基于染色体置换系的普通野生稻耐盐性QTL定位

本研究分别利用SSR标记、InDel标记以及简化基因组测序技术对一套以普通野生稻为供体亲本,9311为受体亲本的染色体置换系进行基因型鉴定,并通过对其不同生育期的耐盐性鉴定,共发掘2个与发芽期耐盐相关的QTL,13个与苗期耐盐性相关的QTL。其中与苗期存活率相关的QTL qSSR5.1、苗期耐盐等级相关的QTL qSSG5.1均被定位于同一位点,该位点对苗期存活率、苗期耐盐等级均具有增效作用,贡献率分别为6.36%、8.13%。在此QTL内包含与非生物胁迫相关基因OsDi19-1。经序列比对发现,OsDi19-1启动子区域在两亲本间存在较大差异,且受到盐胁迫时该基因表达量上升。同时,鉴定出水稻芽期耐盐的优异种质资源CSSL72、苗期耐盐的优异种质资源CSSL23、CSSL153,为水稻育种中耐盐性的改良提供了新的种质资源。     

水稻根系遗传育种研究进展

根系作为水稻(Oryza sativa)植株的重要组成部分, 在水稻生长发育过程中发挥多种作用, 包括植物的固定、水分和营养物质的获取以及氨基酸和激素的生物合成等, 其形态结构和生理功能与水稻产量和稻米品质以及抗性等密切相关。目前, 通过遗传及生化等诸多手段, 已挖掘到较多水稻根系QTLs与控制基因。该文综述了水稻根系QTL和基因的研究进展, 并对未来根系研究进行展望, 以期为进一步克隆水稻根系基因和完善水稻理想株型模型提供参考。     

Variation in phosphorus and sulfur content shapes the genetic architecture and phenotypic associations within the wheat grain ionome

Dissection of the genetic basis of wheat ionome is crucial for understanding the physiological and biochemical processes underlying mineral accumulation in seeds, as well as for efficient crop breeding. Most of the elements essential for plants are metals stored in seeds as chelate complexes with phytic acid or sulfur‐containing compounds. We assume that the involvement of phosphorus and sulfur in metal chelation is the reason for strong phenotypic correlations within ionome. Adjustment of element concentrations for the effect of variation in phosphorus and sulfur seed content resulted in drastic change of phenotypic correlations between the elements. The genetic architecture of wheat grain ionome was characterized by quantitative trait loci (QTL) analysis using a cross between durum and wild emmer wheat. QTL analysis of the adjusted traits and two‐trait analysis of the initial traits paired with either P or S considerably improved QTL detection power and accuracy, resulting in the identification of 105 QTLs and 617 QTL effects for 11 elements. Candidate gene search revealed some potential functional associations between QTLs and corresponding genes within their intervals. Thus, we have shown that accounting for variation in P and S is crucial for understanding of the physiological and genetic regulation of mineral composition of wheat grain ionome and can be implemented for other plants.     

Rapid generation of ecologically relevant behavioral novelty in experimental cichlid hybrids

The East African cichlid radiations are characterized by repeated and rapid diversification into many distinct species with different ecological specializations and by a history of hybridization events between nonsister species. Such hybridization might provide important fuel for adaptive radiation. Interspecific hybrids can have extreme trait values or novel trait combinations and such transgressive phenotypes may allow some hybrids to explore ecological niches neither of the parental species could tap into. Here, we investigate the potential of second‐generation (F2) hybrids between two generalist cichlid species from Lake Malawi to exploit a resource neither parental species is specialized on: feeding by sifting sand. Some of the F2 hybrids phenotypically resembled fish of species that are specialized on sand sifting. We combined experimental behavioral and morphometric approaches to test whether the F2 hybrids are transgressive in both morphology and behavior related to sand sifting. We then performed a quantitative trait loci (QTL) analysis using RADseq markers to investigate the genetic architecture of morphological and behavioral traits. We show that transgression is present in several morphological traits, that novel trait combinations occur, and we observe transgressive trait values in sand sifting behavior in some of the F2 hybrids. Moreover, we find QTLs for morphology and for sand sifting behavior, suggesting the existence of some loci with moderate to large effects. We demonstrate that hybridization has the potential to rapidly generate novel and ecologically relevant phenotypes that may be suited to a niche neither of the parental species occupies. Interspecific hybridization may thereby contribute to the rapid generation of ecological diversity in cichlid radiations.     

大豆蛋白含量新位点qPRO-19-1的定位

大豆是重要的粮食作物和经济作物,其籽粒蛋白约为40%,是植物蛋白的重要来源之一。国产大豆主要用于食用,提高大豆蛋白含量是主要的育种目标。因此,发掘大豆蛋白含量相关基因,对开发分子标记并培育高蛋白食用大豆具有重要意义。本研究以低蛋白大豆品种中黄35为母本,以源自日本的高蛋白大豆十胜长叶为父本,构建了重组自交系(RIL,recombination inbred lines)群体。利用集群分离分析法(BSA,bulked segregant analysis)在3条染色体筛选出9个与蛋白含量相关的SSR标记,其中位于19号染色体的QTL尚未见报道。进一步利用完备区间作图法(ICIM-ADD)分析RIL群体F_2:15和F_2:16,在19号染色体重复定位了1个蛋白质含量相关QTL qPRO-19-1,位于分子标记SSR_19_38和SSR_19_59之间,LOD值分别为3.43和3.98,贡献率分别为7.81%和14.87%,高蛋白等位基因来自于高蛋白亲本十胜长叶。qPRO-19-1的定位区间长度为385 kb,共有注释基因36个。本研究定位了蛋白质含量相关的新位点qPRO-19-1,为大豆高蛋白基因的图位克隆及分子标记育种奠定了基础。     

Disentangling Two QTL on Porcine Chromosome 12 for Backfat Fatty Acid Composition

A previous study allowed the identification of two QTL regions at positions 11–34 cM (QTL1) and 68–76 cM (QTL2) on porcine chromosome SSC12 affecting several backfat fatty acids in an Iberian x Landrace F2 intercross. In the current study, different approaches were performed in order to better delimit the quoted QTL regions and analyze candidate genes. A new chromosome scan, using 81 SNPs selected from the Porcine 60KBeadChip and six previously genotyped microsatellites have refined the QTL positions. Three new functional candidate genes (ACOX1, ACLY, and SREBF1) have been characterized. Moreover, two putative promoters of porcine ACACA gene have also been investigated. New isoforms and 24 SNPs were detected in the four candidate genes, 19 of which were genotyped in the population. ACOX1 and ACLY SNPs failed to explain the effects of QTL1 on palmitic and gadoleic fatty acids. QTL2, affecting palmitoleic, stearic, and vaccenic fatty acids, maps close to the ACACA gene location. The most significant associations have been detected between one intronic (g.53840T > C) and one synonymous (c.5634T > C) ACACA SNPs and these fatty acids. Complementary analyses including ACACA gene expression quantification and association studies in other porcine genetic types do not support the expected causal effect of ACACA SNPs.     

Domestication‐related variation in social preferences in chickens is affected by genotype on a growth QTL

A growth‐related QTL on chicken chromosome 1 has previously been shown to influence domestication behaviour in chickens. In this study, we used Red Junglefowl (RJF) and White Leghorn (WL) as well as the intercross between them to investigate whether stress affects the way birds allocate their time between familiar and unfamiliar conspecifics in a social preference test (‘social support seeking’), and how this is related to genotype at specific loci within the growth QTL. Red Junglefowl males spent more time with unfamiliar chickens before the stressful event compared to the other birds, whereas all birds except WL males tended to spend less time with unfamiliar ones after stress. A significant QTL locus was found to influence both social preference under undisturbed circumstances and social support seeking. The WL allele at this QTL was associated not only with a preference for unfamiliar individuals but also with a shift towards familiar ones in response to stress (social support seeking). A second, suggestive QTL also affected social support seeking, but in the opposite direction; the WL allele was associated with increased time spent with unfamiliar individuals. The region contains several possible candidate genes, and gene expression analysis of a number of them showed differential expression between RJF and WL of AVPR2 (receptor for vasotocin), and possibly AVPR1a (another vasotocin receptor) and NRCAM (involved in neural development) in the lower frontal lobes of the brains of RJF and WL animals. These three genes continue to be interesting candidates for the observed behavioural effects .     

Genetic polymorphisms and protein structures in growth hormone,growth hormone receptor,ghrelin, insulin-like growth factor 1 and leptin in Mehraban sheep

The somatotropic axis, the control system for growth hormone (GH) secretion and its endogenous factors involved in the regulation of metabolism and energy partitioning, has promising potentials for producing economically valuable traits in farm animals. Here we investigated single nucleotide polymorphisms (SNPs) of the genes of factors involved in the somatotropic axis for growth hormone (GH1), growth hormone receptor (GHR), ghrelin (GHRL), insulin-like growth factor 1 (IGF-I) and leptin (LEP), using polymerase chain reaction–single-strand conformation polymorphism (PCR–SSCP) and DNA sequencing methods in 452 individual Mehraban sheep. A nonradioactive method to allow SSCP detection was used for genomic DNA and PCR amplification of six fragments: exons 4 and 5 of GH1; exon 10 of GH receptor (GHR); exon 1 of ghrelin (GHRL); exon 1 of insulin-like growth factor-I (IGF-I), and exon 3 of leptin (LEP). Polymorphisms were detected in five of the six PCR products. Two electrophoretic patterns were detected for GH1 exon 4. Five conformational patterns were detected for GH1 exon 5 and LEP exon 3, and three for IGF-I exon 1. Only GHR and GHRL were monomorphic. Changes in protein structures due to variable SNPs were also analyzed. The results suggest that Mehraban sheep, a major breed that is important for the animal industry in Middle East countries, has high genetic variability, opening interesting prospects for future selection programs and preservation strategies.