본 리뷰의 목적은 벼 종자 저장단백질 구조분석 및 발현특성분석 결과 종합화를 통하여 종자형질 개선 등의 실용화연구를 위한 기반구축을 모색하는데 있다.
최근 벼 염색체염기서열완전해독 연구 결과를 이용한 유용형질 유전자 분리 및 실용화 연구가 많이 진행되고 있다. 특히 벼 종자 저장단백질은 인류에게는 주요 영양원으로 사용되어지며 종자 발아시에는 식물체 성장을 위한 질소원으로 사용되어진다. 벼 종자 저장단백질의 분류는 용매에서의 용해도에 따라 약산성 및 알카리 용해성의 glutelin, 알코올 용해성의 prolamin, 염 용해성의 globulin으로 나눈다. 벼 염색체 상에는 11개의 glutelin 유전자와 33개의 prolamin 유전자가 존재하며 prolamin 유전자의 경우 5번 염색체 15 Mb 부위에 15개의 유전자가 위치하였다. 이와 같이 종자저장단백질 유전자들이 동일 염색체 부위에 위치하고 있는 것은 진화학적으로 동일 염색체에서 유래하였거나 유사한 유전자발현 조절영역을 가지고 있음을 의미한다. Globulin 유전자는 5번 염색체에 단일 유전자로 존재하였다.
마이크로어레이를 이용한 종자저장 단백질 관련 유전자의 조직 특이 발현 양상을 분석한 결과 glutelin과 대다수의 prolamin 합성 유전자는 종자배유에서만 발현을 하였으며 소수의 prolamin과 globulin 합성 유전자는 종자배유와 발아종자에서도 발현을 나타내었다. 종자 저장단백질의 프로모터부위를 분리한 후 종자에서의 발현 양상을 분석한 결과 glutelin type C1 프로모터가 종자의 전체 부위에서 발현을 나타내었으며 glutelin type B5와 α-globulin 프로모터가 많은 양의 발현을 나타내었다. 본 리뷰를 통하여 벼 종자 저장단백질의 구조및 발현특성 연구 진행사항을 살펴보았다. 이러한 연구 동향분석은 종자형질 개선 및 물질생산 등의 실용화 연구를 수행하는 연구자들에게 최근의 연구 현황을 제공할 수 있을 것으로 생각된다.
Perilla is a annual herb plant of the mint family, Laminaceae and mainly cultivated in eastern Asia, i.e. Korea, China and Japan. In response to an increased interest for healthy supplement food from the public, people are focusing on the properties of perilla. The applicable parts of perilla plants are the leaves and seeds. Perilla has been cultivated as a source of unsaturated fatty acid oil. But in spite of advantage of the important nutritional traits the genome or molecular studies on perilla remains largely unknown. Sequence comparisons of chloroplast (cp) genomes or nuclear ribosomal DNA (nrDNA) are of great important to provide a evidence for taxonomic studies or species identification or understanding mechanisms that underlie the evolution of perilla species. So, we tried to study a structural analysis of perilla genome and 45s nrDNA using 9 species (3 Diploid; Perilla B-17, P. hirtella, P. setoyensis / 6 Tetraploid; YCPL 285, YCPL 170, YCPL 205-1, YCPL 181-1, YCPL 177-1, YCPL 207-1). The complete cp genome and nrDNA of 9 perilla species were determined using Illumina sequencing technology and analyzed on the variance in base level between perilla B-17 and salvia miltiorrhiza. Total chloroplast genome size of perilla B-17 as a reference was 152,589 bp in length. We also identified an slightly overlapped intergenic regions between salvia miltiorrhiza and B-17. The results above will contribute to growing of molecular or genome structure and functional genomics of perilla available in studying perilla biology.
For further study, we will look for genetic diversity of perilla species.
The next-generation sequencing(NGS) technology is being used for more effective genetic mapping. In previous study, we obtained 60x coverage of sequence from Milyang23 and Gihobyeo on average comparing with Nipponbare reference genome. Also, we developed new derived cleaved amplified polymorphic sequence(dCAPS) markers based on the single nucleotide polymorphisms(SNPs) in coding region sequence(CDS) between these varieties. Totally, 1,726,798 SNPs between Milyang23 and Gihobyeo were detected. Among them, 146 SNP were selected for making dCAPS markers and located on genetic map with previously reported 219 PCR-based DNA markers. The map was applied to the detection of quantitative trait loci(QTLs) for stem internode diameters, culm length and panicle length within MGRIL population, and six QTLs with relatively high LOD score were found at three chromosomes; culm length and stem diameter including the first internode diameter, third and fourth internode diameter.
This study showed that the NGS allowed the rapid discovery of a large number of SNPs for dCAPS marker. So, we tried to find out more single nucleotide polymorphisms(SNPs) which were located on the whole genome sequence, such as un-translated region(UTR), intron, Inter-region and coding region sequence(CDS) between Milyang23 and Gihobyeo varieties. And we collected phenotypic information about culm length, panicle length, four stem internode diameters and panicle number in rice MGRIL population for QTLs. Furthermore, results of QTL analysis described above will shows relevance of molecular markers in mapping genes for useful breeding.
Genome sequencing researches for considerable numbers of crops and wild plants are being developed. Cytogenetic researches according to chromosome number and size are essential to confirm and comprehend ploidy level and genome size before genome sequencing project is actually conducted. Cytogenetic researches on six food crop plants were carried out by DAPI staining and fluorescence in situ hybridization (FISH) method. Fagopyrum esculentum Moench showed 2n=2x=16, each chromosome length of 1.42㎛ to 1.77㎛, total chromosome length of 13.31㎛, and karyotypic formula of 2n=8m; Phaseolus angularis W.F. Wight, 2n=2x=22, 2.01㎛ to 3.84㎛, total 28.03㎛, 2n=9m+2sm, Perilla frutescens var. japonica Hara, 2n=2x=40, 1.73㎛ to 2.76㎛, total 44.36㎛, 2n=5m+13sm+2st. Chromosome sizes of the other three species such as, Panicum miliaceum L., 2n=2x=36, total chromosome length of 30.83㎛, Sesamum indicum L., 2n=2x=26, 27.39㎛, lpomoea batatas L., 2n=2x=30, total 33.51㎛ were too small for each chromosome type to be identified and analyzed. The result of FISH analysis using 5S and 45S rDNA probe showed species-specific chromosome locations in the genome. These preliminary analyses were carried out to decide which food crop to prioritize for genome sequencing. This work was supported by the “Cooperative Research Program for Agriculture Science & Technology Development (No.PJ009837), Rural Development Administration, Republic of Korea.
The next-generation sequencing (NGS) technology is being used for more effective genetic mapping and genome analysis. In this study, we performed whole-genome sequencing on the genomic DNA of Milyang23 and Gihobyeo using NGS and developed new cleaved amplified polymorphic sequence (CAPS) markers based on the single nucleotide polymorphisms (SNPs) in coding sequence between these varieties. Approximately, sequences of 60x coverage of the Nipponbare reference genome on average were obtained following Illumina sequencing. Totally, 1,726,798 SNPs between Milyang23 and Gihobyeo were detected. Among them, 149 SNP were selected for CAPS markers and located on genetic map with previously reported 219 PCR-based DNA markers. This map was applied to the detection of quantitative trait loci (QTLs) for stem internode diameters, culm length and panicle length in rice with MGRIL population. Newly 6 QTLs were detected for culm length (CL) and stem diameter (ID) traits including the first internode diameter (I1D), third internode diameter (I3D), and fourth internode diameter (I4D). Among those QTLs, qI1D5 and qCL5 had relatively higher LOD score and explained 8.99% and 4.24% of total variation. This study showed that the NGS allowed the rapid discovery of a large number of SNPs for CAPS marker. Only very small portion of SNPs through re-sequencing were used in this study. Furthermore, the results of QTL analysis described above shows relevance of molecular markers in mapping genes for useful traits.
It is well known that Dharial (Bangladesh origin and weedy rice line) has longer seed longevity than indica and japonica rice varieties. To study the genetic basis of seed longevity of Dharial, we developed 240 BC3F7 backcross recombinant inbred lines derived from the crosses between Dharial (a donor parent) and two korea rice accessions (recurrent parents) including Ilmi and Gopum, respectively. Among these lines, we selected two introgression lines with longer seed longevity and named them Ilmi-NIL and Gopum-NIL. Also, we developed an EMS-induced mutant line from Dharial which has shortened seed longevity, and named it Dharial-EMS. We performed re-sequencing of four rice accessions that are Dharial, Dharial-EMS, Ilmi-NIL, and Gopum-NIL. A total of 706×106 raw reads were generated which provided sequence data over 46x rice genome coverage per each accession. We did genome-wide variation analysis comparing produced re-sequencing data and the re-sequencing data of Ilmi from NABIC database with the Nipponbare reference sequence. By graphical analysis of SNP distribution in rice genome of the five accessions, we could select candidate chromosomal segments introgressed from Dharial in Ilmi-NIL and Gopum-NIL. The introgressed chromosomal segments were in seven regions in Ilmi-NIL and eight regions in Gopum-NIL, and four common introgressed regions between Ilmi-NIL and Gopum-NIL were identified. 2,758 SNPs between Dharial and Dharial-EMS were found in the introgressed regions. Also, we detected 450 genes including at least one SNP among these SNPs. This result will facilitate identification of genes and development of molecular markers for improvement of seed longevity.
In plants, the Dof (DNA binding with One Finger) proteins are plant-specific transcription factors with a particular class of zinc-finger DNA-binding domain. The Dof genes have been predicted 30 different Dof genes in the rice Oryza sativa genome by phylogenetic analysis. The mostly Dof proteins contain a conserved region of 50 amino acids with a C2-C2 zinc finger motifs that binds a cis-regulatory element sequence 5’-T/AAAAG-3’. We found that a member of the DOF transcription factor family, Dof1 gene of rice, was expressed to wound from Ds insertion mutant population. Sequencing of the flanking regions of the transposon insertion site indicated that the gene-trap had been inserted near the front of the second exon of OsDof1 gene in chromosome 7. Genomic southern analysis revealed that mutant line contained a single copy of Ds gene trap. The Ds tagged rice mutant line, OsDof1::Ds, wound-inducible GUS expression was identified. To analyze the cis-acting elements, we constructed fusion genes with the OsDof1 promoter fused to the β-glucuronidase (GUS) reporter gene and transformed Arabidopsis and rice plants with these constructs. Wound-induced GUS expression was observed in the leaves of transgenic OsDof1::GUS rice and Arabidospsis plants. These results showed that, OsDof1 protein might be involved in stress responses and growth regulation in plant, might plays a role as a transcription regulator in stress response signal transduction pathways of plant.