Splicing-site recognition of rice (Oryza sativa L.)DNA sequences by support vector machines

Motivation: It was found that high accuracy splicing-site recognition of rice (Oryza sativa L.) DNA sequence is especially difficult. We described a new method for the splicing-site recognition of rice DNA sequences. Method: Based on the intron in eukaryotic organisms conforming to the principle of GT-AG, we used support vector machines (SVM) to predict the splicing sites. By machine learning, we built a model and used it to test the effect of the test data set of true and pseudo splicing sites. Results: The prediction accuracy we obtained was 87.53% at the true 5' end splicing site and 87.37% at the true 3' end splicing sites. The results suggested that the SVM approach could achieve higher accuracy than the previous approaches.     

Splicing-site recognition of rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) DNA sequences by support vector machines

Motivation: It was found that high accuracy splicing-site recognition of rice (Oryza sativa L.) DNA sequence is especially difficult. We described a new method for the splicing-site recognition of rice DNA sequences. Method: Based on the intron in eukaryotic organisms conforming to the principle of GT-AG, we used support vector machines (SVM) to predict the splicing sites. By machine learning, we built a model and used it to test the effect of the test data set of true and pseudo splicing sites. Results: The prediction accuracy we obtained was 87.53% at the true 5′ end splicing site and 87.37% at the true 3′ end splicing sites. The results suggested that the SVM approach could achieve higher accuracy than the previous approaches. Project partially supported by the Start-up Funding of Zhejiang University to Chen Liang-biao     

A new genetic factor for root gravitropism in rice (Oryza sativa L.)

Root gravitropism is one of the important factors to determine root architecture. To understand the mechanism un-derlying root gravitropism, we isolated a rice (Xiushui63) mutant defective in root gravitropism, designated as glsl. Vertical sections of root caps revealed that glsl mutant displayed normal distribution of amyloplast in the columella cells compared with the wild type. The glsl mutant was less sensitive to 2,4-dichlorophenoxyacetic acid (2,4-D) and a-naphthaleneacetic acid (NAA) than the wild type. Genetic analysis indicated that the phenotype of glsl mutant was caused by a single recessive mutation, which is mapped in a 255-kb region between RM16253 and CAPSI on the short arm of chromosome 4.     

水稻RILs化感作用遗传模型分析

本研究以Lemont（弱化感）和Dular（强化感）水稻杂交产生的重组自交系（recombinent inbred lines,RILs）及其亲本为供体植物,并以稻田主要杂草稗草为受体植物,采用迟播共培法对群体及亲本化感作用进行测定及评价,应用主基因＋多基因分离分析法研究水稻化感作用的遗传体系。结果表明,水稻亲本化感抑草作用差异较大,对受体稗草的根长抑制率呈连续变异,体现出数量性状特征;水稻Lemont（弱化感）×Dular（强化感）组合的Rlhs群体化感作用遗传体系由两对连锁的主基因控制,主基因间的作用方式呈互补作用。进一步估计受体根长抑制率的遗传参数,结果表明,稗草根长抑制率的群体均值m=29．3908245,主基因加性效应与加性×加性上位性互作效应I^＊=7．0619195,主基因遗传率为49．36379％．     

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.     

Production of bacterial blight resistant lines from somatic hybridization between Oryza sativa L.and Oryza meyeriana L.

Novel bacterial blight (BB) resistance gene(s) for rice was (were) introduced into a cultivated japonica rice variety Oryza sativa (cv. 8411), via somatic hybridization using the wild rice Oryza meyeriana as the donor of the resistance gene(s). Twenty-nine progenies of somatically hybridized plants were obtained. Seven somatically hybridized plants and their parents were used for AFLP (amplified fragment length polymorphism) analysis using 8 primer pairs. Results confirmed that these plants were somatic hybrids containing the characteristic bands of both parents. The morphology of the regenerated rice showed characters of both O. sativa and O. meyeriana. Two somatic hybrids showed highest BB resistance and the other 8 plants showed moderate resistance. The new germplasms with highest resistance have been used in the rice bfeeding program for the improvement of bacterial blight resistance.     

Production of bacterial blight resistant lines from somatic hybridization between Oryza sativa L. and Oryza meyeriana L.

Novel bacterial blight (BB) resistance gene(s) for rice was (were) introduced into a cultivated japonica rice variety Oryza sativa (cv. 8411), via somatic hybridization using the wild rice Oryza meyeriana as the donor of the resistance gene(s). Twenty-nine progenies of somatically hybridized plants were obtained. Seven somatically hybridized plants and their parents were used for AFLP (amplified fragment length polymorphism) analysis using 8 primer pairs. Results confirmed that these plants were somatic hybrids containing the characteristic bands of both parents. The morphology of the regenerated rice showed characters of both O. sativa and O. meyeriana. Two somatic hybrids showed highest BB resistance and the other 8 plants showed moderate resistance. The new germplasms with highest resistance have been used in the rice breeding program for the improvement of bacterial blight resistance.     

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…     

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.     

Genetic basis of heterosis and inbreeding depression in rice (Oryza sativa L.)

The genetic basis of heterosis was studied through mid-parent, standard variety and better parent for 11 quantitative traits in 17 parental lines and their 10 selected hybrids in rice (Oryza sativa L.). The characters were plant height, days to flag leaf initiation, days to first panicle initiation, days to 100% flowering, panicle length, flag leaf length, days to maturity, number of fertile spikelet/panicle, number of effective tillers/hill, grain yield/10-hill, and 1000-grain weight. In general the hybrids performed significantly better than the respective parents. Significant heterosis was observed for most of the studied characters. Among the 10 hybrids, four hybrids viz., 17A×45R, 25A×37R, 27A×39R, 31A×47R, and 35A×47R showed highest heterosis in 10-hill grain yield/10-hill. Inbreeding depression of F2 progeny was also studied for 11 characters of 10 hybrids. Both positive and negative inbreeding depression were found in many crosses for the studied characters, but none was found significant. Selection of good parents was found to be the most important for developing high yielding hybrid rice varieties.     

Genetic basis of heterosis and inbreeding depression in rice (Oryza sativa L.)

INTRODUCTIONAlthoughriceisanaturallyself-pollinatedcrop,strongheterosisisobservedintheirF1hybrids.HeterosisorhybridvigorismanifestedasimprovedperformanceforF1hybridsgeneratedbycrossingtwoinbredparents.Heterosiscanbedefinedquan-titativelyasanupwarddeviationofthemid-parent,basedonthemeanvaluesofthetwoparents(JohnsonandHutchinson,1993).Heterosismaybepositiveornegative.Dependinguponbreedingob-jectives,bothpositiveandnegativeheterosisareusefulforcropimprovement.Ingeneral,positiveheterosisisd…     

Production of bacterial blight resistant lines from somatic hybridization between Oryza sativa L. and Oryza meyeriana L.

Novel bacterial blight (BB) resistance gene(s) for rice was (were) introduced into a cultivated japonica rice variety Oryza sativa (cv. 8411), via somatic hybridization using the wild rice Oryza meyeriana as the donor of the resistance gene(s). Twenty-nine progenies of somatically hybridized plants were obtained. Seven somatically hybridized plants and their parents were used for AFLP (amplified fragment length polymorphism) analysis using 8 primer pairs. Results confirmed that these plants were somatic hybrids containing the characteristic bands of both parents. The morphology of the regenerated rice showed characters of both O. sativa and O. meyeriana. Two somatic hybrids showed highest BB resistance and the other 8 plants showed moderate resistance. The new germplasms with highest resistance have been used in the rice breeding program for the improvement of bacterial blight resistance. Project (No. 98001) supported by Ningbo Agriculture Key Scientific Research Foundation, China     

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.     

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.     

属间远缘杂交水稻耐铁毒性研究

以吉田昌—培养液为对照，添加不同浓度ＦｅＳＯ４作为铁毒胁迫处理，对二个属间远缘杂交水稻“远诱１号”和“遗传工程水稻１号”及三系杂交组合“汕优６３”二叶龄幼苗进行耐铁毒性比较鉴定．试验结果表明，３个试验材料的耐铁毒性以高粱稻远诱１号及三系稻汕优６３较强，遗传工程水稻１号耐铁毒性相对较弱．根据溶液中Ｆｅ２＋／Ｆｅ３＋的变化规律，稻体内持铁量的差异，稻株根系氧化力的区别，拒斥可能是汕优６３的耐铁毒性生理基础，遗传工程水稻１号的耐性机制为容耐，而远诱１号的耐铁生理基础兼具拒斥与氧化双重机制而偏倚于主动氧化机制．体内钾、硅、镁、钙含量与铁离子含量密切相关，丰富的钾、硅、镁可以改善水稻的耐铁毒性     

免耕水稻的营养生理性状与谷产量(英文)

用早熟籼稻“陆青早1号”和中熟杂交稻“威优64”,直接播种于盛有2年免耕土壤的塑料盆(70×45×20cm)与常规耕作为对照,3次重复。试验结果表明,“威优64”和“陆青早1号”根吸收 ~(32)P和分配到各个生育期生长中心多,尤以抽穗期和成熟期分配到稻穗的量比对照的多。~(14)C —葡萄糖同化物从涂叶的输出率(％)、总氮和可溶性蛋白质含量、总糖和可溶性糖含量在各个生育期均比对照的高。免耕稻两个品种乳熟期和成熟期茎的干物重增重,由乳熟期至成熟期茎秆物质运转率高,成熟期茎鞘总糖向谷粒运转率也高,成熟期叶片、叶鞘和稻穗干物重比常规耕作的增重,茎秆比较轻,运转和给稻穗贡献率高,两个免耕稻种的谷粒产量结构比对照良好,第一次枝梗数,第二次枝梗数,每穗总粒,每穗充实粒,结实率,1000粒重,茎/秆比,经济系数比常规耕作的高,谷粒产量增加。本文还证明在免耕条件下杂交稻“威优64”植株性状和营养生理性状比“陆青早1号”良好,具有明显的杂种优势。     

水杨酸对NaCl胁迫下水稻(Oryza Saliva L.)幼苗生理活性的影响

用0．2％水杨酸处理1．2％NaCl胁迫下水稻种子，测定其以下几个生理指标，种子的发芽率，发芽势和幼苗中的酯酶，过氧化氢酶以及抗坏血酸的含量，实验结果显示：外源性水杨酸能够相对提高NaCl胁迫下水稻种子萌发后幼苗的过氧化物酶活性和抗坏血酸的含量，同时也能提高水稻种子的发芽率，发芽势，但对酯酶活性影响不大，研究表明水杨酸能提高水稻种子萌发后幼苗的抗盐性，并使水稻种子出苗整齐，一致。     

光敏核不育水稻花粉形态和育性稳定性及转换

对HPGMR农垦58A进行育性转换的稳定性研究,用扫描电镜观察其花粉外部形态。结果表明,长日诱导的值株及短日割蔸再生分蘖,在长日下均表现雄性不育,结实率分别为0.76％和0.00％;短日诱导及对照组植株雄性可育,结实率分别为40.59％和38.19％;长日诱导的花粉外形明显皱缩,不含内容物,属典败型花粉;而短日诱导的花粉除极少量皱折外,大多呈圆型而充实,内容物饱满。     

Genetic basis of heterosis and inbreeding depression in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

The genetic basis of heterosis was studied through mid-parent, standard variety and better parent for 11 quantitative traits in 17 parental lines and their 10 selected hybrids in rice (Oryza sativa L.). The characters were plant height. days to flag leaf initiation, days to first panicle initiation, days to 100% flowering, panicle length, flag leaf length. days to maturity, number of fertile spikelet/panicle, number of effective tillers/hill, grain yield/10-hill, and 1000-grain weight. In general the hybrids performed significantly better than the respective parents. Significant heterosis was observed for most of the studied characters. Among the 10 hybrids, four hybrids viz., 17A×45R, 25A×37R, 27A×39R, 31A×47R, and 35A×47R showed highest heterosis in 10-hill grain yield/10-hill. Inbreeding depression of F₂ progeny was also studied for 11 characters of 10 hybrids. Both positive and negative inbreeding depression were found in many crosses for the studied characters, but none was found significant. Selection of good parents was found to be the most important for developing high yielding hybrid rice varieties. Project supported by the Foundation of Ministry of Science and Information and Communication Technology, People's Republic of Bangladesh     

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.