Genetic Analysis of Rice Mutants Identifies a New Locus at the Pi-ta Region Controlling Pathogen Recognition

Understanding the molecular mechanisms of host and parasite interactions should facilitate the development of novel strategies to control plant diseases. Host interactions with biotrophic and hemi-biotrophic pathogens are known to follow a gene-for-gene specificity. The plant expresses a resistance （R） gene that is effective in preventing disease in response to pathogen races expressing the corresponding avirulence gene. We are studying the interaction mechanisms of the R gene, Pi-ta, in rice with the corresponding avirulence gene, A VR-Pita, found in the hemi-biotrophic pathogen, Magnaporthe oryzae （formerly Magnaporthe grisea）. Pi-ta is a putative cytoplasmic receptor with a centrally localized nucleotide-binding site and leucine rich domain at the carboxyl terminus （Bryan et al., 2000; Jia et al., 2000）. AVR-Pita is predicted to be a metalloprotease （Jia et al., 2006b）. The putative processed protein, AVR-Pita176, has been shown to interact with the Pi-ta protein （Bryan et al., 2000; Jia et al., 2000）.     

Functional Analysis of DHS by Virus-induced Gene Silencing in Nicotiana benthamiana

With the progress in plant genomics research, the study direction is turned into the discovery and functional analysis of important genes. But an effective method is needed to investigate the biological function of eDNA sequences in large-scale （Wang et al., 2005）. With the newly developed technique-virus-induced gene silencing （VIGS）, plants infected with virus vector carrying host-derived sequence inserts will show loss-of-function or reduced-expression mutants in the host gene. The symptoms will tell the functional information of the gene （Liu et al., 2004; Burton et al., 2000）. Normally the process of constructing a virus vector and monitoring symptoms on infected plants can be completed within a few weeks, such that VIGS provides a simple, rapid and high throughput means of analyzing the function of sequenced genes.     

Development of Elongated Uppermost Intemode CMS Lines for Hybrid Rice Breeding in India

Development of cytoplasmic male sterile （CMS） lines with elongated uppermost internode （EUI） trait provides a genetic option to eliminate the use of GA3 in hybrid rice. During the past two decades, extensive work has been carried out on the subject that resulted in identification of several mutants with EUI trait for use in developing cytoplasmic/thermo-sensitive genic male-sterile lines with complete panicle exsertion （Okuno and Kawai, 1978; Rutger and Carnahan, 1981; Shen et al., 1987; Yang et al., 2000; 2002; Gangashetti et al., 2004）. Two recessive genes （eui-1 and eui-2） mapped on chromosome 5 and 10 respectively have so far been reported to control the internode elongation in rice （Librojo and Khush, 1986; Yang et al., 2001; Ma et al., 2004）. Considerable progress has been made in China in exploiting ＇eur gene for development of hybrid rice parental lines （Yang et al., 2000; 2002; Zhang et al., 2002）.     

Identification of AFLP Makers Linked to Early-Bearing Gene in Walnut

Amplified fragment length polymorphism （AFLP）, a novel DNA fmgerprinting technique based on polymerase chain reaction （PCR） with high discriminatory power, has the advantages of high efficiency, rapidness, reliability, and rich polymorphism et. It has been widely used for screening molecular markers, constructing genetic linkage map, analyzing relationship and locating genes （Vos et al., 1995）. However, due to high price of reagents involved in AFLP and requirement of high technology, its potential use has been limited. For walnuts, there are two groups characterized with early-bearing and late-bearing trait, respectively. Early-bearing walnuts ramify early with short intemodes, and begin to blossom and bear fruits in the first or second year or so. Studies show that the gene associated with the early-bearing character is a kind of precious genetic resource in nature and has very high hereditable ability （Zheng et al., 2003; Yamamo et al., 1998; Fang et al., 1999）. Research and employment of this has important meaning not only for the varieties improvement of walnuts, controlling and realizing of earlybearing quality, but also for the studies of flower bud differentiation in fruit trees. This research, combined AFLP technology with bulked segregant analysis （BSA） to screen AFLP markers linked to early-bearing character in walnut, can be applied to early screening of walnut hybrids, constructing genetic linkage map, locating genes and improving varieties.     

Comparison of QTL for Grain Number per Panicle in Three Populations Sharing 3 Parents and Fine Mapping of Gnlc

Complex traits, such as yield components, are inherited in a quantitative manner and typically controlled by quantitative trait loci （QTL）. Grain number per panicle （GN） is an important component of yield in rice and has been studied for QTL mapping in our lab （Yu et al., 1997; Xing et al., 2002）. Further discovery of QTL for GN and fine mapping will provide rich of gene resources for high yield breeding by marker assistant selection. Gene cloning is helpful to understand the biological mechanism underlying GN and instruct the application of gene engineering in rice yield breeding. In recent years, near-isogenic lines （NILs） for grain number have been reported for gene fine mapping （Tian et al., 2006; Zhang et al., 2006） and gene cloning （Ashikari et al., 2005）. However, so far, this kind of research is insufficiency for systematically elucidating the genetic bases and regulatory mechanism involved in GN. In this study, we compare the locations and genetic effects of QTL for GN detected in three sets of recombinant inbred line populations （RILs） sharing three parents, and fine map a new major QTL, Gnlc, commonly detected in the 3 populations.     

AFLP Analysis of Mitochondrial DNA from a Cytoplasmic Male Sterility Line and its Maintainer in Pepper （Capsicum annuum L.）

Cytoplasmic male sterility （CMS） is a maternally inherited trait characterized by the inability of a plant to produce functional pollen, which is widespread among higher plants. CMS system is a valuable tool for plant brc, ders to utilize in hybrid seed production and for molecular biologists to study the interaction between nuclear and mitochondrial genomes. Investigations into the molecular mechanism of CMS in several species have revealed that the incompatible nuclear-mitochondrial interactions leading to new chimeric mitochondrial genes such as T-urfl3 for Texas male sterility cytoplasm in maize, pcfin petunia, orf522 in sunflower, orf107 in sorghum and orf244 gene in Brassica may be responsible for CMS （Dewey et al., 1986; 1987; Young and Hanson,1987; Nivison and Hanson, 1989; Kohler et al., 1991; Moneger et al., 1994; Tang et al., 1996; Handa et al., 1995; Singh and Brown, 1991）.     

Salicylic Acid Induced Self-excision of the Marker Gene npt II Using CreloxP System from Transgenic Tobacco

Transgenic plants, despite a great deal of scientific evidences, have induced a number of environmental and consumer concerns for long time because various antibiotic resistance genes, according to common transformation strategies, will accompany engineered crops at all times. Several approaches, which have proven feasible, have been developed to excise marker genes from transgenic plants. The Cre-loxP site-specific recombination system from bacteriophage P1, which express the Cre protein to result in recombination between loxP sites, is one of the strategies mostly eliminated selectable marker in transgenic plants （Chen et al., 2003; Chen et al., 2004）. Either the transient expression or an inducible factor to turn on the expression of cre gene is existed in current Cre-loxP excision system. It requires crossing with a recombinase-expressing line and does not optimize to be functional for clonally propagated crops. Therefore, the strategies of self-excision of selectable markers mediated by CreloxP recombination system are coming to front （Cuellar et al., 2006; Mlynarova and Nap, 2003; Yuan et al., 2004; Zhang et al., 2006）.     

Genetic Dissection, Marker-assisted Introgression, and Pyramiding of Agronomic Traits in Rice

Through the efforts of the International Rice Genome Sequencing Project, the whole genome sequence office has been decoded （International Rice Genome Sequencing Project, 2005）. This sequence information has provided new tools for genetics and has created a new paradigm of plant breeding. Many phenotypic traits of economic interest are controlled by multiple genes and often show complex and quantitative inheritance： Recent progress in rice genomics has had a great impact in the genetic dissection of such traits into single genetic factors. Such genetic factors can subsequently be identified at the molecular level by map-based strategies （Yano, 2001）. So far, we have identified several genes involved in heading date （Yano et al., 2001）, field resistance to rice blast, cool temperature tolerance （Takeuchi et al., 2001） and pre-harvest sprouting （Takeuchi et al., 2003）, and genetic dissection of root morphology and yield-related traits is progressing. Working from the current status of genetic dissection, we have begun marker-assisted introgression of particular genes of interest into elite rice cultivars in Japan. Exploitation of economically important genes in natural variants will be essential to enhance the potential of new breeding strategies.     

Gene Identification and Reaction of Rice Varieties to Korean and Philippine Races of Xanthomonas oryzae. pv. Oryzae

Bacterial blight （BB） caused by Xanthomonas oryzae pv. Oryzae （Xoo） is one of the most serious diseases of rice. Ten races of the bacterium have been identified in the Philippines. Each race has specific virulence to varieties with different resistance genes, showing a gene-for-gene relationship in the host-pathogen interaction （Lee et al., 2003）. So far, twenty-nine major genes have been identified （Lee et al., 1999）. Due to emergence of the new races and genetic vulnerability of resistant varieties, the spreading of bacterial blight disease occurrence is increasing now in all areas of Korea. This study was carried out to find the gene identification and reaction of rice varieties to Korean and Philippine races ofXanthomonas oryzae, pv. oryzae.     

不同产地杉木种子游离氨基酸含量的初步分析

不同产地杉木种子均含有17种游离氨基酸，这与其它种子所含游离氨基酸种类基本一致。不同产地杉木种子游离氨基酸总量的变异趋势不同于杉木种子形态及发芽率的变异趋势。但其中某些氨基酸的变异趋势与种子发芽率呈负相关，表明杉木种子的发芽率可能与种子所含的某些游离氨基酸有关。不同产地杉木种子游离氨基酸总含量与干湿度指数呈负相关，说明杉木种子游离氨基酸总含量的地理变异亦可能是气候的差异所引起。     

外源有机酸对荞麦幼苗铝毒害的缓解效应

研究了外源有机酸对荞麦(Fagopyrum esculentum Moench)幼苗铝毒害的缓解效应，结果表明，0.4 mmol·L^-1的铝溶液能够显著抑制荞麦根的伸长，降低根系活力，增加叶细胞电解质渗漏率和丙二醛含量。铝溶液中加入不同浓度（0.2、0.4、0.8和1.2 mmol·L^-1）的草酸、柠檬酸或苹果酸后，以上伤害均减轻。用羊毛铬青R比色法检测表明，外源有机酸可以降低植物体各部位铝的含量。推测外源有机酸通过络合作用可以减少了根际和植物体内的铝数量，以达缓解铝毒害的目的。     

Genetic Algorithms and Ultravoilet Spectroscopy as Applied to Multicomponent Analysis of Amino Acids

Modified Genetic algorithm (GA) was proposed for simultaneous multicomponent analysis of ultraviolet spectroscopy is of four amino acids Tyr, Trp, Phe and Dhp.     

油菜转录因子BnZFP基因的分离及其功能初步分析

为克隆油菜ZFP类转录因子基因,初步阐明其功能。采用RT-PCR的方法克隆基因和体内检测;花沾法转化拟南芥,Northern blotting检测转基因后的表达。从甘蓝型油菜中分离了一个新的ZFP类转录因子,它编码377个氨基酸,与拟南芥AtZFP基因(At2g29660)的碱基序列相似性最高,为76.2%,命名为BnZFP。该基因在父本、母本和F1代不同发育时期中均能较稳定的表达;该基因转化拟南芥,对获得的转BnZFP基因拟南芥进行了Northern Blotting分析,表明该基因在拟南芥中得到过表达;与野生型拟南芥相比较,过表达BnZFP的转基因拟南芥在萌发、营养生长及生殖生长过程中没有表现出明显的表型变化,该基因的功能有待进一步研究。     

滇牡丹(Paeonia delavayi)二氢黄酮醇4-还原酶基因的鉴定及表达

为了研究二氢黄酮醇4-还原酶基因(DFR)对滇牡丹(Paeonia delavayi)花瓣中花色形成的作用,本研究采用RT-PCR技术首次从滇牡丹中克隆得到一个具有完整开放阅读框的二氢黄酮醇4-还原酶基因(PdDFR),生物信息学分析和转录模式分析显示,该基因全长1 050 bp,共编码349个氨基酸,其蛋白序列与黄牡丹(Paeonia lutea) DFR的蛋白序列具有99.00%的一致性。序列比对分析显示PdDFR基因存在一个由21个氨基酸组成的NADPH结合位点"VTGATGYIGSWLVKTLLERGN"。滇牡丹PdDFR蛋白与黄牡丹(Paeonia lutea, ALX35996.1)、蓖麻(Ricinus communis, XP015577076.1)、木薯(Manihot esculenta, XP021607-041.1)的DFR蛋白聚为一类;转录模式分析表明PdDFR基因在红色花瓣中有表达,在根、茎、叶中不表达。本研究通过对滇牡丹转录组数据的分析,分离并克隆得到PdDFR基因,为利用基因工程技术选育优良滇牡丹花卉品种提供理论参考。     

不同青稞品种风味物质分析

为探究不同青稞品种原料风味物质成分,采用气相色谱-质谱联用技术对8个不同青稞品种挥发性成分进行分析鉴定。结果表明,8个青稞品种的风味物质共检测出40种化合物,包括醛类10种、醇类8种、酯类2种、酮类5种、酸类3种、芳香类4种、烃类4种、呋喃类1种、酚类1种和其他类2种。不同青稞品种中相对含量最高的为醛类12.98%~58.09%,其次是酸类3.99%~33.90%,醇类6.88%~16.36%,酮类4.47%~12.78%。分类分析表明,8个青稞品种可分为两大类,‘勾芒紫青稞'、‘隆子黑青稞'、‘1127'、‘山青9号'和‘藏青320'相似度较高,为一类,‘藏青2000'、‘藏青25'和‘喜拉22'相似度较高,为一类,欧式距离为25时,两大类才能归为一类。     

不同有机酸对烤烟品质和产值的影响

采用大田试验研究了苹果酸、油酸和腐殖酸对烤烟品质指标及产值效果的影响。结果表明, 3种有机酸能明显提高烟叶中P素、K素、总糖、还原糖含量、钾氯比和糖碱比值, 以及糠醛、苯甲醛、茄酮、巨豆三烯酮和新植二烯等主要香气成分的含量, 改善烟草的香吃味。同时不同程度地降低烟叶中N素、淀粉、蛋白质、烟碱和氯离子的含量, 从而协调和平衡烟叶中的化学成分, 改善烟叶的品质。其中, 苹果酸的效果最佳, 腐殖酸和油酸次之。苹果酸可明显提高烤烟的均价和上中等烟的比例, 腐殖酸可明显提高烤烟的产量、产值及上中等烟的比例。     

高羊茅光周期调控基因CONSTANS的克隆与分析

本研究以坪用型"黔草1号"高羊茅为实验材料,基于多年生黑麦草CONSTANS(CO)基因序列设计引物,利用3'RACE和5'RACE方法扩增CO基因。结果表明,从高羊茅中分离出CO基因,命名为FaCON-STANS。经序列分析,cDNA全长1557bp,编码376个氨基酸,具有完整的开放阅读框(ORF,166～1296bp),氨基端具有B-box型锌指结构域,碳端具有CCT(CO,CO-like,TOC1)结构域。进一步的同源性分析表明,Fa-CONSTANS蛋白与禾本科植物的CO蛋白亲缘关系较近,与其它植物的亲缘关系较远。     

陆地棉一个丝氨酸/苏氨酸激酶蛋白基因的克隆与表达分析

通过RT-PCR获得一个编码棉花丝氨酸/苏氨酸激酶类似蛋白全长的cDNA片段,其编码的氨基酸序列与拟南芥ATPK3的相似度达到82%,这个基因暂被命名为GhPK1。基因全编码区包括1038个核苷酸,编码346个氨基酸的蛋白。GhPK1的编码产物在265~270个氨基酸处有一个跨膜区并可能结合在内质网膜上。GhPK1在种子和纤维中的表达水平较其它组织高。另外,GhPK1的表达量在受到盐胁迫后上升,说明GhPK1可能参与了盐胁迫反应。     

蓖麻AP2/ERF转录因子家族的生物信息学分析

AP2/ERF家族是一种广泛存在于植物体内的重要转录因子,该转录因子大多数参与植物的生长发育、生理代谢以及抵抗非生物胁迫的过程。本研究利用蓖麻基因组数据库寻找到了113个蓖麻AP2/ERF家族基因,利用生物信息学方法对这113个蛋白序列构建无根进化树,且对氨基酸组成成分进行分析,发现组成蛋白质的氨基酸数目在不同亚族之间差异较大,其中AP2亚族的平均氨基酸数目为个439,亚族中最小的平均氨基酸数目为ERF亚族,平均为255个。在蓖麻的113个蛋白序列中大部分为稳定的亲水性蛋白、且含有多个磷酸化位点、在该蛋白中α—螺旋和无规则卷曲是主要的二级结构方式,除AP2亚族外,其余亚族均含有β—转角,亚族无规则卷曲均占50%以上,说明延伸链和(β—转角则分散在整个氨基酸链中。三级结构与二级结构预测一致。还对保守结构域、蛋白无序化特性等进行了预测和较为全面的分析。这些分析结果为进一步研究蓖麻中AP2/ERF转录因子对生长发育过程中的作用提供了理论依据。