Characterization of enhancer trap and gene trap harboring Ac/Ds transposon in transgenic rice

INTRODUCTIONAfterthewholericegenomewassequencedsuccessfully,moreandmoregenescanbepredictedwithdifferentsoftwaresandannotationsystem.However,thefunctionsofpredictedgeneshavetobefurtheridentifiedbybiologicalanalysis.Oneofthemostpowerfulmethodsassigningfunctiontogeneisthroughinsertionmutagenesiswithtrans-posableelementasDNAsequencetag.Ac/Dstrans-posonsystemhasbecomeaverypopulartoolforgenetaggingandfunctionalgenomicsinvariousplantspecies(Altmannetal.,1995;Chinetal.,1999;Enokietal.,1999;Gre…     

Characterization of enhancer trap and gene trap harboring<Emphasis Type="Italic">Ac/Ds</Emphasis> transposon in transgenic rice

Insertion mutagenesis has become one of the most popular methods for gene functions analysis. Here we report a two-elementAc/Ds transposon system containing enhancer trap and gene trap for gene tagging in rice. The excision ofDs element was examined by PCR amplification. The excision frequency ofDs element varied from 0% to 40% among 20 F₂ populations derived from 11 differentDs parents. Southern blot analysis revealed that more than 70% of excisedDs elements reinserted into rice genome and above 70% of the reinsertedDs elements were located at different positions of the chromosome in rice. The result of histochemical GUS analysis indicated that 28% of enhancer trap and 22% of gene trap tagging plants displayed GUS activity in leaves, roots, flowers or seeds. The GUS positive lines will be useful for identifying gene function in rice. Project supported by the Hi-Tech Research and Development Program (863) of China (No. 2002AA2Z1003)     

Comparative mapping of QTLs for Al tolerance in rice and identification of positional Al-induced genes

INTRODUCTION Aluminum (Al) toxicity is one of the mostimportant yield-limiting factors for crop grown onacid upland and lowland acid sulphate soils (IRRI,1978). Al toxicity results in a reduced and damagedroot system, which in turn causes the affectedplants to be susceptible to drought stress and min-eral nutrient deficiencies (Foy, 1988). The physio-logical and biochemical mechanisms of the toxiceffect of Al on root elongation had been extensivelyinvestigated (Matsumoto, 2000). T…     

Comparative mapping of QTLs for Al tolerance in rice and identification of positional Al-induced genes

Aluminum (Al) toxicity is the major factor limiting crop productivity in acid soils. In this study, a recombinant inbreed line (RIL) population derived from a cross between an A1 sensitive lowland indica rice variety IR1552 and an Al tolerant upland japonica rice variety Azucena, was used for mapping quantitative trait loci (QTLs) for A1 tolerance. Three QTLs for relative root length (RRL) were detected on chromosome 1, 9, 12, respectively, and I QTL for root length under Al stress is identical on chromosome I after one week and two weeks stress. Comparison of QTLs on chromosome 1 from different studies indicated an identical interval between C86 and RZ801 with gene(s) for Al tolerance. This interval provides an important start point for isolating genes responsible for A1 tolerance and understanding the genetic nature of Al tolerance in rice. Four Al induced ESTs located in this interval were screened by reverse Northern analysis and confirmed by Northern analysis. They would be candidate genes for the QTL.     

Cloning and characterization of a glucose 6-phosphate/phosphate translocator from Oryza sativa

INTRODUCTIONNongreenplastidsofheterotrophictissuesarecarbohydrate importingorganellesand ,inthecaseofamyloplastsofstoragetissues,thesiteofstarchsynthesis.Investigationofwholetissuesfromavarietyofstarchsynthesizingcropplantsindicatedthathexoseunitswereimpo…     

Cloning and characterization of a glucose 6-phosphate/phosphate translocator from Oryza sativa

Plastids of nongreen tissues import carbon as a source of biosynthetic pathways and energy, and glucose 6-phosphate is the preferred hexose phosphate taken up by nongreen plastids. A cDNA clone encoding glucose 6-phosphate/phosphate translocator (GPT) was isolated from a cDNA library of immature seeds of rice and named as OsGPT. The cDNA has one uninterrupted open reading frame encoding a 42 kDa polypeptide possessing transit peptide consisting of 70 amino acid residues. The OsGPT gene maps on chromosome 8 of rice and is linked to the quantitative trait locus for 1000-grain weight. The expression of OsGPT is mainly restricted to heterotrophic tissues. These results suggest that glucose 6-phosphate imported via GPT can be used for starch biosynthesis in rice nongreen plastids.     

Isolation and physiological characteristics of a premature senescence mutant in rice （Oryza sativa L.）

A rice pse(t) (premature senescence, tentatively) mutant line, was isolated from 4500 independent T-DNA inserted transgenic lines. The symptoms of premature senescence appeared more severely than those of the control plants (Zhonghua 11,japonica) at the last development stage. To characterize the mutant and provide basic information on the candidate genes by mapping to a physical region of 220-kb, experiments were carried out in two phytotrons under controlled temperature of 24 ℃ and28 ℃, respectively. The content of chlorophyll, soluble protein and MDA (malondialdehyde), net photosynthesis, the antioxidant enzyme activities of SOD (superoxide dismuase) (EC 1.15.1.1) and POD (peroxidase) (EC 1.11.1.7) and the peptidase activities of leaves were measured from top to bottom according to the leaf positions at the flowering stage. Compared with the control plant,the mutant showed the following characteristics: (1) Higher net photosynthesis rate (Pn) appeared in the 1 st and 2nd leaves, contents of chlorophyll and soluble protein were also higher in the 1 st leaf; (2) The activities of SOD, POD and peptidase were higher according to the leaf position from top to bottom; (3) The symptom of premature senescence was accelerated in the mutant at 28℃treatment. The MDA content and the SOD and POD activities between the 24 ℃ and 28 ℃ treatment mutants were not significantly different. Content of chlorophyll and soluble protein of leaves mutant decreased rapidly at 28 ℃ treatment. The results show that pse(t) is sensitive to high temperature. The probable function of PSE(T) is discussed.     

Genotypic and environmental variation in cadmium, chromium, arsenic, nickel, and lead concentrations in rice grains

Genotypic and environmental variation in Cd, Cr, As, Ni and Pb concentrations of grains, and the relationships between these heavy metals and Fe, Zn were investigated using 9 rice genotypes grown in 6 locations for two successive years. Significant genotypic variation was detected in the five heavy metal concentrations in grains, indicating the possibility to reduce the concentration of these heavy metals in grains through breeding approach. The environmental effect varied with metal, with Pb and Ni having greater variation than the other three metals. There was significant genotype-environment （location） interaction of the concentrations of all five heavy metals in grains, suggesting the importance of cultivar choice in producing rice with low heavy metal concentrations in grains for a given location. Correlation analysis showed that Cd and As, Cr and Ni, and As and Pb concentrations in rice grains were closely associated, and that Ni concentration in grains was negatively correlated with Zn concentration.     

Molecular characterization of a defense-related AMP-binding protein gene, OsBIABP1, from rice

We cloned and characterized a rice gene OsBIABPI encoding an AMP-binding protein. The full-length cDNA of OsBIABP1 is 1912-bp long and is predicted to encode a 558-aa protein. OsBIABP1 contains a typical AMP-binding signature motif and shows high similarity to members of AMP-binding protein family. OsBIABP1 is expressed in stems, leaves and flowers of rice plants, but is not expressed, or expressed at a very low level, in rice roots. The expression of OsBIABP1 was induced by some defense-related signal molecules, e.g., salicylic acid (SA), benzothiadiazole, jasmonic acid (JA), and 1-amino cyclopropane-1-carboxylic acid, which mediate SA-and JA/ethylene (ET)-dependent defense signaling pathways, respectively. Furthermore, the expression of OsBIABP1 is activated by the infection of Magnaporthe oryzae, and the induced expression is quicker and stronger during early stages of pathogenesis in incompatible interaction than that in compatible interaction between rice and M. oryzae. Our results suggest that OsBIABP1 may be a defense-related AMP-binding protein that is involved in the regulation of defense re-sponse through SA and/or JA/ET signaling pathways.     

水稻微卫星标记的研究进展

微卫星又称简单重复序列,是一类由几个核苷酸(一般1～6个)为重复单元而形成的串联重复序列.由于它具有含量丰富、多态性高、共显性和检测方法简单等优点,而广泛应用于品种鉴定、种质资源保护、遗传作图、基因定位和QTL分析等方面.文章就微卫星标记在水稻中的开发和应用进展作一概述.     

水稻穗内不同粒位间的矿质营养变化差异及其与籽粒植酸含量的关系

研究目的：阐明水稻穗内不同粒位间的主要矿质营养元素和植酸含量差异、粒位分布特点及其与品种穗型间的联系。 创新要点：将水稻品种的穗型变化与稻米营养品质结合起来,从水稻穗粒结构角度,对同一稻穗内不同籽粒间的主要矿质营养元素与植酸含量差异、粒位分布特点及其与水稻品种穗型间的相互关系进行了较系统的探讨分析。 研究方法：以典型的直立穗型和弯穗型粳稻品种为材料,通过对两类水稻品种在相同栽培条件下籽粒矿质营养元素和植酸含量的测定分析,并依据水稻籽粒在稻穗上的着生部位,将同一稻穗内的不同籽粒划分为六个粒位,比较分析了两类品种同一稻穗内不同部位间矿质营养元素和植酸含量的差异变化及其粒位分布特点。 重要结论：水稻穗型虽然与品种问的籽粒矿质营养元素和植酸含量高低没有直接关系,但对其穗内不同籽粒间的主要矿质营养元素和植酸含量存在着较大影响;与稻穗中下部的弱势粒相比,同一稻穗内着生在稻穗上中部的强势粒通常具有相对较高的锌、铁矿质元素含量,而籽粒植酸含量和植酸,锌（铁）摩尔比则有所降低,稻米营养品质也相对较好;不同矿质营养元素相比,粒位效应对铁矿质营养的影响作用要略大于对钙和锌营养元素含量。     

水稻颖壳异常发育突变体Oryza sativa extraordinary glume 1 (Oseg 1) 的遗传与基因初定位分析

A rice mutant with Yaponica 9522 cultivar background Oryza sativa extraordinary glume 1 （Oseg 1） was identified from the M2 mutant pool mutagenized by ^60Co γ-ray. Compared with wild type plants, Oseg 1 developed longer empty glumes and rudimentary glumes. In some Oseg 1 mutants, the number of stamens of flowers was reduced and leaf-like lodicules occurred, and excessive lemma/palea-like organ could be observed in some mutant spikelets. This indicated that OsEG1 could regulate the development of rudimentary glumes, empty glumes, lemma/palea, lodicules, and stamens. Genetic analysis indicated that Oseg 1 came from a single recessive genetic locus. To clone OsEG1 gene, F2 population was constructed by a cross between Oseg 1 （Japonica） and Guangluai4 （Indica）. Using map-based cloning approach, OsEG1 was mapped on chromosome 4, between INDEL marker OS407 and WHM0466 with genetic distance of 2.0 cm and 1.0 cm, respectively. These results are useful for further cloning and functional analysis of the OsEG1 gene.     

Cloning and characterization of a glucose 6-phosphate/phosphate translocator from<Emphasis Type="Italic">Oryza sativa</Emphasis>

Plastids of nongreen tissues import carbon as a source of biosynthetic pathways and energy, and glucose 6-phosphate is the preferred hexose phosphate taken up by nongreen plastids. A cDNA clone encoding glucose 6-phosphate/phosphate translocator (GPT) was isolated from a cDNA library of immature seeds of rice and named asOsGPT. The cDNA has one uninterrupted open reading frame encoding a 42 kDa polypeptide possessing transit peptide consisting of 70 amino acid residues. TheOsGPT gene maps on chromosome 8 of rice and is linked to the quantitative trait locus for 1000-grain weight. The expression ofOsGPT is mainly restricted to heterotrophic tissues. These results suggest that glucose 6-phosphate imported viaGPT can be used for starch biosynthesis in rice nongreen plastids. Project supported by National Natural Scienc Foundation of China (No.39830250) and Natural Science Foundation of Zhejiang Province (No.2A0106), China. The nucleotide sequence data will appear in the GenBank under accession number AF375053.     

水稻颖壳异常发育突变体Oryza sativa extraordinary glume 1(Oseg 1)的遗传与基因初定位分析(英文)

A rice mutant with Japonica 9522 cultivar background Oryza sativa extraordinary glume 1 (Oseg 1) was identified from the M2 mutant pool mutagenized by ~(60)Coγ-ray.Compared with wild type plants,Ose9 1 developed longer empty glumes and rudimentary glumes.In some Oseg 1 mutants,the number of stamens of flowers was reduced and leaf-like lodicules occurred,and excessive lemma/palea-like organ could be observed in some mutant spikelets.This indicated that OsEG1 could regulate the development of rudimentary glumes,empty glumes,lemma/palea,lodicules,and stamens.Genetic analysis indicated that Oseg 1 came from a single recessive genetic locus.To clone OsEG1 gene,F_2 population was constructed by a cross between Ose9 1(Japonica)and Guangluai4(Indica).Using map-based cloning approach,OsEG1 was mapped on chromosome 4,between INDEL marker OS407 and WHM0466 with genetic distance of 2.0 cm and 1.0 cm,respectively.These results are useful for further cloning and functional analysis of the OsEG1 gene.     

Isolation and physiological characteristics of a premature senescence mutant in rice(Oryza sativa L.)

INTRODUCTION Leaf senescence is a kind of programmed cell death (PCD) in plants that is highly controlled by a genetically programmed process involving degrada-tion of cellular structures, decline of photosynthesis massive generation of active oxygen species (AOS) and mobilization of nutrients (Nam, 1997; Lim et al.,2003). Many environmental factors have been shown to play a role in causing the photosynthetic decline to lead to premature senescence. Leaves exposed to ultraviolet radia…     

信用证支付方式的收汇风险及其规避

信用证支付方式下的收汇风险主要由伪造信用证和"软条款"信用证引起,出口商防范外汇风险的措施包括:慎重选择贸易伙伴;提高业务人员素质;严格审证,认真备单,等等。