MicroRNAs (miRNAs) are a class of non-coding RNAs of approximately 21-nt which play important roles in regulating gene expression in plants. Although many miRNA studies have focused on a few model plants, the miRNAs and their target genes remain largely unknown in pepper, one of the most important crops cultivated worldwide. Here we employed high-throughput small RNA sequencing to extensively identify miRNAs in pepper from 10 different libraries, including leaf, stem, root, flower, and six developmental stage fruits. Based on bioinformatics pipeline, we successfully identified 29 and 35 families of conserved and novel miRNAs, respectively. We noticed that some miRNAs, whose targets were validated experimentally in this study, exhibited prominent changes in expression levels during fruit development stages. From the qRT-PCR analysis of the target mRNAs, including the SBP-transcription factor and F-box protein, we found that expression of these two target mRNAs gradually decreased in general during fruit development and was negatively correlated with the expression of their corresponding miRNAs. The validation of miRNA-directed cleavage of these target mRNAs, combined with the results of qRT-PCR analysis, likely suggests that some miRNAs in pepper may play a role in fruit development. Conclusively, our study first utilizes high-throughput sequencing to identify and characterize conserved and novel miRNAs and their targets in pepper, providing a basis for understanding the functional roles of miRNAs in pepper.

The objective of this study was to determine the fatty acid composition of newly developed tissues of germinated soybean seeds. Five soybean accessions with varied fatty acid composition were allowed to germinate in sand under greenhouse conditions. Seedlings were picked up after 4, 6, 8, 10 and 12 days of germination and freeze dried. The fatty acid composition of the newly developed tissues was analyzed by gas chromatography. Significant variation in fatty acid composition was observed between accessions, days of germination, and variety × day of germination in whole and the cotyledons. In the case of newly developed five tissues, significant variation in fatty acid composition were observed between days of germination except oleic acid for root, hypocotyl and epicotyl stem and except stearic acid for hypocotyl and unifoliate leaves while all the parameters were significantly different for accession. Significant interactions of accession and days of germination were observed for palmitic, linoleic and linolenic acid in all tissues; only for oleic acid in hypocotyl, epicotyl and unifoliate leaves; and only for stearic acid in root, hypocotyl, epicotyl and unifoliate leaves. During germination, the fatty acid composition of newly developed tissues changed dramatically but whole seedlings and cotyledons changed slightly. These tissues contained five major fatty acids as found in original seeds, but compositions were totally different from that of the seed: higher in palmitic, stearic and linolenic acid and lower in oleic and linoleic acid. New tissues conserved their fatty acid compositions regardless of genotypic variation in the original seeds.

Oil and fatty acid composition of 648 soybean germplasms of different categories including Korean and American source were analyzed by NIRS (Near Infrared Reflectance Spectrophotometer) method at Yeongnam Agricultural Research Institute, Milyang, Korea. A

Oil and fatty acid compositions of 1,429 germplasms including 1,121 cultivated soybeans for sprout production and 308wild soybeans were analyzed by the NIRS (Near Infrared Reflectance Spectrophotometer) method at Yeongnam AgriculturalResearch Institute, M

In spite water direct seeding cultivation of rice has advantages in terms of laborsaving and cost-down, it demonstrates uneven seedling establishment and difficult weed management. To select an applicable mat for mulching system of water seeded rice, weed occurrence, growth and yield performances of rice, and soil temperature were evaluated in several kinds of biodegradable mulching material. Field studies were conducted at the experimental farm of National Crop Experiment Station in 1999 and 2000. Among the mats tested in 1999, Safer-mat had the greatest effect on inhibiting weed occurrence and Lawn-mat demonstrated the least efficacy of weed control (EWC) value. In Safer-mat treatment, Ludwigia prostrata was the dominant weed species but Echinochloa crus-galli was not observed. Different kinds of mulching material from the mats studied in 1999 were tested in 2000. Biodegradable polyester (PES) coated on the recycled paper for newspaper press (RP) treatments showed similar or higher EWC values than non-mulched broadcast seed rice with 2 times of herbicide application (BC-herbicide) and Safer-mat that was the most effective mat on preventing weed appearance in 1999. Immediately after mat mulching on the surface of paddy soil, five pregerminated rice seeds were manually sown in each 3cm-hole formerly punctured at 30~times 14 cm spacing in 2000. All the 3 kinds of mulching material tested in 2000 had better seedling stand than BC-herbicide treatment. Rice yield in PES coated with 10 thickness on RP (PES10 ~mu~textrmm ＋RP) was a little higher than in BC-herbicide treatment but the former produced less panicles in unit land area than the latter. PES10 ~mu~textrmm ＋RP demonstrated a great effect on raising soil surface temperature than non-mulching treatment throughout the period of seedling establishment.