of three (MAT1-1-1, MAT1-1-2, and MAT1-1-3) and two (MAT1-2-1 and MAT1-2-3) transcripts located at both loci in representative Fg complex species (F. graminearum and Fusarium asiaticum). In self-fertile F. graminearum strains, the transcript levels of MAT1-1-1, MAT1-2-1, and MAT1-2-3 peaked 2 days after sexual induction (dai) and then remained high until 12 dai, whereas MAT1-1-2 and MAT1-1-3 transcripts reached peak levels between 4 and 8 dai. In contrast, all of the MAT transcripts in self-sterile F. asiaticum strains accumulated at much lower levels than those in F. graminearum during the entire time. Targeted gene deletions confirmed that MAT1-1-1, MAT1-1-2, MAT1-1-3, and MAT1-2-1 were essential for self-fertility in F. graminearum, but MAT1-2-3 was not. All MAT-deleted strains (except ΔMAT1-2-3) produced recombinant perithecia when outcrossed to a self-fertile strain. These results indicate that developmental up-regulation of the individual MAT genes in both a proper fashion and quantity is critical for sexual development, and that alterations in the gene expression could be attributed to the variation in self-sterility among the Fg complex.

Isoflavones profiling of soybean [Glycine max (L.) Merrill] germplasms and their correlations with metabolic pathways

The isoflavone diversity (44 varieties) of the soybean, Glycine max (L.) Merrill, from China, Japan, and Korea was examined by high-performance liquid chromatography. The profiles of 12 isoflavones identified from the grains were subjected to data-mining processes, including partial least-squares discriminant analysis (PLS-DA), Pearsons correlation analysis, and hierarchical clustering analysis (HCA). Although PLS-DA did not reveal significant differences among extracts of soybean from 3 countries, the results clearly show that the variation between varieties was low. The CS02554 variety was separate from the others in the first 2 principal components of PLS-DA. HCA of these phytochemicals resulted in clusters derived from closely related biochemical pathways. Daidzin, genistin, and glycitin contents were significantly correlated with their respective malonyl glycoside contents. Daidzein content correlated positively with genistein content (r=0.8189, P<0.0001). The CS02554 variety appears to be a good candidate for future breeding programs, as it contains high levels of isoflavone compounds. These results demonstrate the use of metabolite profiling combined with chemometrics as a tool for assessing the quality of food and identifying metabolic links in biological systems.

Comparisons of nutritional and phytochemical property of genetically modified CMV-resistant red pepper and its parental cultivar

The aim of this study was to compare the nutritional composition of a genetically modified (GM) CMV-resistant red pepper strain with its parental line. Specifically, the nutrient content (moisture, protein, lipid, ash, carbohydrate, and energy), minerals, fatty acid composition, capsaicinoids (capsaicin and dihydrocapsaicin), free sugars (glucose, sucrose, and fructose), vitamin E isomers (α-, β-, γ-, and δ-tocopherols), vitamin C, phytosterols (campesterol, stigmasterol, and β-sitosterol), squalene contents, and ASTA values were analyzed and compared. Most of the analyzed compounds showed no significant differences between the GM red peppers and the parental line. The only significant difference was observed in stigmasterol content, but the difference was below the 15% natural-fluctuation threshold. These results suggest that the CMV-GM pepper is equivalent to its parental line in terms of nutritional and phytochemical composition.

Sialolithiasis in a stump of Wharton's duct of an aplastic unilateral submandibular gland

Congenital absence of the salivary glands is an uncommon disorder. Isolated aplasia of a unilateral submandibular gland is rare and only 6 cases have been reported. The formation of a sialolith within the remaining Whartons duct, associated with isolated aplasia of a unilateral submandibular gland, has not been reported previously. The authors report two cases of sialolithiasis within the ipsilateral remaining Whartons duct in patients with isolated aplasia of a unilateral submandibular gland.

Human endometrial cell coculture reduces the endocrine disruptor toxicity on mouse embryo development

BackgroundsPrevious studies suggested that endocrine disruptors (ED) are toxic on preimplantation embryos and inhibit development of embryos in vitro culture. However, information about the toxicity of endocrine disruptors on preimplantation development of embryo in human reproductive environment is lacking.MethodsBisphenol A (BPA) and Aroclor 1254 (polychlorinated biphenyls) were used as endocrine disruptors in this study. Mouse 2-cell embryos were cultured in medium alone or vehicle or co-cultured with human endometrial epithelial layers in increasing ED concentrations.ResultsAt 72 hours the percentage of normal blastocyst were decreased by ED in a dose-dependent manner while the co-culture system significantly enhanced the rate and reduced the toxicity of endocrine disruptors on the embryonic development in vitro.ConclusionsIn conclusion, although EDs have the toxic effect on embryo development, the co-culture with human endometrial cell reduced the preimplantation embryo from it thereby making human reproductive environment protective to preimplantation embryo from the toxicity of endocrine disruptors.

Resequencing Reveals Different Domestication Rate for BADH1 and BADH2 in Rice (Oryza sativa)

BADH1 and BADH2 are two homologous genes, encoding betaine aldehyde dehydrogenase in rice. In the present study, we scanned BADHs sequences of 295 rice cultivars, and 10 wild rice accessions to determine the polymorphisms, gene functions and domestication of these two genes. A total of 16 alleles for BADH1 and 10 alleles for BADH2 were detected in transcribed region of cultivars and wild species. Association study showed that BADH1 has significant correlation with salt tolerance in rice during germination stage, the SNP (T/A) in exon 4 is highly correlated with salt tolerance index (STI) (P<10−4). While, BADH2 was only responsible for rice fragrance, of which two BADH2 alleles (8 bp deletion in exon 7 and C/T SNP in exon 13) explain 97% of aroma variation in our germplasm. Theses indicate that there are no overlapping functions between the two homologous genes. In addition, a large LD block was detected in BADH2 region, however, there was no large LD blocks in a 4-Mb region of BADH1. We found that BADH2 region only showed significant bias in Tajima’s D value from the balance. Extended haplotype homozygosity study revealed fragrant accessions had a large LD block that extended around the mutation site (8 bp deletion in exon 7) of BADH2, while both of the BADH1 alleles (T/A in exon 4) did not show large extended LD block. All these results suggested that BADH2 was domesticated during rice evolution, while BADH1 was not selected by human beings.

Evaluation of phytonutrients in Adlay (Coix lacryma- jobi L.) seeds

respectively. Of the six detected fatty acids, the major fatty acids were oleic (46.3%) and linoleic acids (37.4%). Seed squalene content exhibited high correlationship with phytosterols, but not with tocopherols. Among the tested varieties, variety Yulmu 1 showed a relatively higher proportion of phytonutrients, suggesting its potential as a gene source for further breeding.

Variations in proximate nutrients, phytochemicals, and antioxidant activity of field-cultivated red pepper fruits at different harvest times

Red pepper (Capsicum annuum L.), an important horticultural crop, is typically harvested several times within one season. The goal of this study was to elucidate the harvest time-dependent variation and accumulation patterns of phytochemicals and any aßsociated antioxidant activity in red pepper. Fully matured red pepper fruits, grown in an open field, were harvested six times during the season. They were evaluated for their proximate nutrient contents, as well as their minerals, vitamins, capsaicinoids, total flavonoid, total phenols, squalene, phytosterols, and fatty acids, and for antioxidant activity. The content of most phytochemicals varied significantly at different times of harvest. Phytochemicals such as capsaicinoids, vitamin C, total phenols, total flavonoid, ß-carotene, and calcium, as well as antioxidant activity, had higher values in the initial and final harvests, while P, K, and Na decreased continuously with the progression of the harvest season. Squalene content increased continuously, while vitamin E and phytosterol contents were relatively stable throughout the harvest season. Different phytonutrients exhibited different levels of harvesting time-dependent variation; capsaicinoid had the highest coefficient of variation (CV, 55.44%), followed by squalene (40.51%), total flavonoids (15.97%), and vitamin C (10.57%). Total vitamin E, phytosterols, fatty acids, and the proximate nutrients were relatively constant, with low CVs (<10.0%). Among the phytonutrients, total flavonoids (r = 0.841), vitamin C (r = 0.801), ß-carotene (r = 0.738), and total phenol (r = 0.705) were highly positively correlated with antioxidant activity throughout the harvesting season. These results suggest that the content of phytochemicals, and their associated health benefits, may be affected by red pepper harvest time throughout the harvest season.

Natural variations in OsγTMT contribute to diversity of the α-tocopherol content in rice

Tocopherols and tocotrienols, collectively known as tocochromanols, are lipid-soluble molecules that belong to the group of vitamin E compounds. Among them, α-tocopherol (αΤ) is one of the antioxidants with diverse functions and benefits for humans and animals. Thus, understanding the genetic basis of these traits would be valuable to improve nutritional quality by breeding in rice. Genome-wide association study (GWAS) has emerged as a powerful strategy for identifying genes or quantitative trait loci (QTL) underlying complex traits in plants. To discover the genes or QTLs underlying the naturally occurring variations of αΤ content in rice, we performed GWAS using 1.44 million high-quality single-nucleotide polymorphisms acquired from re-sequencing of 137 accessions from a diverse rice core collection. Thirteen candidate genes were found across 2-year phenotypic data, among which gamma-tocopherol methyltransferase (OsγTMT) was identified as the major factor responsible for the αΤ content among rice accessions. Nucleotide variations in the coding region of OsγTMT were significantly associated with the αΤ content variations, while nucleotide polymorphisms in the promoter region of OsγTMT also could partly demonstrate the correlation with αΤ content variations, according to our RNA expression analyses. This study provides useful information for genetic factors underlying αΤ content variations in rice, which will significantly contribute the research on αΤ biosynthesis mechanisms and αΤ improvement of rice.

Short-term effects of Al3+ on the osmotic behavior of red beet (Beta vulgaris L.) protoplasts

The short-term (less than 10 min) effects of Al3+ on the biophysical properties of plasma membranes were investigated by time-series image analysis of osmotically-induced volumetric and morphologic changes of red beet (Beta vulgaris L.) protoplasts. Exposure to Al3+ under hypotonic conditions reduced the volumetric expansion of protoplasts and their resultant burst: i.e. lysis of protoplasts in a concentration-dependent manner. Under hypertonic conditions, protoplasts exposed to Al3+ underwent an enhanced volumetric contraction in cross-sectional area, while maintaining higher protoplast roundness. The residual effects of Al3+ pre-treatment on subsequent osmotic behavior were also examined, and protoplasts pre-treated with Al3+ also exhibited less lysis during subsequent exposure to hypotonic conditions and enhanced volumetric contractions and higher roundness under subsequent hypertonic conditions. Under our experimental conditions, Al3+ consistently minimized protoplast surface area by inhibiting osmotic expansion or by enhancing osmotic contraction, as well as by maintaining higher protoplast roundness. These results suggested that the electrostatic property of Al3+ might have induced the binding and possible cross-linking of negatively-charged sites on the plasma membrane surface. This may be an important factor in understanding the mechanism of Al3+ phytotoxicity.