Genetic mapping,marker assisted selection and allelic relationships for the Pu6 gene conferring rust resistance in sunflower

Rust resistance in the sunflower line P386 is controlled by Pu₆, a gene which was reported to segregate independently from other rust resistant genes, such as R₄. The objectives of this work were to map Pu₆, to provide and validate molecular tools for its identification, and to determine the linkage relationship of Pu₆ and R₄. Genetic mapping of Pu₆ with six markers covered 24.8 cM of genetic distance on the lower end of linkage Group 13 of the sunflower consensus map. The marker most closely linked to Pu₆ was ORS316 at 2.5 cM in the distal position. ORS316 presented five alleles when was assayed with a representative set of resistant and susceptible lines. Allelism test between Pu₆ and R₄ indicated that both genes are linked at a genetic distance of 6.25 cM. This is the first confirmation based on an allelism test that at least two members of the R_adv/R₄/R₁₁/ R_13a/R_13b/Pu₆ cluster of genes are at different loci. A fine elucidation of the architecture of this complex locus will allow designing and constructing completely new genomic regions combining genes from different resistant sources and the elimination of the linkage drag around each resistant gene.     

R-41, a sunflower restorer inbred line, carrying two genes for resistance against a highly virulent Spanish population of Orobanche cernua

The inheritance of resistance to a highly virulent population of sunflower broomrape (Orobanche cernua) has been studied in R-41, a Spanish sunflower restorer inbred line. Using the cytoplasmic male-sterile inbred line HA-89 (cms; very susceptible to this population of broomrape) as a female parent, progenies of the cross with R-41, i.e. Fl, F2 and BC1 to both parents, as well as the parental lines, were analysed for their reaction to the broomrape population EC-94. The goodness of fit of the observed vs expected segregation ratios indicated that the inheritance of resistance to broomrape in line R-41 is conferred by two independent dominant genes.     

延安不同菊芋品种比较试验研究

筛选出适宜延安种植的菊芋品种,解决延安菊芋品种单一的问题,促进延安菊芋产业化发展。对引进的6个菊芋品种和1个当地品种进行田间比较试验,调查各品种田间的生育期、农艺性状和经济性状。试验结果表明,‘廊芋1号’和‘廊芋2号’2个品种的综合性状表现较好,其产量分别为57378.68、56228.10 kg/hm²,较对照增产分别为5.11%、3.00%。其余品种表现一般,产量均低于对照品种,需继续试种观察。 ‘廊芋1号’和‘廊芋2号’较适合在延安种植,可进行示范推广。     

异源表达菊芋HtHCT基因对受体植物木质素相关生理生化指标的影响

羟基肉桂酰辅酶A:莽草酸/奎宁酸羟基肉桂酰转移酶（HCT）是木质素合成过程中的关键酶之一。本研究构建了菊芋HtHCT基因的植物表达载体pCAMBIA1390-HtHCT,分别对拟南芥和本氏烟进行遗传转化,并对转基因植株进行生理生化指标测定。PCR和RT-PCR结果表明,HtHCT基因已经插入到受体植物基因组中,并能进行转录;转基因植株生理生化指标检测表明,HtHCT基因能够调节拟南芥和本氏烟中木质素的含量及组成,并对受体材料的类黄酮合成亦有一定的影响。     

菊芋悬浮细胞系的建立及其导管分子的体外分化

利用菊芋地下块茎作外植体,在附加1.2mg·L~(-1)2,4-D 的 MS 培养基上诱导愈伤组织形成,经同样 MS 液体培养基培养形成悬浮系;菊芋悬浮细胞转入含5.0mg·L~(-1)的6-BAP、1.0mg·L~(-1)2,4-D 的 MS 液体培养基内.经9d 培养可使约30%～50%悬浮细胞转化为具次生壁条纹的导管分子。     

Precision phenotyping of imidazolinone-induced chlorosis in sunflower

Chlorosis level is a useful parameter to assess imidazolinone resistance in sunflower (Helianthus annuus L.). The aim of this study was to quantify chlorosis through two different methods in sunflower plantlets treated with imazapyr. The genotypes used in this study were two inbred lines reported to be different in their resistance to imidazolinones. Chlorosis was evaluated by spectrophotometrical quantification of photosynthetic leaf pigments and by a bioinformatics-based color analysis. A protocol for pigment extraction was presented which improved pigment stability. Chlorophyll amount decreased significantly when both genotypes were treated with 10 μM of imazapyr. Leaf color was characterized using Tomato Analyzer^® color test software. A significant positive correlation between color reduction and chlorophyll concentration was found. It suggests that leaf color measurement could be an accurate method to estimate chlorosis and infer chlorophyll levels in sunflower plants. These results highlight a strong relationship between imidazolinone-induced chlorosis and variations in leaf color and in chlorophyll concentration. Both methods are quantitative, rapid, simple, and reproducible. Thus, they could be useful tools for phenotyping and screening large number of plants when breeding for imidazolinone resistance in this species.     

Genetic variability in plants regenerated from in vitro culture of sunflower (Helianthus annum L.)

In vitro regenerated sunflower (Helianthus annuus L.) plants (R₁) were self-fertilized and the R₂ generation was evaluated for qualitative traits. A broad range of phenotypic variation was observed and mutation frequencies were calculated. Some in vitro induced variant phenotypes were similar to known spontaneous or induced mutations in sunflower, while others were new. Chlorophyll and carotenoid deficiencies, chimaerical variegation, fasciated stem and capitulum, abnormal shoot development, and other morphological variations, were noted. Substitution of anthers with petaloid structures in a disk-floret mutant indicates a possible homeotic mutation induced by in vitro tissue culture.     

菊芋在民勤干旱沙区种植试验研究

2007年通过在民勤干旱沙区进行菊芋种植试验,结果表明:菊芋具有极强的抗旱抗逆能力、固沙和抗风沙能力、繁殖力强等生态适应性,在适宜的条件下,种植后不需灌水即可正常生长,而且生长量大、长势好,是优良的生态经济型防风固沙植物.因此,菊芋适宜在干旱、半干旱沙漠化地区推广种植.     

菊芋根系分泌物改良滨海盐土的微生物机制

[目的]探究菊芋在滨海盐土改良过程中的作用机制,分析菊芋和碱蓬根系分泌物的组分差异,明确土壤微生态环境的变化规律,进一步为盐土改良提供理论依据.[方法]以种植菊芋和自然碱蓬植被为样地,对菊芋和碱蓬的根系分泌物进行对比分析,研究在根系分泌物作用下土壤微生物数量,微生物量碳氮,微生物群落结构以及土壤酶活性的变化,从而系统地...     

Intraspecific Relationship of Plasmopara halstedii Isolates Differing in Pathogenicity and Geographic Origin Based on ITS Sequence Data

Sequence parts of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA were analysed to screen for the intraspecific variability of a non-coding genomic region in 15 Plasmopara halstedii populations of different pathotype and geographic origin. Samples revealed uniformity in a ca. 790 Bp fragment comprising of the ITS-1, 5.8S and front parts of the ITS-2. In contrast, clear differences were found in a ca. 810 Bp fragment of the ITS-2 thus allowing differentiation between populations of pathotype 100, 310 and 330 and a group of populations representing pathotypes 700, 701, 703, 710 and 730. Samples of pathotypes 700 to730 originated from Slovakia, France, and Germany, but were uniform in both ITS sequence parts, thus indicating very recent origin of these highly aggressive physiological races. The potential use of ITS sequences for pathotype differentiation and phylogenetic studies in P. halstedii is discussed.