Mitochondrial DNA variation in foxtail millet, Setaria italica (L.) P. Beauv.

Mitochondrial DNA (mtDNA) wascharacterized by RFLPs in 94 strains offoxtail millet, Setaria italica (L.)P. Beauv. Three RFLP patterns wereobserved by using rice atp6 as aprobe, and were designated as types I-III. Difference between types I and II seems tobe attributed to recombination between twoatp6 genes. In East and SoutheastAsia and Afghanistan, both of types I andII were found, while type I was predominantin India, Central Asia and Europe. InChina, type III was also found. Chinesestrains showed higher gene diversity thanthose from other regions. This resultcoincided the previous studies on isozymesand nuclear RFLPs.     

Inheritance of sethoxydim resistance in foxtail millet, Setaria italica (L.) Beauv.

Interspecific hybridization between foxtail millet cultivars (Setaria italica) and a green foxtail (S. viridis) resistant to the herbicide sethoxydim were undertaken to breed foxtail millet for improved herbicide resistance. Parents, reciprocal F₁ hybrids, F₂ selfed derived populations and BC₁ backcross progeny were produced and analysed for mortality and fresh weight over a range of dosages. All resistant progeny were 700 times more resistant than susceptible cultivars and was symptom free under current field dosages. Segregations of resistant and susceptible progeny (3:1 in F₂ and 1:1 in BC₁) were not dependent upon dosage. Heterozygous individuals displayed the same magnitude of resistance as homozygous plants at twelve times the recommended field dosage. Results suggested that sethoxydim resistance in foxtail millet was controlled by a single, completely dominant, nuclear gene. This revised version was published online in July 2006 with corrections to the Cover Date.     

Development and utilization of novel SSRs in foxtail millet [Setaria italica (L.) P. Beauv.]

Although the foxtail millet [Setaria italica (L.) P. Beauv.] is recently regarded as a model crop for studying functional genomics of biofuel grasses, its genetic improvement to some extent was limited due to the non‐availability of molecular markers, particularly the microsatellite markers and the saturated genetic linkage map. Considering this, we attempted to generate a significant number of microsatellite markers in cultivar ‘Prasad’. Two hundred and fifty‐six clones were sequenced to generate 41.82‐kb high‐quality sequences retrieved from genomic library enriched with dinucleotide repeat motifs. Microsatellites were identified in 194 (76%) of the 256 positive clones, and 64 primer pairs (pp) were successfully designed from 95 (49%) unique SSR‐containing clones. The 67.4% primer designing ability, 100% PCR amplification efficiency and 45.3% polymorphic potential in the parents of F₂ mapping population established the efficacy of genomic microsatellites. All the 64 microsatellite markers displayed high level of cross‐species amplification (~67%) in 10 millets and non‐millets species. These experimental findings suggest the utility and efficacy of SSRs in diverse genotyping applications, resolving QTLs, phylogenetic relationships and transferability in several important grass species.     

Traditional maintenance and multiplication of foxtail millet (Setaria italica (L.) P. Beauv.) landraces in China

Summary Foxtail millet (Setaria italica L. P. Beauv.) has been one of the most important cereals in northern China. A large number of landraces have formed under natural and man-made selection since domestication. Farmers in China have developed various traditional methods of maintenance and multiplication of foxtail millet seeds for next generation. Panicle selection was often done in fields. The selected seeds were generally stored at dry places. Archaeological and historical evidence of the origin of foxtail millet in China and the geographical distribution of landraces is also presented.     

Indentification of true genetic dwarfing sources in foxtail millet (Setaria italica Beauv.)

Summary True genetic dwarfs hither-to not reported have been located in foxtail millet. The dwarfs as a group distinguished themselves from the talls in having altered constellation of characters. The morphological differences were highly significant for plant height, internodal length, and tillering potential. The talls had elongated internodes compared to dwarfs while there was no difference for node number on the main stem suggesting that short internodal length was primarily responsible for dwarfism. The dwarfs also showed slightly higher leaf number per plant, leaf area and harvest index compared to talls. The dwarfs were insensitive to exogenous GA₃ application indicating that GA₃ synthesis is not impaired. This suggests that dwarfing gene sources presently identified are true genetic dwarfs and their behaviour is similar to dwarfs derived from Norin 10 in wheat and Dee-geo-woo-gen in rice. The superior morphological frame makes these dwarfs ideal as far as plant type is concerned and offers immense potentialities in breeding high yielding foxtail millets.     

Breeding strategy in foxtail millet,Setaria italica (L.P. Beauv.), following interspecific hybridization

Summary An interspecific cross between foxtail millet Setaria italica and its wild relative Setaria viridis was undertaken in order to introduce from the latter triazine resistance in the cultivated plant. Four backcross generations obtained with S. italica as recurrent parent were studied. Results show that only two backcross generations associated with selection are enough to eliminate weedy characters and to return to the cultivated type. S. viridis could thus be an interesting source for improvement of foxtail millet without a complex and time consuming breeding strategy.     

Genetic variability in foxtail millet, Setaria italica (L.) P. Beauv. - RFLP using a heterologous rDNA probe

Ribosomal DNA was surveyed in a world collection (43 lines) of Setaria italica for variation in repeat unit length and restriction enzyme site variability using a non-radioactive wheat rDNA probe. Only two lengths of repeat units of about 7.9 or 7.6 kb were observed. The fact that these two repeat unit lengths were not randomly dispersed throughout the world collection suggests the existence of three genetic groups. The central European lines and most western European accessions have only the 7.6 kb repeat unit and most Asiatic lines have a 7.9 kb repeat unit. Lines originating from the north or the south of Asia showed different numbers of Bam HI fragments. The fact that the difference between the Asiatic and European pool is not continuous (7.9 or 7.6 kb) excludes the hypothesis of domestication being based on the spread of an initial population over Eurasia.     

Genetic variability in foxtail millet, Setaria italica (L.) P. Beauv.: Identification and classification of lines with RAPD markers

The DNA of 37 lines of Setaria italica, representative of Eurasian diversity, were used for the detection of polymorphism using the random amplified polymorphic DNA (RAPD) method. Four 10-mer primers, differing from each other by one or two G-C inversions, were used. Each one gave specific RAPD products. Twenty-five bands were polymorphic and allowed the identification of 33 different genotypes. A factorial analysis of correspondence was performed on the presenc-absence data, through which three genetic groups could be identified. These genetic groups were closely related to the geographical origin of the different lines: one central European and two Asiatic groups (the first Asiatic lines originating in latitudes below 35°N and the second comprising the Asiatic lines originating in latitudes above 35° N). The lines originating from western Europe were very variable and were dispersed in the three genetic groups described previously.     

谷子叶绿体基因RNA编辑位点的鉴定与分析

RNA编辑是高等植物叶绿体基因转录后加工修饰的现象,它会影响叶绿体发育,导致植株叶片出现黄化或白化等表型。本研究以长农35号及其2份叶色突变体(E752和E1005)为试验材料,利用紫外分光光度计测定了苗期叶绿素含量,通过透射电镜观察了叶绿体结构;利用在线工具Prep-Cp对谷子叶绿体基因RNA编辑位点进行了预测,通过PCR、RT-PCR及测序等方法对预测到的编辑位点进行了验证,并与其他单子叶作物的编辑位点进行了比较分析;进一步利用荧光实时定量方法,分析rpoB及依赖PEP转录的光合途径相关基因(ndhG、psaA、psbA和rbcL)在不同发育时期的表达水平;最后,利用生物信息学分析ropB编辑前后蛋白二级结构的变化。结果表明,与长农35号相比,2份叶色突变体叶绿素含量显著降低,叶绿体发育异常;在谷子中,有10个叶绿体基因共计20个位点发生RNA编辑,所有编辑位点均为胞嘧啶(C)和尿嘧啶(U)的转换,不同基因的编辑位点存在数量差异,其中ndhB编辑位点数量最多,共计6个; 20个编辑位点中,有19个位点在物种进化上具有较高保守性,只有rpoC1-2753为谷子中特有的编辑位点;在长农...     

Effects of the two most common Wx alleles on different genetic backgrounds in rice

Wx^a and Wx^b are the most common alleles of the Wx gene in Asian cultivated rice. The difference between them is responsible for differences in the levels of the Wx gene product in the endosperm, as well as in amylose content, which is an important determinant of the quality of edible rice. Since Indica rice mostly carries the Wx^a allele, we introduced the Wx^b allele into Indica‐type rice (IR36) from a Japonica‐type rice (T65) by repeated backcrossing. In the near‐isogenic line (IR36 Wx^b), the level of the Wx gene product was reduced and, as expected, the level of amylose. However, IR36Wx^b had a lower amylose content than the recurrent parent of T65 with the Wx^b allele. The results suggest that the Indica (IR36) background might lower the amylose content more than the Japonica (T65) background when the Wx allele is the same. The possible importance of modifiers that regulate expression of the Wx gene is also discussed in relation to improvements in the grain quality of rice.     

Gene dosage effect of the wheat Wx alleles and their interaction on amylose synthesis in the endosperm

To find out gene dose effect of each of the three homoeologous Wx genes and their interaction on the production of granule-bound starch synthase (GBSS I) and amylose biosynthesis in the endosperm, Chinese Spring and its near-isogenic waxy types were crossed reciprocally and, obtained a plant population with varying doses of each Wx gene. The amount of GBSSI was increased linearly with increasing gene dose of either of Wxloci. In each of the three Wx loci, the change in amylose content was linear up to 3 doses, with a more potent capacity ofWx-B1a at any dose. Higher level of amylose production was observed in the reciprocal F₁ grains than the expected effect of dose/s of each gene or additive effect of different allelic combination by artificially blend starches which have amylose produced by equivalent number ofWx alleles to that of relevant F₁ cross. When Wx-B1a and Wx-A1a were combined, increase in amylase content was not in proportion to increase in gene dosage. The enhanced amylase synthesis was shown by 2-gene and 3-geneinteraction, indicating that not only type of the three Wx genes and its dose but the interaction among them have significant roles in determining the amylose content. This revised version was published online in July 2006 with corrections to the Cover Date.     

Decrease of Waxy (Wx) Protein in Two Common Wheat Cultivars with Low Amylose Content

Two cultivars with a low amylose content, Kanto107 (K107) and K79, were discovered in Japanese common wheat (Triticum aestivum L.). The amount of Wx protein, identified as a single major starch granule-bound protein of about 61 kD by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), was greatly decreased in those two cultivars. Analysis of their Wx protein with a modified SDS-PAGE and two dimensional-PAGE showed that two of the three Wx proteins, produced by Wx-A1 and Wx-B1 loci, were not detected. It was thus concluded that only one locus, Wx-D1, was active in the two low amylose cultivars. These mutants were termed “partial waxy mutants” and considered to be very useful material for breeding waxy wheat.     

不同光温条件谷子光温互作模式研究及SiCCT基因表达分析

光周期和温度是影响作物生长发育、生态适应性和产量的2个重要环境因素,揭示光温互作对作物生长发育的效应及其分子机制对育种实践和理论研究具有重要意义。本研究设置长日照高温、长日照低温、短日照高温、短日照低温4个光温处理,调查‘黄毛谷’抽穗期、株高、叶片数和穗长。结果表明,光周期对谷子的发育起关键作用,温度的改变不影响长日照比短日照延迟谷子生殖生长的效应,温度的作用随光周期的不同而异,短日照条件下,高温缩短谷子营养生长期而低温延长营养生长期,长日照条件下则相反;对谷子生殖生长的促迚作用是短日照高温>短日照低温>长日照低温>长日照高温。利用RT-PCR技术从‘黄毛谷’叶片兊隆了一个CCT结构域基因(SiCCT),该基因编码286个氨基酸,属于CMF亚家族成员,基于CCT域基因氨基酸序列的系统迚化分析,谷子与高粱、玉米亲缘关系较近。实时荧光定量PCR分析发现, SiCCT基因在‘黄毛谷’叶片中高表达,其次为幼穗和叶鞘;长日照、短日照处理SiCCT基因均表现24h昼夜节律性特点,短日照七叶期表达水平最高,八叶期(抽穗)及穗后表达迅速降低,长日照七叶至十叶期‘黄毛谷’处于营养生长期...     

谷子抗除草剂“拿捕净”基因的AFLP标记

对由一对显性核基因(Srf)控制的谷子抗除草剂拿捕净(Sethoxydim)种质抗性进行了分子标记的研究.通过采用F2代群分法,在谷子F2代抗感池间随机筛选了330对AFLP引物,找到了与谷子抗除草剂基因连锁的两个AFLP标记AP1284(M55/15)和AP2350(M55/14).它们位于抗除草剂基因的一侧,与该基因的遗传图距分别为6.3 cM和2.9 cM.二者间的遗传     

谷子干草饲用品质性状变异及相关性分析

谷子是重要的饲草作物, 但其饲草品质性状研究滞后制约了谷子饲草品种培育和栽培。本研究对47个谷子品种在我国高寒农牧地区栽培的饲用干草品质性状进行了系统测定。结果表明, 供试材料粗蛋白含量的变异范围为5.42%~12.45%, 变异系数为14.25;粗脂肪含量的变异范围为0.64%~1.43%, 变异系数为15.84;粗灰分含量的变异范围为8.50%~15.60%, 变异系数为13.71;总磷含量的变异范围为0.10%~0.32%, 变异系数为20.00;总钙含量的变异范围为0.27%~0.67%, 变异系数为20.00。粗纤维、无氮浸出物和水分含量表现出较小的变异。主成分分析表明, 影响谷子饲草品质的主要性状是粗纤维、粗灰分、粗蛋白和无氮浸出物, 粗蛋白与粗纤维和无氮浸出物均为负相关。综合表明, Li05-569、饿死驴、系295和红根谷是品质性状综合表现优良的品种。     

Inheritance of amylose content in rice (Oryza sativa L.)

Summary The inheritance of low and very low amylose contents in six rice crosses and their reciprocals was studied by single grain analysis of parents F₁, F₂, B₁ and B₂ seeds. To minimize the environmental effects, the seeds of all generations of all crosses were produced in a single season. The results indicated different dosage effects in different crosses. One major gene was found to govern a difference of 6–12% in amylose content in low and intermediate amylose parents. Very low amylose content was similarly found to be governed by one major gene in crosses between very low- and low-amylose content parents. Minor genes and modifiers also seem to play some role. In the cross between two low amylose parents differing by about 2.5% in amylose content, the differences appeared to be controlled by some minor genes and modifiers. The selection program in different crosses has been suggested.     

利用A-PAGE研究谷子籽粒蛋白质多态性

研究谷子贮藏蛋白多态性对谷子品种选育和鉴定评价具有重要的意义。本文利用A-PAGE方法对来自不同生态区的24份谷子品种籽粒的水溶蛋白、盐溶蛋白、酸溶蛋白和醇溶蛋白的多态性进行了研究。结果发现,不同谷子品种之间籽粒水溶蛋白、酸溶蛋白谱带相似,基本没有差异;每个谷子品种的盐溶蛋白谱带有20多条,仅有4个品种出现多态性谱带,多态性也较低。说明谷子品种水溶蛋白、盐溶蛋白和酸溶蛋白A-PAGE谱带不适用于谷子鉴定研究。谷子醇溶蛋白谱带存在一定的异质性,每个品种有7~10条醇溶蛋白谱带,其中5条为公共条带,2~5条为多态性谱带,醇溶蛋白A-PAGE谱带可以作为谷子品种鉴定评价的依据。结果说明,和玉米、小麦等禾谷类作物相比,不同生态区谷子栽培品种蛋白质变异较小,遗传背景变化较小,因此需要不断丰富谷子品种的遗传基础,为谷子品种选育提供更加丰富的材料。     

Novel Wx alleles induced by chemical mutagens in rice,Oryza sativa L.

From mutant pools of two Taiwanese elite japonica cultivars, Tainung 67 and Taikeng 8, we identified 13 mutant lines possessing opaque endosperm with relatively low amylose contents (AC) ranging from 1.5% to 7.1%. Because of different AC, paste viscosities of these 13 mutant lines differed, as revealed by palatability and physicochemical properties. The mutated gene conferring opaque endosperm was isolated from the F₂ population of one mutant line, WY1× indica cv. ‘Taichung Sen 17’, by positional cloning, revealing a G3018→A3018 substitution at exon 9 of Waxy leading to a non‐synonymous mutation from alanine to valine. Two additional alleles were identified from the other 12 mutant lines, for which single‐nucleotide substitutions G2708 → A2708 and G3029 → A3029 occurred in exons 8 and 9, leading to non‐synonymous mutations from arginine to histidine and glutamic acid to lysine, respectively. The three novel wx alleles had different effects on grain quality, specifically on eating and cooking quality, and could be applied in rice breeding programmes to develop new low AC varieties by marker‐assisted selection.     

谷子SiPRR37基因对光温、非生物胁迫的响应特点及其有利等位变异鉴定

从谷子品种延谷11号克隆生物钟基因SiPRR37,通过生物信息学分析、组织特异性表达分析、4种不同光温组合条件的昼夜表达模式分析以及对NaCl、ABA、PEG、低温、Fe 5种非生物胁迫的响应特点分析,揭示SiPRR37参与谷子光温互作调控以及应对非生物胁迫的作用机制;并对160份谷子材料重测序检测SiPRR37基因的突变位点进行单倍型分析,探究该基因对谷子主要农艺性状的影响。结果表明,SiPRR37基因蛋白质编码区(sequence coding for amino acids in protein,CDS)全长2247 bp,编码748个氨基酸,含有REC和CCT 2个结构域,基于PRR37蛋白的系统进化分析发现,谷子与糜子、高粱、玉米亲缘关系最近;启动子预测分析发现,SiPRR37启动子区存在光、温、生长素、赤霉素、脱落酸、茉莉酸甲酯、干旱和盐胁迫等多种应答元件。SiPRR37相对表达量从高到低依次为根、穗颈、穗、顶叶、次顶叶、茎秆;4个光温组合条件SiPRR37均只在光照期出现1个表达峰,无论高温(27℃)还是低温(22℃),短日照相比长日照表达峰均要提前,无论长日照还是短日照,低温(22℃)相比高温(27℃)表达峰均要提前;NaCl、低温(15℃)胁迫能够抑制SiPRR37表达,PEG模拟干旱胁迫和Fe胁迫能够诱导SiPRR37基因表达,SiPRR37参与了ABA信号传导过程。位于SiPRR37 CDS区的10个SNP将160份谷子材料分为19个单倍型,其中3个单倍型(Hap_7、Hap_10、Hap_19)是改善穗部性状的有利单倍型。谷子SiPRR37基因表达具有昼夜节律性,同时受光周期和温度调控,并且参与了谷子对盐胁迫、低温胁迫、干旱胁迫和铁胁迫的应答反应,同时SiPRR37与抽穗期和多个穗部性状相关,在开展谷子高产分子辅助选育中具有一定应用潜力。