利用90K基因芯片进行小麦株高QTL分析

为给小麦株高标记辅助选择提供可供选择的分子标记,并进一步对株高QTL进行精细定位及相关基因克隆,以小麦骨干亲本周8425B和小偃81衍生的包含102个家系的RIL群体(F_8)为材料,利用90K芯片标记构建高密度遗传图谱,在3个环境下对株高进行QTL检测。结果表明,所构建的图谱含有9 290个SNP标记,覆盖了小麦21条染色体的63个连锁群,图谱总长3 894.64cM,平均标记密度为0.42cM。共检测到9个控制株高的QTL,分布于1B、4A、4D、6B、7A、7B和7D染色体上,变异解释率为2.23%~16.25%。QPh.nafu.4D、QPh.nafu.4A、QPh.nafu.1B-2与前人定位到的位置相同或相近。QPh.nafu.7A具有较大的LOD值(8.17)和变异解释率(14.69%),为主效QTL。QPh.nafu.6B、QPh.nafu.7B-1、QPh.nafu.7B-2均能在多个环境下使用多种QTL检测方法定位到,可能为新的较稳定的控制株高的QTL。     

小麦白斑突变体I30的特征特性及遗传分析

类病斑突变体是研究植物程序性死亡和抗病性的理想材料。为了丰富小麦斑点突变体的研究,对叠氮化钠诱变小麦品种陕农33产生的稳定遗传的白斑突变体I30进行了特征特性研究和遗传分析。结果表明,突变体I30从三叶期开始表现白色块斑和长条纹。锥虫蓝染色和DAB染色显示,I30斑点处出现细胞死亡和H_2O_2积累现象。透射电子显微镜观察表明,I30的叶绿体形状发生改变,数目减少,基粒垛叠高度无序,部分甚至降解。农艺性状调查结果表明,I30的株高、单株有效穗数、穗粒数、穗长和结实率与野生型间无显著差异,但千粒重、穗粒重、单株产量、旗叶长度和宽度显著低于野生型。遗传分析表明,I30由1对隐性核基因控制。利用BSA+660K基因芯片技术,将该基因定位于小麦6D染色体上,位于SSR分子标记Xcfd190和6DS-5之间,遗传距离分别为6.4cM和9.1cM。     

Investigation and genetic mapping of a Glomerella leaf spot resistance locus in apple

Apple Glomerella leaf spot (GLS) is a severe fungal disease that damages apple leaves during the summer in China. Breeding new apple varieties that are resistant to the disease is considered the best way of controlling GLS. Fine mapping and tightly linked marker are critically essential for the preselection of resistant seedlings. In this study, a population of 207 F₁ individuals derived from a cross between ‘Golden Delicious’ and ‘Fuji’ was used to construct a fine simple sequence repeat (SSR)‐based genetic linkage map. The position of R_gls, a locus responsible for resistance to GLS, was identified on apple linkage group (LG) 15 using SSR markers CH05g05 and CH01d08, which was adapted from a published set of 300 SSR markers that were developed using the bulked segregant analysis (BSA) method. These two SSR markers flanked the gene, and its recombination rate was 8.7% and 23.2%, respectively. A total of 276 newly developed SSR markers around the target region and designed from the genome apple assembly contig of LG15 were screened. Only nine of these were determined to be linked to the R_gls locus. Thus, a total of 11 SSR markers were in linkage with R_gls, and mapped at distances ranging from 0.5 to 33.8 cM. The closest marker to the R_gls locus was S0405127, which showed a genetic distance of approximately 0.5 cM. The first mapping of the gene R_gls was constructed, and the locations of the 11 effective primers in the ‘Golden Delicious’ apple genome sequence were anchored. This result facilitates better understanding of the molecular mechanisms underlying the trait of resistance to GLS and could be used in improving the breeding efficiency of GLS‐resistant apple varieties.     

Mapping and validation of the quantitative trait loci for leaf stay‐green‐associated parameters in maize

Functional stay‐green is generally regarded as a desirable trait of varieties in major crops including maize. In this study, we used an F_3:4 recombinant inbred line population with 165 lines from a cross between a stay‐green inbred line (Zheng58) and a model inbred line (B73) using 211 polymorphic simple sequence repeat markers to map quantitative trait loci for three stay‐green‐associated parameters, chlorophyll content, photosystem II photochemical efficiency and stay‐green area, at maturity stage, detected a total of 23 quantitative trait loci (QTL) on nine chromosomes. Single QTL explained 3.7–13.5% of the phenotypic variance. Additionally, we validated some important stay‐green QTL using a heterogeneous inbred family approach and found that the stay‐green‐associated parameters were significantly correlated with the plant yield. This study may contribute to a better insight into the regulatory mechanism behind leaf stay‐green in maize and a novel development of elite maize varieties with delayed leaf senescence through molecular marker‐assisted selection.     

Soybean plant height QTL mapping and meta‐analysis for mining candidate genes

Plant height is closely related to seed yield of soybean. The goal of this study was to identify important loci affecting soybean plant height using meta‐analysis based on a reference physical map. Plant height related to QTLs was mapped across eight years with a RIL population by WinQTLCart v2.5. 182 QTLs related to plant height of soybean from database and our research were collected, and each QTL was projected onto the soybean physical map by software BioMercator v2.1. The confidence interval of meta‐QTL ranged from 0.09 to 5.07 Mb, and the mean phenotypic variance ranged from 4.9% to 73.0%. Furthermore, 4,259 candidate genes were located in these consensus QTLs, and 40 of them were involved in the plant growth and stem elongation and annotated as plant hormone signal transduction (pathway ID ko04075) in KEGG pathway. These results would lay a foundation for fine mapping of QTLs/genes related to plant height and marker‐assisted selection for breeding in soybean.     

Genomewide association study reveals novel quantitative trait loci associated with resistance towards Septoria tritici blotch in North European winter wheat

Fungal diseases are a major constraint for wheat production. Effective disease resistance is essential for ensuring a high production quality and yield. One of the most severe fungal diseases of wheat is Septoria tritici blotch (STB), which influences wheat production across the world. In this study, genomewide association mapping was used to identify new chromosomal regions on the wheat genome conferring effective resistance towards STB. A winter wheat population of 164 North European varieties and breeding lines was genotyped with 15K single nucleotide polymorphism (SNP) wheat array. The varieties were evaluated for STB in field trials at three locations in Denmark and across 3 years. The association analysis revealed four quantitative trait loci, on chromosomes 1B, 2A, 5D and 7A, highly associated with STB resistance. By comparing varieties containing several quantitative trait loci (QTL) with varieties containing none of the found QTL, a significant difference was found in the mean disease score. This indicates that an effective resistance can be obtained by pyramiding several QTL.     

水稻紫鞘染色体片段代换系Z519的鉴定及PSH1候选基因分析

花青素是广受人们喜爱的植物色素,在食品加工、杂种纯度鉴定中具有重要的作用。本研究鉴定了一个以日本晴为受体、优良紫鞘恢复系R225为供体亲本的紫鞘水稻染色体片段代换系Z519。Z519共含有16个代换片段,分布于除第10染色体外的其他11条染色体,平均长度为6.85 Mb。Z519在芽鞘3 mm时鞘尖呈现紫色,其后在叶鞘、叶缘、茎维管束和柱头等部位出现紫色线条,而日本晴各部位均为绿色。Z519叶鞘中花青素含量极显著高于日本晴,剑叶中没有显著差异。与受体日本晴相比,Z519的株高显著降低,千粒重、主穗总粒数和实粒数显著增加,有效穗数、主穗长和结实率无显著差异。进一步以日本晴与Z519杂交产生的F1和F2群体对紫鞘基因进行了遗传分析和分子定位。该紫鞘表型受显性单基因控制,位于第1染色体In Del标记L03和SSR标记L01之间37.8 kb的区域,被命名为PSH1。对该区间进行候选基因预测和测序,Z519在一个编码质体ATP/ADP转运蛋白的LOC_Os01g45910基因第一外显子的第238~252碱基的GTG重复区又多插入了GTG 3个碱基,导致增加了一个甘氨酸。q RT-PCR结果进一步表明其表达量在Z519中明显降低,初步确定LOC_Os01g45910是PSH1的候选基因。该研究为PSH1调控花青素的分子机制奠定了良好基础。     

水稻颖花持续开放突变体sostenuto floret opening(sfo1)的鉴定与基因定位

水稻颖花开放是其生殖发育一个关键生理过程,对受精和随后种子发育具有重要影响。本文报道了一个与水稻颖花开放相关的突变体,来源于籼稻保持系西农1B的EMS(ethyl methane sulfonate)诱变群体。该突变体表现为开颖后浆片失水萎缩过程缓慢,内外稃持续开裂不闭合,暂命名为水稻颖花持续开放sostenuto floret opening 1(sfo1)突变体。遗传分析表明sfo1性状受1对隐性单基因控制,利用群体分离分析法(bulked segregation analysis,BSA)将SFO1基因定位在第5染色体SSR标记RM1054和IN/DEL标记ZTQ51之间,物理距离113 kb,含注释基因15个。本研究结果为SFO1基因的图位克隆和功能研究奠定了基础。     

苹果分子标记及辅助育种研究进展

从基于集群分离分析法、杂交群体、全基因组关联分析和功能基因分子标记4个方面对苹果相关的分子标记及其在辅助育种上的应用进行了综述,为苹果分子标记辅助育种和揭示重要性状的遗传提供依据。