Transgenic rice homozygous lines expressing GNA showed enhanced resistance to rice brown planthopper

Mature seed-derived calli from two elite Chinese japonica rice (Oryza sativa L.) cultivars Eyi 105 and Ewan 5 were co-transformed with two plasmids, pWRG1515 and pRSSGNA1, containing the selectable marker hygromycin phosphotransferase gene (hpt), the reporter β-glucuronidase gene (gusA) and the snowdrop (Galanthus nivalis) lectin gene (gna) via particle bombardment. 61 independent transgenic rice plants were regenerated from 329 bombarded calli. 79% transgenic plants contained all the three genes, revealed by PCR/Southern blot analysis. Western blot analysis revealed that 36 out of 48 gna-containing transgenic plants expressed GNA (75%) at various levels with the highest expression being approximately 0.5% of total soluble protein. Genetic analysis confirmed Mendelian segregation of transgenes in progeny. From the R2 generations whose R1 parent plants showing 3:1 Mendelian segregation patterns, we identified five independent homozygous lines containing and expressing all the three transgenes. Insect bioassay and feeding tests showed that these homozygous lines had significant inhibition to rice brown planthopper (Nilaparvata lugens, BPH) by decreasing BPH survival and overall fecundity, retarding BPH development and declining BPH feeding. These BPH-resistant lines have been incorporated into rice insect resistance breeding program. This is the first report that homozygous transgenic rice lines expressing GNA, developed by genetic transformation and through genetic analysis-based selection, conferred enhanced resistance to BPH, one of the most damaging insect pests in rice.     

稻属基因组间相关性的AFLP分析

应用AFLP（amplified restriction fragment length polymorphism)－银染法对2种栽培稻和21种野生稻的基因组多态性进行了检测,共计使用了9对选择性引物组合,扩增出602个遗传位点,通过Jacard的方法将电泳带矩阵转化为遗传相似性系数矩阵,并进行了聚类分析和主成分分析,结果表明,稻属植物按其亲缘关系的远近被分为三个大的类群：O.sativa群,O.officinalis群和其它远缘混合群,本文还对两种栽培稻的起源途径以及稻属物种的不同类型基因组间的缘关系进行了初步的探讨,为深入研究稻属物种间的进化关系提供参考。     

一种简单方法提高原生质体再生植株频率

发展了一种简单有效的方法,提高从灿稻品种Ｐｕｓａ Ｂａｓｍａｔｉ１建立的超过１年龄悬浮细胞系中游离的原生质体再生植株频率。两步再生法,即先将愈伤组织转入含高浓度琼脂糖（１０ｇ／Ｌ）的再生培养基中培养后再转入含低浓度琼脂糖（４ｇ／Ｌ）的再生培养基中培养,有助于植株再生,两步再生法结合使用含高浓度激动素Ｋｉｎｅｔｉｎ（１０ｍｇ／Ｌ）的再生培养基,显著提高植株再生频率,利用此法,可使来源于超过１年龄的悬     

籼粳杂交稻米品质性状与农艺性状之间的遗传协方差分析

用２个籼型水稻光温敏核不育系和７个粳型广亲和品种为材料，按ＮＣⅡ设计配制杂交组合，获得亲本、Ｆ１及Ｆ２代的籽粒群体，对８个主要品质性状和６个农艺性状进行测定，按混合线性模型的分析方法对品质性状与农艺性状之间的遗传协方差进行了研究，结果表明：在籼粳亚种间杂交组合中，稻米理化品质性状与植株农艺性状之间的遗传协方差大都为直接加性／母体加性协方差，外观品质性状与农艺性状之间的遗传协方差则主要是直接加性／母体加性协方差和母体加性／母体加性协方差，细胞质效应协方差也普遍存在．     

水稻OsICK1基因克隆及其序列分析

细胞周期蛋白依赖性激酶抑制剂（ICK）是一种能够影响细胞生长和发育的重要调控蛋白．以水稻（9311）为材料，利用RT-PCR技术，扩增获得了1个新的可能为水稻细胞周期蛋白依赖性激酶抑制剂的基因，命名为OsICK1．核苷酸序列分析表明，该基因的开放阅读框为585bp，编码194个氨基酸．与Genbank中预测的水稻ICK基因序列（NM_196964）比对，两者同源性为79．84％；氨基酸序列分析表明，该基因氨基酸序列3＇端附近存在植物ICK所固有的保守序列，与玉米ICK1保守序列的同源性高达95．5％．     

Isolation and characterization of rice lesion mimic mutants from a T-DNA tagged population

A rice ( Oryza sativa L. ssp. japonica cv. Nipponbare) T-DNA tagged population consisting of about 7000 individual lines was generated and screened for rice lesion mimic mutants in the T1 generation. Ten lines were found to develop spontaneous lesions in the absence of pathogen infection and displayed distinct lesion phenotypes. These mutants were tentatively designated as lm1 -lm10 (for lesion mimic), respectively. Lesion formation of lm mutants was developmentally regulated, and all the mutants showed stunted growth and reduced fertility. Genetic analysis demonstrated that all the mutations were recessive, and five partially fertile mutants (lm4-lm8) were derived from different loci. Mimic lesions occurring on the leaves of lm mutants resulted from cell death as revealed by trypan blue staining. Six of them ( lm3 -lm8 ) exhibited enhanced resistance to five bacterial blight isolates, indicating their wide-spectrum resistance to this pathogen. These results imply that some lesion mimic mutations of rice might be involved in disease resistance signaling pathways,and that isolation of these mutated genes may be useful for elucidating molecular mechanisms of plant disease resistance. Among the mutants, only one mutant, lm6, was preliminarily shown to cosegregate with the inserted T-DNA in its T1 generation, making it feasible to isolate the gene responsible for the phenotype of this mutant.     

Extension of the rice DH population genetic map with microsatellite markers

Genetic mapping of microsatellite markers was carried out in a rice DH population derived from across between Zaiyeqing 8 (indica) and Jingxi 17 (japonica). A total of 89 microsatellite markers, including 84 (GA)_n, 2(TCT)_n, 2(ATT)_n, and, l(ATC)_n motifs, were integrated relatively evenly into the established genetic map of the DH population. This will facilitate the utilization of microsatillite markers in rice gene mapping and marker aided breeding.     

Isolation of candidateR disease resistance genes from rice

Using a polymerase chain reaction (PCR) based method six distinct candidate disease resistant gene (R) homologs from rice have been isolated. The rice sequences are organized into two phylogenetic groups with contrasting genomic organization patterns. The first group, represented by a single sequence, Osh359-1, is more similar to non-riceR sequences than to rice ones and has a simple genomic organization. The second group, represented by Osh359-3, contains the remaining five rice sequences. Osh359-3 consists of a multi-gene family. The members of Osh359-3 family are further found to be clustered together in the genome.     

Diversity and high nitrogenase activity of endophytic diazotrophs isolated from Oryza rufipogon Griff.

Diversity and nitrogenase activity of endophytic diazotrophs colonized in the wild rice Oryza rufipogon Griff grown in Boluo, Huilai County in Guangdong Province and Lingshui County in Hainan Province were studied. Thirty-seven isolates obtained from Oryza rufipogon were identified as putative endophytic nitrogen-fixing bacteria by ARA （acetylene reduction assay） test and further confirmed by PCR amplification of nifH gene fragments. All obtained strains have ARA activity and the same sized nifH gene fragments. Above the similarity level of 80%, the obtained isolates were assigned as Group Ⅰ to Ⅷ by the clustering of IS-PCR fingerprints. The SDS-PAGE whole-cell protein patterns were similar to those of IS-PCR fingerprints. Components and contents of fatty acid methyl esters （FAMEs） were used to differentiate the representative strains （Ls13, Ls8, BL1, BL12, HL6, Ls4） from Group Ⅰ to Group Ⅵ. The six representative strains showed significant difference in contents and components of cellular fatty acid methyl ester. 16S rDNA sequencing analysis showed that strains of Group Ⅰ to Ⅶ were located in Enterobacteraceae （y-proteobacteria）. Strains of Group Ⅰ and Group Ⅱ were closely related to Klebsiella sp.; Strain Ls8 of Group Ⅱ was a little far away from the genus of Pantoea （homology level 96% with Pantoea agglomerans）, which may represent a new species or genus in Enterobacteraceae; Strains of Groups Ⅳ and Ⅴ belonged to different Enterobacter sp.; Strain Ls4 and Ls 9 representing Group Ⅵ were close to Citrobacter amalonaticus with 98% sequence similarity; Strain Ls15 of Group Ⅶ showed 98% sequence identity with Pantoea sp.; Strains of Group Ⅷ were assigned to the genus Ideonella （β-proteobacteria）. Based on the above results, endophytic diazotrophs isolated from O. rufipogon showed great diversity and some diazotrophs showed high nitrogenase activity with 42.52 μmol/mL. h C2H4. Inoculation to rice tests indicated that the isolated endophytic diazotrophs significantly promoted the rice growth.