大豆开花期性状QTL定位和候选基因挖掘

大豆对光周期极为敏感,单一品种的适应范围狭窄。大豆品种在不同纬度间的适应性与开花期密切相关。为了获得更多的大豆开花期相关QTL,了解在豆适应机制,利用开花主效位点E1~E4基因型均相同的滑皮豆和齐黄26（E1e2asE3-HaE4）杂交衍生的重组自交系群体及前期基于特异长度扩增片段测序（Specific Length Amplified Fragment-sequencing, SLAF-seq）构建的高密度遗传图谱,对大豆开花期性状进行了QTL定位。共获得了分布在7条染色体上的11个QTL位点,其中4个位点（qFT8,qFT20-2,qFT14和qFT16）为本研究新发现的QTL。同时,研究发现6个QTL（qFT6-1,qFT8,qFT11-1,qFT19,qFT20-1和qFT20-2）在2013年和2014年两个环境中稳定存在。对稳定QTL位点间的基因进行生物信息学分析,筛选出4个可能参与开花期调控的候选基因。本研究结果能够为阐明大豆适应性分子机制和广适性分子育种提供一定的理论基础。     

Molecular genetic approaches to increasing mineral availability and vitamin content of cereals

The present paper summarizes the current state of knowledge on molecular genetic approaches to increasing iron and zinc availability and vitamin content in cereals. We have also attempted to integrate the scientific issues into the wider context of human nutrition. In the cereal grain, iron and zinc are preferentially stored together with phytate in membrane-enclosed globoids in the protein storage vacuole (PSV) found in the aleurone and the embryo scutellum. The PSV is accordingly central for understanding mineral deposition during grain filling and mobilization of minerals during germination. Recent studies in Arabidopsis have led to the first identification of iron and zinc transporters of the PSV and further illustrate some of the dynamics associated with mineral and phytate transport and deposition into the vacuole. This provides new opportunities for modulating iron and zinc deposition in the cereal grain. Current strategies towards increasing the iron content of the endosperm are largely based on the expression of legume ferritin genes in an endosperm-specific manner. However, it is apparent that this approach, at least in rice, only allows a two- to three-fold increase in the iron content of the grain due to exhaustion of the iron stores in leaves. Further increases thus have to rely on additional uptake and transport of iron from the root. Phytate is generally considered to be the single most important anti-nutritional factor for iron and zinc availability. In the current paper we summarize attempts to increase phytase activity in the grain by transformation and evaluate the potential of this approach as well as the reduction of phytate biosynthesis for improving the bioavailability of iron and zinc. Vitamins constitute the second important group of micronutrients in grain and we discuss current efforts to increase the amounts of provitamin A, vitamin C and vitamin E.     

油菜开花期的遗传调控及ＱＴＬ研究进展

油菜开花期影响油菜的成熟期和产量,是重要的农艺性状。目前国内外学者对油菜开花期已经展开了深入研究。本文主要从模式植物拟南芥开花期的遗传调控、油菜开花期性状QTL定位群体种类、油菜开花基因QTL定位及克隆等方面阐述研究进展,并指出目前存在的问题和对油菜开花期性状研究进行展望,以期对开花期进一步的QTL精细定位、基因克隆和分子标记辅助选择提供理论依据。     

Diallelic analysis of genetic effects determining days to flowering in kenaf

The genetic control determining the days to flowering, defined as the number of days from emergence to the beginning of flowering is considered an important characteristic for breeding purpose. We investigated this factor in kenaf (Hibiscus cannabinus L.), as part of an agroindustrial project in northwest Argentina. A diallelic cross approach was considered in this study. Six highly inbred photosensitive cultivars were used in the cross, namely, Endora, Pandora, Tainung 1, Line 42, Line 21, and Line 29. Significant differences among F₁ family means as well as among general combining ability (GCA) and specific combining ability (SCA) components were found based on the Griffing genetic-statistical method IV, Model 1. A predominant additive effect was detected for the days to flowering, giving high heritability estimates (H = DGD = 0.96; h² = 0.69), and suggests the possibility of effective selection for earliness in these cultivars. Early flowering in Line 29 was highly heritable, and therefore, is important for breeding purposes. Line 42, despite being the earliest, did not transmit this characteristic to its progenies, possibly because of epistatic genetic effects. The regression of the covariances of F₁ families on the non-recurrent parent (W_r) and the variance of the “n” families (V_r) revealed that some dominance effects also occurred in the form of a partial dominance for early flowering. These results support the evidences revealed by the analysis of means of combinations between early and late flowering lines.     

Resistant starch in cereals: Exploiting genetic engineering and genetic variation

Some of the starch consumed by humans is not digested in the small intestine. Such starch, known as resistant starch, is fermented in the large intestine and leads to the production of short chain fatty acids. Increased consumption of resistant starch is associated with improved cardio-vascular health. A high proportion of amylose in the starch consumed is correlated with increased resistant starch but other unknown aspects of starch structure may also influence the digestibility of starch. Detailed investigation of the starch biosynthetic pathway has revealed that reducing the activity of specific isoforms of branching enzymes and starch synthases can lead to increased amylose. Methods to alter the expression of and detect mutations in targeted genes involved are discussed.     

A universal protocol for identification of cereals

Plant fingerprinting and identification has increasingly become a focus in commerce and manufacturing with an emphasis on fast, reliable and cost effective high throughput techniques. GBSS1 is a well conserved single copy nuclear gene in the grass family with potential for generating a universal approach to grass fingerprinting. Alignment of DNA sequences from Poaceae members identified five well conserved regions. PCR primers designed to these regions amplified single DNA fragments on all grasses tested. DNA sequencing revealed polymorphism within these DNA fragments allowing identification at the species level. A universal sequencing primer for Poaceae enabled pyrosequencing through a 28 base pair highly polymorphic region generating unique pyrograms for rice, wheat, barley and maize. Analysis of exon/intron composition including intron length and number, of GBSS1 provided another distinct fingerprinting method for grasses. Phylogenetic utility of these fragments was demonstrated by production of phylograms consistent with previously described taxonomic relationships for the Poaceae family. The sequence polymorphism of the GBSS1 gene provides the basis for universal primer design for identification of members of the Poaceae family. The protocols developed may prove more generally useful in the distinction of plant species in other plant families.     

New approaches to potato variety identification

Summary The identification of varieties of potatoes and other crops is important at all stages of production. Traditional approaches have used morphological characters, but modern crop production increasingly demands methods that are more rapid and discriminating. Three new approaches to variety identification are described: (i) image analysis, (ii) gel electrophoresis of proteins, (iii) the use of DNA profiling (molecular markers). The advantages and disadvantages of each approach are considered and possible future developments highlighted.     

油菜开花期QTL定位和候选基因分析

为辅助选育早熟油菜品种、克隆油菜开花期基因及开发花期分子标记,以已测序的油菜品种中双11 (Z) 和重测序的油菜品系No.73290 (N)为亲本构建的含184个单株的BnaZNF2群体为材料,通过分析该群体的基因型数据和F2:3家系连续三年（2010-2012）在武汉的表型数据,对开花期QTL进行检测和整合,定位到分布在11个连锁群上的14个开花期QTL。其中只有5个QTL能在3年中重复检测到,分别是qDtF.A2-1、qDtF.A6-2、qDtF.C2-1、qDtF. C2-2 和qDtF.C3-1,贡献率在7.1%～21.1%之间。通过查阅文献和在拟南芥、水稻等作物网站上搜索,搜集到442 个与植物开花期有关的基因。基于油菜基因组物理图谱,通过生物信息学分析,在本研究定位的QTL区间上筛选到54个可能的候选基因,可以用于开花期基因的克隆。在5个主要QTL区间内分别定位到8、5、4、2和4个候选基因,其中有15个双亲中存在序列差异,可以开发开花期的功能标记用于分子标记辅助选择育种。     

Long-term approaches for the control of Striga in cereals: field management options

Farmers in Africa have limited resources to invest in Striga control practices and longer term, low-input approaches are needed. Long-term Striga control approaches focus on controlling the production of new Striga seeds and on reducing the number of seeds in the soil. Several seasons of hand weeding are required before the beneficial effect on the cereal crop can be observed. Rotations with trap crops can reduce Striga seed banks but selection of a rotation crop should be based on socio-economic factors such as market value in addition to whether or not it can stimulate Striga seeds to germinate. Striga seed banks can be readily reduced in suppressive soils. Organic matter and fertilizer additions may help induce suppressiveness. Extension of long-term Striga control approaches requires intensive interaction with farmers.     

Comparative defoliation tolerance of temperate perennial grasses

The defoliation tolerance of cultivars of four temperate perennial pasture grasses, perennial ryegrass (Lolium perenne, cv. Yatsyn1), phalaris (Phalaris aquatica cv. Australian), tall fescue (Festuca arundinaceae cv. Demeter) and cocksfoot (Dactylis glomerata cv. Porto), was determined under controlled conditions over a period of 12 weeks. Undefoliated plants were compared with defoliated plants, where only half of one leaf was left intact at the initial defoliation, and leaf regrowth was harvested every 3–4 d. The growth responses measured were plant tiller number, dry weight, relative leaf regrowth rate, root:shoot ratio, sheath:stem ratio and specific leaf weight. All species showed morphological adaptations that potentially increased their ability to tolerate defoliation (e.g. increased allocation to shoot at the expense of roots and lower specific leaf weights) but cocksfoot was found to be the most defoliation‐tolerant and perennial ryegrass the least. The adaptation that favoured cocksfoot most strongly was high sheath:stem ratio, which, it is proposed, allowed it to maintain photosynthesis and a level of carbon supply sufficient to support regrowth throughout the experiment. The strategy of perennial ryegrass which favours leaf growth and leads to rapid leaf turnover rates made it particularly susceptible to defoliation under the conditions of this experiment. This highlights the likely importance of defoliation‐avoidance responses in explaining the well‐known grazing resistance of this species. Phalaris and tall fescue showed responses that were intermediate between the other two species. The importance of defoliation‐avoidance mechanisms and implications for grazing management are discussed.     

甘蓝型油菜遗传图谱的构建及开花期的QTL分析

在由两个春性甘蓝型油菜双低品种DH401（早花）和Q2（迟花）的F1代植株通过小孢子培养所获得的DH（doubled haploid）群体中，应用SSR、SRAP及AFLP标记构建了一张遗传连锁图谱，并对开花期性状进行了数量性状座位（QTL）分析。在亲本间共检测到263个有多态性的遗传标记，其中SSR标记有88个、SRAP标记101个及AFLP标记74个。其中248个标记分布于19个连锁群，总遗传距离为1634.7 cM，标记间平均遗传距离为6.6 cM，标记偏分离比例达到27.4% (p<0.01)且主要集中在第4、5连锁群。应用QTLMAPPER 1.6在武汉、和政分别检测到2个和4个控制开花期的主效QTL位点，分别解释了68.63%和75.83的开花期表型变异，其中有2个主效QTL位点在这两地同时被检测到。另外也分析了影响开花期的上位效应并探讨了本研究结果在实际育种中的意义。     

Heat stress effects around flowering on kernel set of temperate and tropical maize hybrids

Final kernel number in the uppermost ear of temperate maize (Zea mays L.) hybrids is smaller than the potential represented by the number of florets differentiated in this ear, and than the number of silks exposed from it (i.e., kernel set <1). This trend increases when stressful conditions affect plant growth immediately before (GS₁) or during (GS₂) silking, but the magnitude of change has not been documented for heat stress effects and hybrids of tropical background. In this work we evaluated mentioned traits in field experiments (Exp₁ and Exp₂), including (i) two temperature regimes, control and heated during daytime hours (ca. 33-40 °C at ear level), (ii) two 15-d periods during GS₁ and GS₂, and (iii) three hybrids (Te: temperate; Tr: tropical; TeTr: Te × Tr). We also measured crop anthesis and silking dynamics, silk exposure of individual plants, and the anthesis-silking interval (ASI). Three sources of kernel loss were identified: decreased floret differentiation, pollination failure, and kernel abortion. Heating affected all surveyed traits, but negative effects on flowering dynamics were larger (i) for anthesis than for silking with the concomitant decrease in ASI, and (ii) for GS₁ than for GS₂. Heat also caused a decrease in the number of (i) florets only when performed during GS₁ (−15.5% in Exp₁ and −9.1% in Exp₂), and only among Te and TeTr hybrids, (ii) exposed silks of all GS × Hybrid combinations, and (iii) harvestable kernels (mean of −51.8% in GS₁ and −74.5% in GS₂). Kernel abortion explained 95% of the variation in final kernel numbers (P < 0.001), and negative heat effects were larger on this loss (38.6%) than on other losses (≤11.3%). The tropical genetic background conferred an enhanced capacity for enduring most negative effects of heating.     

Candidate genes underlying QTL for flowering time and their interactions in a wide spring barley (Hordeum vulgare L.) cross

Response to vernalization and photoperiod are the main determinants controlling the time to flowering in temperate cereals. While the individual genes that dete...     

Comparative transcriptional analysis and identification of hub genes associated with wing differentiation of male in Aphis gossypii

Background: Aphis gossypii Glover(Hemiptera: Aphididae), a worldwide polyphagous phloem-feeding agricultural pest, has three wing morphs(winged parthenogenetic female, gynopara, and male) in the life cycle. The exclusive males could fly from summer hosts to winter hosts, which are essential for gene exchanges of cotton aphid populations from di erent hosts or regions. However, the molecular mechanism of wing di erentiation of male in A. gossypii remains unclear.Results: Morphological observation...     

CRISPR/Cas9-engineered mutation to identify the roles of phytochromes in regulating photomorphogenesis and flowering time in soybean

Soybean(Glycine max) responds to ambient light variation by undergoing multiform morphological alterations, influencing its yield potential and stability in the field. Phytochromes(PHYs) are plant-specific red(R) and far-red(FR) light photoreceptors mediating photomorphogenesis and photoperiodic flowering. As an ancient tetraploid, soybean harbors four PHYA, two PHYB, and two PHYE paralogs. Except for GmPHYA2/E4 and GmPHYA3/E3, which have been identified as photoperiod-dependent flowering repres...     

A differentially methylated region of the ZmCCT10 promoter affects flowering time in hybrid maize

Flowering time(FT) is a key maize domestication trait, variation in which allows maize to grow in a wide range of latitudes. Although previous studies have investigated the genetic control of FT-related traits per se, few studies of FT hybrid performance have been published. We characterized the genomic architecture associated with hybrid performance for FT in a hybrid panel by testcrossing Chang 7–2 with 328Ye478 × Qi319 recombinant inbred lines(RILs). We identified 11 quantitative trait loci(Q...     

Antibodies against wheat xylanase inhibitors as tools for the selective identification of their homologues in other cereals

Polyclonal antibodies (PAbs) were raised against wheat (Triticum aestivum L.) TAXI- and XIP-type xylanase inhibitors by rabbit immunization. A small contaminant in both antigens, not detected by SDS-PAGE and later identified through Western blot as a recently discovered third type of xylanase inhibitor from wheat, i.e. thaumatin-like xylanase inhibitor (TL-XI), led to the coproduction of PAbs against this protein in the rabbits. To obtain inhibitor-specific PAbs, the PAbs against TAXI, XIP and TL-XI were separated by affinity chromatography using immobilised recombinant and native xylanase inhibitors. The purified PAbs allowed the immunoquantification of each type of wheat xylanase inhibitor using Western blot and densitometric analysis against purified inhibitor standards. The method allowed the detection of the purified inhibitors at the 20 ng level. As the PAbs against the wheat xylanase inhibitors cross-reacted with their homologous targets from other cereals, immunoprobing allowed identification of XIP homologues in oats (Avena sativa L.) and TL-XI homologues in durum wheat (Triticum durum Desf.) and rye (Secale cereale L.).     

Ear structure and the resistance of cereals to aphids

In 1977 and 1978 in the field the cereal aphid Sitobion avenae F. (Hemiptera:Aphididae) was a pest on winter wheat (cv. Maris Huntsman), but was rare on winter barley (cv. Maris Otter). The results of laboratory experiments can only partly account for this observation. Alates showed no preference between leaves of wheat and barley, flag leaves of wheat and ears of barley, or ears of wheat and barley, the developmental stages available for colonization in the field. Developmental time, teneral weight, reproductive rate and offspring size of apterae were similar when reared on ears of wheat and barley. However, the proportion that developed into alatae and adult mortality were significantly higher on barley. That aphids fed on the rachis of wheat and the glumes of barley was attributed to differences in the ear structure of the two cereals. The possible role of plant structure in determining the resistance of cereals to aphids in the field is discussed.     

Reducing the incidence of allergy and intolerance to cereals

This paper reviews studies on allergy, intolerance and sensitivity to cereals, especially to wheat, barley, rye, maize, rice and oats with regard to reducing their incidences. Prevalence of allergy to cereals is generally low; prevalence of other cereal-related diseases are highest for wheat and lowest for oats. Compared to the other cereals, wheat (and its components wheat starch and vital gluten) are most abundantly applied in a broad range of food products world-wide, which justifies the major focus of this review on wheat. Current knowledge on diagnosis of the cereal-related diseases and on detection and characterization of the relevant proteins is discussed in the context of the development of prevention strategies. Aiming at their design and implementation, such strategies require building of knowledge frameworks at the primary, secondary and tertiary prevention levels. In this regard, selection and breeding of low-allergenic/low-intoleragenic crop varieties, application of processing and technological approaches, and the introduction of alternative safe cereal crops is discussed. Sustainable reduction of immune-related diseases in general (including cereal allergies and intolerances) is discussed with regard to eating habits and lifestyle factors, human genetic and physiological characteristics, and the role of the intestinal micro-flora.     

栽培因子对棉株蕾花铃形成时空分布影响的研究

本研究采用二次回归组合设计的最优混合设计(311设计)，在湖南特殊的环境条件与栽培技术体系下探讨了栽培因子对棉株不同座果点蕾花铃的影响．即伏前桃在总铃数中所占的比例随播期推迟而减少，随密度增大而略有增加，施氮量过多或过少均减少伏前桃的比例：秋桃的比例随播期推迟而增加，随密度增大反而降低，随施氮量的增加而增加，伏桃在总铃敷中的比例最高，各个处理平均达到62％左右。根据三桃的总数与比例得出处理3为较好的栽培模式，即播期为4月9日，密度为19755株／hm^2，施氮量为337．5kg／hm^22。