UDP-glucose 4-epimerase catalyzes the reversible conversion of UDP-glucose to UDP-galactose. The gene, named BrUGE1, isolated from a Chinese cabbage composes of a total length of 1,328 bp that contains a single open reading frame (ORF) of 1,056 bp which encodes a polypeptide of 351 amino acid residues with a calculated mass of 39.0 kDa. Expression analysis showed that BrUGE1 is tissue specific and highly expressed in stem of rice plant. Interestingly, BrUGE1 mRNA was highly accumulated by drought stress with significantly higher amount of soluble sugar. Morphological evaluation showed an increase in yield and yield components compared to the wild type. Moreover, a better growth performance on galactose as well as higher UGE1 expression was observed in transgenic rice lines than in wild type. In the Ubi-1::BrUGE1 lines, the increase of UGE1 expression was apparently sufficient to overcome the toxic effects of galactose. Taken together, the Ubi-1::BrGUE1 rice lines increased yield probably by increasing the rate of filled grains. The enhanced drought tolerance may be due to the induction of soluble sugar which may act as osmolyte to compensate dehydration during drought stress.

Rice is one of the most important major food crops which provide the major food for more than half of global population. To improve the grain quality as well as grain yield has been the essential breeding goal in rice. The composition of amylopectin is the determinant of rice eating quality under certain threshold of protein content and the ratio of amylose and amylopectin. In this study, RBE 1 driven by CaMV-35S promoter was constructed and transformed using Agrobacterium tumefaciens. We selected single copy with low amylose content among transgenic lines. The mRNA expression was investigated using RT-PCR, and enzyme activity was determined using activity staining method in mid-milky stage endosperm. Also, the overexpression vectors for RBE 1 and SSS 1 driven by seed specific globulin promoter were constructed, respectively. Moreover, the RNA interference vectors for soluble starch synthase 1 and granule bound starch synthase 1 derived by CaMV35S promoter were constructed, respectively and transformed using Agrobacterium tumefaciens. The transgene has been confirmed by amplification of HPT and target gene. The transgenic plants obtained will be used to investigate the gene function of related starch pathway in plant cells using Gopumbyeo as a wild type rice, based on the gain-of-function and the loss-of-function. The development of designed site-specific endonucleases boosted the establishment of gene targeting (GT) techniques in a row of different species. However, the methods described in plants require a highly efficient transformation and regeneration procedure and, therefore, can be applied to very few species. Here, we describe a highly efficient GT system that is suitable for all transformable plants regardless of transformation efficiency. Efficient in planta GT was achieved in rice by expression of a site specific endonuclease (SSS1::ZFN) that not only cuts within the target but also the chromosomal transgenic donor, leading to an excised targeting vector.

A cDNA clone encoding CBL-interacting protein kinase 1 (CIPK1) was isolated from Chinese cabbage seedlings. The gene, BrCIPK1 consisted of 1,982 bp long with 216 bp of the 5’-untranslated region (UTR), 1,509 bp of the coding region and 257 bp of the 3’-UTR. It is highly conserved CBL-interacting module with absolutely conserved domain among the 15 amino acid NAF domain of the 15 related genes. Southern blot analysis showed a single copy number. BrCIPK1 gene was localized in the cytoplasm and peripheral region in the plant cell which is highly expressed in seedling of rice and in the shoot and pistil of Arabidopsis. Analyses of gene expression on Ubi-1::BrCIPK1 rice lines was differentially accumulated by cold, salinity and drought, indicating its biological roles in the multiple stress response pathways in plants. Further, the expression of BrCIPK1 is hijacked by rice calcineurin-B-like protein (OsCBL5). Moreover, mRNA expression of P5CS1, a gene responsible for proline biosynthesis is regulated by the BrCIPK1 during abiotic stresses resulting to improved accumulation of proline. The interaction of BrCIPK1 with OsCBL5 along with the regulation of P5CS1 explained the enhanced tolerance of transgenic rice. This gene could be used in the development of rice varieties with enhanced tolerance to abiotic stresses.

MYB-like domain (MLD) gene is a transcription factor that plays a diverse role in plant development and in response to abiotic stresses. In this study, we isolated and developed CaMV35S::OsMLD rice lines and determined its expression pattern under abiotic stresses. It has Myb_CC_LHEQLE superfamily similar to most transcription factor genes but with a very unique binding domain of SHLQKYR in the C-terminal region. Overexpressing rice lines showed enhanced tolerance to salinity with elevated mRNA transcript. Additionally, mRNA transcripts were up-regulated by ABA, H2O2 and dehydration stresses. Further investigation in the enhanced tolerance to salinity showed an increased accumulation of proline and a decreased in malondialdehyde contents indicating that OsMLD gene may be involved in the regulation of proline and osmolytes during abiotic stresses. These results showed that OsMLD gene could be used in the development of rice intended for soil with salinity-related problem.

UDP-glucose 4-epimerase (UGE) catalyzes the reversible conversion of UDP-glucose to UDP-galactose. The gene, named BrUGE1, isolated from a Chinese cabbage had a total length of 1,328 bp that contains a single open reading frame (ORF) of 1,056 bp which encodes a polypeptide of 351 amino acid residues with a calculated mass of 39.0 kDa. Sequence analysis of BrUGE1 protein has the characteristic of an active site tetrad and NAD-binding motif (typically TGXXGXXG) of the extended short chain dehydrogenase/ reductase (SRD) superfamily. Expression analysis showed that BrUGE1 is tissue specific and highly expressed in stem of rice plant. Interestingly, BrUGE1 mRNA was highly accumulated by drought stress with significantly higher amount of soluble sugar. Morphological evaluation showed an increase in yield by 27%. Panicle length, number of productive tillers/hill, and filled spikelets were significantly increased by 17~20% compared to the wild type Gopum. Moreover, the growth of the wild type Gopum seedlings on galactose was increasingly inhibited with a decrease in UDP-glc epimerase 1 expression compared to the transgenic rice lines. In the Ubi-1::BrUGE1 lines, the increase of UDP-glc epimerase 1 expression was apparently sufficient to overcome the toxic effects of galactose. Taken together, the Ubi-1::BrGUE1 rice lines increased yield probably by increasing the rate of filled grains. The enhanced drought tolerance may be due to the induction of soluble sugar which may act as osmolyte to compensate dehydration during drought stress.

The latest report on draft genome of Brassica rapa sequence has been published. To elucidate the functions of a large population of these genes and to search efficiently for agriculturally useful genes, the Full-length cDNA Over-eXpressor (FOX) gene hunting system was used. The FOX library was transformed into rice by Agrobacteriummediated transformation. Approximately 1,150 FOX-rice lines were generated. Genomic PCR analysis indicated that the average length of FL-cDNAs was 900∼1,200 bp with functional annotation of many unknown function (35.5%). Most of the randomly selected transgenic rice lines showed overexpression (92%) and barely mRNA expression in the wild type Gopum. Moreover, 94% of the 850 transgenic rice lines were moderately tolerant (slightly yellow) to cold and 9 lines were tolerant (seedling light green). For the salinity evaluation, most of the transgenic lines (85%) were highly susceptible whereas seven lines were tolerant. In addition, morphological evaluation of rice lines showed minimal phenotypic alteration (12%). About 25.1 and 22% were earlier in terms of days to heading and chlorophyll contents, respectively. Further, 18% of FOX rice lines showed lower chlorophyll contents. Filled grains, number of tillers, panicle length, culm and plant height were relatively less variable among the lines. These results provided useful genes for functional analyses in the mechanisms of identified transgenic tolerant lines.

A cDNA clone encoding CBL-interacting protein kinase 1 (CIPK1) was isolated from Chinese cabbage seedlings. The gene, BrCIPK1 consisted of 1,982 bp long with 216 bp of the 5’-untranslated region (UTR), 1,509 bp of the coding region and 257 bp of the 3’-UTR. It is highly conserved CBL-interacting module with absolutely conserved domain among the 15 amino acid NAF domain of the 15 related genes. Southern blot analysis showed a single copy number. BrCIPK1 gene was localized in the cytoplasm and peripheral region in the plant cell which is highly expressed in seedling of rice and in the shoot and pistil of Arabidopsis. Analyses of gene expression on Ubi-1::BrCIPK1 rice lines was differentially accumulated by cold, salinity and drought, indicating its biological roles in the multiple stress response pathways in plants. Further, the expression of BrCIPK1 is hijacked by rice calcineurin-B-like protein (OsCBL5). Moreover, mRNA expression of P5CS1, a gene responsible for proline biosynthesis is regulated by the BrCIPK1 during abiotic stresses resulting to improved accumulation of proline. The interaction of BrCIPK1 with OsCBL5 along with the regulation of P5CS1 explained the enhanced tolerance of transgenic rice. This gene could be used in the development of rice varieties with enhanced tolerance to abiotic stresses.