간행물

한국육종학회 심포지엄

권호리스트/논문검색
이 간행물 논문 검색

권호

2013 한국육종학회-차세대BG21사업단 공동심포지엄 (2013년 7월) 243

1.
2013.07 서비스 종료(열람 제한)
Chili pepper (Capsicum annuum) is one of the most important vegetable crop for human being as a rich source of nutritions and spicy condiments. To make reference genome sequence of pepper, we sequenced the whole genome of Capsicum annuum, CM334 using Illumina/Solexa Genome Analyzer GA2. The genome size of CM334 is estimated as 3.5 Gb. A total of 716 Gb (205.96x coverages of the whole genome) of raw sequences were generated. After filtering out the low quality sequences, a total of 233 Gb (66.7x) of the raw sequences were used for assembly. Total assembled contig length and number were 2.93 Gb and 295,502, respectively. N50 and average length were 25.72 kb and 6,5 kb, respectively. By sequencial scaffolding with mate-pair sequences of 2 kb - 20 kb sizes, a total of 3.04 Gb of scaffold which is approximately 90% of the whole genome was assembled. The total number of scaffolds was 33,876 with N50 length of 1,605 kb. For annotation of the pepper genome, a total of 46 Gb of transcriptome sequences were generated from 12 different tissues using Illumina GA2 and Hi-seq 2000. We are under way of analyzing the characteristic traits of pepper using transcriptome data. The progress of pepper genome sequencing project including gene annotation, gene family analysis, comparative genomics studies on evolution of hot taste, genome expansion and fruit development will be presented in the meeting.
2.
2013.07 서비스 종료(열람 제한)
In the past half century, production of major food crops in the world has kept pace with the population increase. The yields of major cereals such as maize, rice and wheat have been more than doubled in most parts of the world and even tripled in certain countries. However, food production is facing even greater challenges in the next half century because of high demands in both quantity and quality, and ever increasing pressures on resources and environments. At the same time, advances in genomics, biotechnology and genetic studies have brought about unprecedented opportunities for crop genetic improvement. Rice is a major food crop feeding approximately half of the world’s population, and has provided a model system for cereal research. In my presentation, I will describe the demands for increased production for future needs, address the main issues that we have encountered as challenges, present current progress in rice functional genomics research, and provide prospect on how the advance in research can be translated into technologies and activities for rice genetic improvement.
3.
2013.07 서비스 종료(열람 제한)
Conifers have been the dominant tree species of many forests for more than 200 million years and are currently ecologically and economically extremely important species. Despite their importance there has, to date, been no gymnosperm genome sequence available. We produced a draft assembly of the 20 Gbp Norway spruce (Picea abies) genome. Ab initio gene prediction identified 28,354 well-supported genes representing a gene number similar to the >100 times smaller genome of Arabidopsis thaliana. Analysis of synonymous substitutions per synonymous site (Ks) identified no evidence of a recent whole-genome duplication suggesting that genome expansion resulted from other mechanisms. Repeat analysis showed that the large genome resulted from the slow and steady accumulation of a diverse set of LTR TEs that were not subsequently removed by unequal recombination, as evidenced by a high abundance of complete LTRs with few solo LTRs being identified. We performed low coverage sequencing of Pinus sylvestris, Abies sibirica, Juniperus communis, Taxus baccata and Gnetum gnemon to enable comparative analyses, revealing that the TE diversity is shared among extant conifers. Profiling of 24nt sRNAs, which are known to silence TEs via methylation, was highly tissue-specific and much lower than in other plants. We further identified numerous long (>10,000 bp) introns that arose due to TE insertions and that seem to be shared across gymnosperm species in addition to the genome containing numerous gene-like fragments, most likely representing pseudogenes. We additionally identified 13,031 spruce-specific and 9,686 conserved long non-coding RNAs, 2,719 miRNA candidates and show that the 21nt sRNA population is highly diverse, as reported previously for other conifer species. The availability of a conifer genome will enable further advances in conifer forestry and breeding as well as enabling evolutionary analysis including this previously missing group of land plants.
4.
2013.07 서비스 종료(열람 제한)
Fungal blast caused Magnaporthe oryzae, bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo), bacterial streak caused by Xanthomonas oryzae pv. oryzicola (Xoc) are devastating diseases of rice worldwide. Application of host resistance to these pathogens is the most economical and environment-friendly approach to solve this problem. Some major disease resistance (MR) genes controlling qualitative resistance and quantitative trait loci (QTLs) controlling quantitative resistance are valuable sources for broad-spectrum and durable disease resistance. We have characterized a number of rice MR genes and resistance QTL genes that confer a broad-spectrum or durable resistance to M. oryzae, Xoo, and Xoc. How to efficiently use these genes for rice improvement will be discussed.
5.
2013.07 서비스 종료(열람 제한)
The companion cells of the Arabidopsis thaliana egg and sperm, the central and vegetative cells, undergo active DNA demethylation prior to fertilization. However, its biological significance, extent of conservation, and targeting preferences are not yet clear. We recently showed that localized demethylation of interspersed, small transposable elements is a common feature of A. thaliana companion cells. The DEMETER DNA glycosylase encodes active DNA demethylase activity and is required for seed production. DME-mediated DNA demethylation in the central cell is required to establish imprinted gene expression in the endosperm, and is considered a master regulator for plant gene imprinting. However, the similarity among DME targets in the central and vegetative cells, despite their different functions and developmental fates, suggests that establishment of genomic imprinting may not be the basal function of DME. Lack of DEMETER in vegetative cells causes reduced methylation of transposons in sperm. Our observation suggests that the primary function of companion cell demethylation is to reinforce transposon silencing in plant gametes.
6.
2013.07 서비스 종료(열람 제한)
Flowering is exquisitely regulated by both promotive and inhibitory factors. Molecular genetic studies with Arabidopsis have verified several epigenetic repressors that regulate flowering time. However, the roles of chromatin remodeling factors in developmental processes have not been well explored in rice. We identified a chromatin remodeling factor OsVIL2 (O. sativa VIN3-LIKE 2) that promotes flowering. OsVIL2 contains a plant homeodomain (PHD) finger, which is a conserved motif of histone binding proteins. Insertion mutations in OsVIL2 caused late flowering under both long and short days. In osvil2 mutants OsLFL1 expression was increased, but that of Ehd1, Hd3a and RFT1 was reduced. We demonstrated that OsVIL2 is bound to native histone H3 in vitro. Chromatin immunoprecipitation analyses showed that OsVIL2 was directly associated with OsLFL1 chromatin. We also observed that H3K27me3 was significantly enriched by OsLFL1 chromatin in the wild type, but that this enrichment was diminished in the osvil2 mutants. These results indicated that OsVIL2 epigenetically represses OsLFL1 expression. We showed that OsVIL2 physically interacts with OsEMF2b, a component of polycomb repression complex 2. As observed from osvil2, a null mutation of OsEMF2b caused late flowering by increasing OsLFL1 expression and decreasing Ehd1 expression. Thus, we conclude that OsVIL2 functions together with PRC2 to induce flowering by repressing OsLFL1. Transgenic plants over-expressing OsVIL2 flowered early. In addition, they were taller and ticker due to increased in cell number, resulting in yield increase. The same phenotypes were observed from OsVIL4 knockout mutants. These indicate that OsVIL4 represses OsVIL2 function by directly binding to the protein.
7.
2013.07 서비스 종료(열람 제한)
During pathogen attack, the host plant induces genes to ward off the pathogen while the pathogen often induces host genes that increase susceptibility to the pathogen. Gene expression studies identified many soybean genes altered in expression in resistant and susceptible plant roots over time during infection by soybean cyst nematode (Heterodera glycines; SCN). However, it is difficult to assess the role and impact of these genes on resistance and susceptibility by using gene expression patterns alone, because the nematode injects proteins into the host. These nematode effector proteins interfere with and subvert the normal molecular mechanisms of the host cell. Therefore, we cloned >110 soybean genes from gene expression experiments using microarrays and RNA-Seq deep sequencing. The genes were overexpressed in soybean roots of composite plants to determine their impact on SCN development. Several overexpressed genes decreased the number of mature SCN females more than 50% at 32-35 days after inoculation; numerous other genes increased the number of mature females by more than 150%. Genes that reduced the number of mature females per plant by more than 50% when overexpressed, included genes encoding a β-glucanase, two lipases, calmodulin, a possible transcription factor, as well as proteins of unknown function. Four genes increased the number of mature SCN females more than 200%, while eleven more genes increased the number of mature SCN females more than 150%. Genes enhancing susceptibility included several transporters, pectate lyase, a Ca-dependent kinase and ACC oxidase. Our data support a role for auxin and ethylene in susceptibility of soybean to SCN. These studies highlight the contrasting gene sets induced by host and nematode during infection and provide new insights into the interactions between host and pathogen at the molecular level. Some genes that conferred resistance to SCN were also tested against the root-knot nematode (RKN), Meloidogyne incognita. Many of the genes that conferred resistance to SCN also conferred resistance to RKN. This demonstrated that the genes conferred resistance across genera and provides new strategies for developing broad resistance in plants to parasitic nematodes.
8.
2013.07 서비스 종료(열람 제한)
In 2012, the world population exceeded 7 billion and the need to address food security has never been greater. Achieving food security won’t be easy considering the megatrends of growing population, greater affluence, and increasing urbanization. Not only are more people demanding more food, but they want greater variety, including meat, dairy, fruits and vegetables. While demand for food is growing, farmers’ ability to increase productivity is facing unprecedented challenges. Scarcity of water, energy, and land is expected to define food production in the coming decades. Agricultural practices will also need to protect biodiversity through increasing productivity without expanding into natural ecosystems. Further exacerbating the situation is a changing climate that has led to higher temperatures and erratic weather patterns in some areas. Each day farmers face the challenge of growing more from less - increasing yields while protecting the environment by using less water, land, and energy. Global Agricultural Biotechnology companies like Syngenta have addressed these challenges through innovation in research and development by looking at the grower’s challenges holistically, including land, technology, and the community. The presentation will cover general R&D activities in an agricultural biotechnology company, which may differ from those in academic research institutes. Product safety and environmental considerations are integral to industry’s R&D work. To make earlier and better-informed decisions on which active ingredients or traits to move forward, normally companies begin safety trials early in the development process, facilitating timely engagement with regulators and other key stakeholders. Also to complement in-house expertise and bring in novel technologies which may or may not be used in agribusiness, companies are actively seeking value-adding partnerships and collaborations to bring exciting new offers to the grower. Development of a GM crop through all those activities mentioned above is quite a costly and lengthy process. My presentation will describe a typical process required for developing a GM crop in an agricultural biotechnology company from early discovery to commercialization to the market, which may give you a different perspective from academic point of view.
9.
2013.07 서비스 종료(열람 제한)
인삼은 음지성 작물인데 7~8월 고온기에 강광과 고온하에서 잎의 가장자리부터 피해를 받아 결국 고사하게 되는 고온장해(엽소)가 발생한다. 엽소 피해를 받은 인삼은 근중의 감소, 뿌리 조직의 스폰지화로 인해 홍삼제조 시 내공의 발생율이 증가한다. 기존에 육성된 천풍은 지하부 체형과 홍삼품질이 우수하나 엽소에 약하다. 반면 엽소에 강한 연풍은 지하부 체형과 홍삼품질이 불량한 단점이 있다. 이에 따라 엽소에 강하고 홍삼품질이 우수한 인삼 품종의 개발이 시급하다. 본 연구는 엽소에 내성으로 선발된 ‘선일’ 품종의 시기별 고온장해 발생율, 엽록소 형광반응, Fm/Fv 값 변화, 인삼 잎 조직의 큐티클 층의 분포와 두께, 광합성 특성 및 유효성분 분석 결과를 보고 하고자 한다.
10.
2013.07 서비스 종료(열람 제한)
In previous studies, we reported that a QTL for 1000-grain weight (TGW), qTGW3 was located in the interval between RM60 and RM523 (1.2Mb) on chromosome 3 using advanced backcross lines derived from a cross between Oryza sativa ssp. Indica cv. Milyang 23 and O. glaberrima. The O. glaberrima alleles at this locus increased TGW and GL in the Milyang 23 background. To further confirm and narrow down the position of the QTLs on chromosome 3, twenty lines with different O. glaberrima segments in the target region were selected. Twenty lines were evaluated for seven agronomic traits including 1,000 grain weight and grain length and also genotyped with ten SSR markers. Sixteen lines(A, B, C groups) with the O. glaberrima segment flanked by SSR markers, RM60 and RM7332 displayed significantly higher values than Milyang 23 in TGW and GL whereas four lines(D, E groups) without the O. glaberrima segment displayed no difference in TGW and GL. The result indicates that two QTL, qTGW3 and qGL3 are located near RM60 and RM7332.
11.
2013.07 서비스 종료(열람 제한)
The high temperature due to climate change may result in the intensification of several drought and heat stress on crops including potato. These abiotic stress affect on potato development staages; sprout development, tuber initiation and maturation. Potatoes need moderate amounts of nitrogen and cool night for good tuber growth. Especially, high temperature in soil will delay tuber initiation and induce malformation. Therefore, to identify quickly heat tolerant lines and breeding potato lines adapt to high temperature in the field are needed. The objectives of this study were as follows; To apply in vitro screening method for identifying potato lines adapted to high temperature conditions. To verify these results under field assays carried out under natural high temperature field conditions. We used in vitro screening methods with breeding lines from Intranational Potato Center(CIP) under three temperature regime, 18℃, 25℃ and 30℃. All breeding liens had some genotype that produced microtubers at 18℃ and 25℃, with a clear tendency for lower percentage of tuberization at the high temperature. To verify in vitro screening methods for heat tolerance lines, we carried out natural high temperature filed evaluation at Tacna, La Molina and Sanramon in Peru. The results of both the in vitro test and the field assay showed clear relationship and similar expression of tuberization percentage. This finding supports the use of the in vitro assay as a rapid screening methods that represents performance at the field level. But the correlation between performance of the breeding lines under the in vitro and field condions was low. This could be due to differential response to breeding lines to characteristics of the field environment, such as soil salinity, drought, which were not represented in the in vitro assay.
12.
2013.07 서비스 종료(열람 제한)
옥수수와 같은 1대교잡종 품종 육성을 위한 타가수정작물의 육종방법은 기본적으로 원종개발과 조합능력검정을 통한 교잡종 육성의 큰 틀에서 pedigree method등과 같은 전통적인 방법이나 분자육종의 최신기술이 이용되고 있다. Golden Seed Project의 시작으로 내수시장에만 머물고 있던 식량작물 육종기술이 해외시장에서 경쟁해야할 상황에 직면하게 되었다. 그 중 옥수수는 소수의 다국적 기업이 선점하고 있는 해외시장에서 수출액 170억원($1,500만USD)을 목표로 종자개발 계획이 작성되고 있다. 현시점에서 소수 다국적 기업의 최신 옥수수 육종기술의 현주소를 파악하여 Golden Seed Project의 목표 달성과 국내 옥수수 육종기술의 질적향상을 위한 방법을 모색하고자 한다. 인공자가수분을 통한 옥수수 원종 개발은 최소 S6세대까지 진행할 동안 동계온실세대촉진이나 아열대 동계포장을 이용하더라도 최초 교배조합작성으로부터 약 4년의 기간이 소요된다. 현재 파이오니어, 몬산토, 신젠타 뿐만 아니라 CIMMYT과 미국의 주립대학교등에서는 육종년한의 단축과 100% 동형접합체를 확보하기 위하여 배가반수체기술을 도입하여 이를 통한 원종개발을 하고 있다. 이 기술의 핵심은 자연적으로 배수체를 유도하는 옥수수endogenous genes과 반수체의 빠른 식별을 위한 표현형적 표지인자의 gene pyramiding을 통한 반수체 유도계통의 육성이다. 이미 위에서 언급한 회사 및 기관에서 반수체유도율 평균 8%정도의 몇몇의 유도계통들이 개발되어 있다. 이 기술을 통한 원종의 개발은 2년이다. 이 기술을 통해 한해 수천 개의 원종이 개발되는데 이렇게 많이 개발된 원종들에서 우수한 교잡종 생산을 위한 교배조합의 작성이 새로운 문제로 제기되고 있으며 이를 해결하기 위하여 genomic selection을 적극 이용하고 있다. Genomic selection에서는 QTL mapping이나 association mapping과 달리 각 표지인자의 효과에 대한 유의성 검정을 하지 않는다. 비록 각 표지인자의 추정육종가가 미미하더라 그 정보를 그대로 이용하여 양적유전형질 발현에 관련된 모든 polygenes의 효과를 추정함으로써 교잡종상태에서의 형질발현을 예측하고 파종전 genotyping을 통해 예측가가 우수한 교잡종만을 선발하여 파종하고 평가한다.
13.
2013.07 서비스 종료(열람 제한)
We are importing corn grains more than eight million tons every year, and self-sufficiency rate of corn is less than one percent. It is not easy to increase field corn production in Korea because of limited arable land. For this reason, many companies have been interesting overseas agriculture for corn production. But they don’t have enough suitable variety for the target area. Our objective is to develop field corn varieties for adaptation in Primorsky Krai which is the southeasternmost region of Russia. This project has been collaborated with Dr. Huk-Ha Lee in Seoul National Univ. and planted three times in Primorsky Krai since 2011. Planting materials for this project were developed in Maize Research Institute. 74 hybrids in 2011, 76 in 2012, and 80 in 2013 were planted for regional performance test. Primorsky Krai is a colder area and has less frost-free days than Korea. Several hybrids have shown good performance, but lots of materials developed in Korea could not fully ripened in 2011 because of late planting and early frost. In 2012, we mainly selected early flowering materials as well as picked materials from first year. The silking date of our materials was later than local commercial varieties, but some our hybrids had good characteristics and high yield. Among them, we picked two hybrids and planted them in Ussuriysk in Primorsky Krai for field demonstration test. We expect some of the selected hybrids can be candidate varieties for improvement of corn production at overseas agricultural production base.
14.
2013.07 서비스 종료(열람 제한)
오일의 산화적 안전성을 높이고 저장기간을 늘리기 위하여 수소를 첨가하여 액체 상태의 오일을 고체상태로 만드는 hydrogenation이란 방법을 마가린이나 쇼트닝을 만드는데 사용해 왔으나 이 과정중에 trans fat 이 생성되는 단점이 있다. 콩의 기름은 약 10% palmitic acid, 4% stearic acid, 17% oleic acid, 55% linoleic acid 와10% linolenic acid으로 구성된다. hydrogenation과정을 회피하여 콩 기름을 마가린 제조에 사용하기 위하여 mangosteen의 steroyl-ACP-thioesterase를 과발현 시킴과 동시에 콩의 palmitoyl-ACP thioesterase 와 delta 12 desaturase의 발현을 억제 함으로서 약 10-20%의 stearic acid 와 70-80%의 oleic acid를 갖는 콩을 생산 했으며. 이러한 지방산 조성은 또한 기후가 온난한 지역에서 바이오디젤의 원료로 사용되어 질수 있다. 어류의 소비는 급속히 증가 되고 있는 반면 재고량은 계속적으로 감소하고 있다. 양식이 어류의 공급을 증대시킬 대체수단으로 여겨져 왔으나 야생 잡어를 양식 어류의 사료로 사용함으로써 먹이사슬 하부에 존재하는 어류의 감소를 초래하여 결과적으로 야생 어류의 재고를 감소시키는 결과를 초래하였다. 따라서 기존의 양식사료를 대체할 새로운 사료의 개발이 절실한 상황이다. 우리는 콩을 이용하여 기존의 양식사료를 대체하려는 연구를 수행중에 있다. 콩이 양식어류의 사료로 사용되기 위한 중요한 요소중의 하나는 콩의 지방산 조성 및 함량으로 어류에 존재하는 지방산과 비슷한 조성 및 함량을 갖아야한다. 4개의 long chain omega 3 fatty acid 합성 관련 유전자와 3개의 astaxanthin 합성 관련 유전자를 집적함으로서 DHA (Docosahexaenoic acid)의 전구물질인 EPA (Eicosapentaenoic acid)를 5% 함유하며 연어의 양식에 사용되는 carotenoid의 일종인 astaxanthin을 종자 1g당 25ug 수준으로 생산하는 콩을 개발 했으며 이는 기존의 어류양식에 사용되는 사료를 대체하는데 사용되어 질수있다.
15.
2013.07 서비스 종료(열람 제한)
The transfer of a biotic resistance gene from indica rice cultivars into japonica cultivars by conventional breeding methods often difficult due to high sterility of the progenies, poor plant type, and linkage drag. Molecular markers provide opportunities to map resistance genes and accelerate the application of marker-assisted backcross(MAB) breeding through the precise transfer of target genomic regions into the recurrent parent. The basis of MAB breeding is to transfer a specific gene/allele of the donor parent into the recurrent parent genome while selecting against donor introgressions across the rest of the genome. The effectiveness of MAB breeding depends on the availability of closely linked DNA markers for the target locus, the size of the population, the number of backcrosses and the position and number of markers for background selection. We have successfully developed Bph18 version of the commercially cultivated japonica elite cultivar by using MAB and incorporating the resistance gene Bph18 that conferred enhanced resistance to BPH. MAB breeding provides a new opportunity for the selective transfer of biotic resistance genes into elite indica rice cultivars devoid of linkage drag. In additon, molecular markers precisely estimate the introgression of chromosome segments from donor parents and can speed up the recipient genome recovery via background selection.
16.
2013.07 서비스 종료(열람 제한)
Ginseng (Panax ginseng C.A. Meyer) is the most famous medicinal herb in East Asia. Although medicinal components and their functions have been widely investigated, ginseng has been regarded as an underdeveloped crop in genetics and genomics research areas. This study was conducted to elucidate the structure and evolution of the ginseng genome by analyses of expressed sequence tags (ESTs) and bacterial artificial chromosome (BAC) sequences. The EST analysis based on the calculation of synonymous substitutions per synonymous site (Ks) in paralog and ortholog pairs revealed that two rounds of polyploidy events occurred in the common ancestor of ginseng and American ginseng (P. quinquefolius L.) and subsequent divergence of the two species. The sequence analysis of repeat-rich BAC clones characterized the major component of the ginseng genome, long terminal repeat retrotransposons (LTR-RTs). The LTR-RTs were classified into five main families, of which three (PgDel, PgTat, and PgAthila) belonged to Ty3/gypsy and the other two (PgTork and PgOryco) to Ty1/Copia. High abundance of the LTR-RTs were revealed by whole genome shotgun (WGS) read mapping and fluorescence in situ hybridization (FISH) analysis. Particularly, the most abundant PgDel family have played major roles in expanding heterochromatic regions as well as remodeling euchromatic regions. Biased intensity of the PgDel2 FISH signals on half the total chromosomes demonstrates the allopolyploid feature of ginseng genome. Insertion time estimation of each LTR-RT implied that LTR-RTs have proliferated after the recent polyploidization of ginseng. These results suggest that the ginseng genome of the present day has been expanded and evolved by two rounds of polyploidization and accumulation of LTR-RTs.
17.
2013.07 서비스 종료(열람 제한)
The architecture of rice panicle is primarily determined by the arrangement of branches and spikelets, and it directly affects grain yield. We identified a mutant for panicle apical abortion from a japonica cultivar Hwacheongbyeo treated with N-methyl-N-nitrosourea. Under normal growth conditions, the mutant had multiple abnormal phenotypes, such as a slight reduction in plant height, narrow and dark green leaf blades, and small erect panicles with clear panicle apical abortion compared to the wild-type plants. Genetic analysis revealed that the panicle apical abortion was controlled by a single recessive gene, which is tentatively designated as paa. The paa gene was fine mapped at an interval of 71 kb flanked by STS markers aptn3 and S6685-1 at the long arm of chromosome 4. Sequence analysis of the candidate genes within the delimited region showed a single base-pair change corresponding to an amino acid substitution from glycine to glutamic acid. We expect that the paa gene will be a clue to uncover the molecular mechanism of panicle apical abortion and to maintain the panicle identity for grain yield in rice breeding programs.
18.
2013.07 서비스 종료(열람 제한)
Plant height is an important agronomic trait that affects grain yield. Previously, we reported a novel semi-dominant dwarf mutant, D-h, derived from chemical mutagenesis using N-methyl-N-nitrosourea(MNU) on a japonica rice cultivar, Hwacheongbyeo. In this study, we cloned the gene responsible for the dwarf mutant using the map-based approach. Fine mapping revealed that the mutant gene was located on the short arm of chromosome 1 in a 48 kb region. Sequencing of the candidate genes and rapid amplification of cDNA ends-polymerase chain reaction(RACE-PCR) analyses identified the gene, d-h, which encodes a protein of unknown function, but whose sequence is conserved in other cereal crops. Real-time (RT)-PCR analysis and promoter activity assay showed that the d-h gene was primarily expressed in the nodes and the panicle. In the D-h mutant plant, the gene was found to carry a 63-bp deletion in the ORF region, which was confirmed to be directly responsible for the mutant’s gain of a functional phenotype by subsequent transgenic experiments. Since the mutant plants exhibit a defect in the GA response, but not in the GA synthetic pathway, it appears that the d-h gene may be involved in a GA signaling pathway.
19.
2013.07 서비스 종료(열람 제한)
Sugarcane is one of the most efficient photosynthesizer in the plant kingdom, able to convert as much as 2% of incident solar energy into biomass. A large amount of lignocellulosic biomass such as leaf litter residues and bagasse are generated during the sugarcane harvest or after the sugar refining process, respectively. Therefore, lignocellulosic biomass from leaf and processing residues will likely become a valuable feedstock for biofuel production. However, higher temperatures and/or acid concentrations result in dehydration of xylose to furfural, and glucose to hydroxymethyl furfural, which act as inhibitors of the fermentation process. New pretreatment protocols are being developed that require the application of xylanases and other enzymes for maximal yields of xylose. Our objectives target the improvement of fermentable sugar yields from hemicellulosic sugarcane residues and enhancing the biosafety of the transgenic plants. We evaluated two transgenic approaches: lignin modification by RNAi suppression of the lignin biosynthetic gene COMT and in planta production of a hyperthermostable xylanase. More than 200 transgenic sugarcane plants were generated and lines with suppression or expression of the target genes were selected. RNAi suppression of COMT resulted in reduced lignin content and altered lignin composition. In planta produced xylanase Xyl10B converted the majority of sugarcane xylan to fermentable xylobiose. Performance and conversion efficiency of transgenic plants grown in replicated field plots under USDA-Aphis notification 11-040-120 will also be presented.
20.
2013.07 서비스 종료(열람 제한)
Seed germination and the establishment of young seedlings are critical phases in the plant’s life cycle. To control these processes, plants have evolved diverse hormonal signaling networks in which brassinosteroids (BRs) attenuate abscisic acid (ABA) responses; however, the underlying regulatory mechanism remains elusive. Here, we reveal that epigenetic silencing of the ABA signaling regulator ABI3 via the BR-related transcription factor BES1 is essential for the inhibitory effect of BRs on ABA signaling during early seedling development. BR-activated BES1 forms a transcriptional repressor complex with TPL via its EAR motif that recruits the histone deacetylase HDA19. This facilitates the histone H3-mediated deacetylation of ABI3 chromatin, leading to the suppression of ABI3 and its downstream target ABI5, which results in reduced ABA sensitivity. We propose that the BR-activated BES1-TPL-HDA19 repressor complex controls epigenetic silencing of ABI3 and thereby suppresses the ABA response during early seedling development.
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