Detection and verification of malting quality QTLs using wild barley introgression lines

A malting quality quantitative trait locus (QTL) study was conducted using a set of 39 wild barley introgression lines (hereafter abbreviated with S42ILs). Each S42IL harbors a single marker-defined chromosomal segment from the wild barley accession ‘ISR 42-8’ (Hordeum vulgare ssp. spontaneum) within the genetic background of the elite spring barley cultivar ‘Scarlett’ (Hordeum vulgare ssp. vulgare). The aim of the study was (1) to verify genetic effects previously identified in the advanced backcross population S42, (2) to detect new QTLs, and (3) to identify S42ILs exhibiting multiple QTL effects. For this, grain samples from field tests in three different environments were subjected to micro malting. Subsequently, a line × phenotype association study was performed with the S42ILs in order to localize putative QTL effects. A QTL was accepted if the trait value of a particular S42IL was significantly (P < 0.05) different from the recurrent parent as a control, either across all tested environments or in a particular environment. For eight malting quality traits, altogether 40 QTLs were localized, among which 35 QTLs (87.5%) were stable across all environments. Six QTLs (15.0%) revealed a trait improving wild barley effect. Out of 36 QTLs detected in a previous advanced backcross QTL study with the parent BC2DH population S42, 18 QTLs (50.0%) could be verified with the S42IL set. For the quality parameters α-amylase activity and Hartong 45°C, all QTLs assessed in population S42 were verified by S42ILs. In addition, eight new QTL effects and 17 QTLs affecting two newly investigated traits were localized. Two QTL clusters harboring simultaneous effects on eight and six traits, respectively, were mapped to chromosomes 1H and 4H. In future, fine-mapping of these QTL regions will be conducted in order to shed further light on the genetic basis of the most interesting QTLs

Discovery of four recessive developmental disorders using probabilistic genotype and phenotype matching among 4,125 families.

Discovery of most autosomal recessive disease-associated genes has involved analysis of large, often consanguineous multiplex families or small cohorts of unrelated individuals with a well-defined clinical condition. Discovery of new dominant causes of rare, genetically heterogeneous developmental disorders has been revolutionized by exome analysis of large cohorts of phenotypically diverse parent-offspring trios. Here we analyzed 4,125 families with diverse, rare and genetically heterogeneous developmental disorders and identified four new autosomal recessive disorders. These four disorders were identified by integrating Mendelian filtering (selecting probands with rare, biallelic and putatively damaging variants in the same gene) with statistical assessments of (i) the likelihood of sampling the observed genotypes from the general population and (ii) the phenotypic similarity of patients with recessive variants in the same candidate gene. This new paradigm promises to catalyze the discovery of novel recessive disorders, especially those with less consistent or nonspecific clinical presentations and those caused predominantly by compound heterozygous genotypes

Divergência genética em germoplasma de aveias silvestres com base em caracteres multicategóricos e quantitativos

As aveias silvestres são importantes fontes de genes para programas de melhoramento e sua caracterização é fundamental para a efetiva conservação e uso. Por isso, o objetivo deste estudo foi avaliar a divergência genética em uma coleção de 71 subamostras de aveias silvestres, do Banco de Germoplasma da Embrapa Trigo, com base em caracteres multicategóricos e quantitativos. Procederam-se às análises de variância, para os caracteres quantitativos, e multivariada, para ambos os tipos de caracteres. Os métodos de agrupamento UPGMA, a partir da distância euclidiana média (caracteres multicategóricos), e de ligação completa, com base na distância de Mahalanobis (caracteres quantitativos), foram os mais adequados para ilustrar a relação entre as subamostras. A pilosidade da base dos grãos foi o caractere com maior contribuição relativa para divergência genética (32,16%) e a menor contribuição foi da pilosidade do nó superior (0,081%). As subamostras divergiram quanto a vinte caracteres: pilosidade da bainha da folha inferior, bordas da lâmina imediatamente abaixo da folha bandeira, nó superior, face externa do lema e base do grão; posição da folha bandeira e das ramificações na panícula; frequência de plantas com folha bandeira recurvada; intensidade da pilosidade do nó superior e da cerosidade do lema; orientação das ramificações na panícula; comprimento dos pelos basais do grão, ráquila, panícula, glumas e planta; cor do lema, tipo de arista, número de grãos por espigueta e ciclo. O germoplasma apresenta elevada variabilidade genética e genes de interesse para o melhoramento de aveias

POLYMORPHISMS IN THE ALPHA-AMY1 GENE OF WILD AND CULTIVATED BARLEY REVEALED BY THE POLYMERASE CHAIN-REACTION

α-Amylases are the key enzymes involved in the hydrolysis of starch in plants. The polymerase chain reaction (PCR) was used to detect polymorphisms in the length of amplified sequences between the annealing sites of two primers derived from published α-amy1 gene sequences in barley. These two primers (Bsw1 and Bsw7), flanking the promoter region and the first exon, amplified two PCR fragments in barley. One of the amplified products, with the expected length of 820 bp, appeared together with another shorter PCR band of around 750 bp. This 750-bp fragment seems to be derived from an α-amylase gene not reported previously. Both of the PCR products could be amplified from the two-rowed barley varieties tested, including cv Himalaya from which the sequence information was obtained. Five of the six-rowed barley varieties also have the two PCR fragments whereas another two have only the long fragment. These two fragments seem to be unique to barley, neither of them could be amplified from other cereals; for example, wheat, rye or sorghum. These two α-amylase fragments were mapped to the long arm of 6H, the location of the α-amy1 genes, using wheat-barley addition lines. Amplification of genomic DNA from wild barley accessions with primers Bsw1 and Bsw7 indicated that both of the fragments could be present, or the long and short fragments could be present alone. The results also demonstrated that the genes specifying these two fragments could be independent from each other in barley. The conserved banding pattern of these two fragments in the two-rowed barley varieties implies that artificial selection from these genes may have played an important role in the evolution of cultivated barley from wild barley

Vasodilation to vascular endothelial growth factor in the uterine artery of the pregnant rat is blunted by low dietary protein intake

Pregnancy is associated with a substantial increase in uterine artery blood flow, which may in part result from dilation in response to vascular endothelial growth factor (VEGF). Uterine blood flow is reported to be reduced in globally diet-restricted pregnant rats. Both global and protein dietary restriction in pregnancy produce programmed effects in offspring. In this study we hypothesized that protein restriction in pregnancy impairs maternal uterine artery responses to VEGF. Vascular responses to VEGF were determined in isolated uterine arteries of pregnant (18 or 19 d of gestation) Wistar rats fed a diet containing either 18% or 9% casein throughout pregnancy. For comparison, responses to phenylephrine, potassium chloride, and acetylcholine were determined. In addition, the response of the mesenteric artery to VEGF was studied in the same animals. A significant reduction of the maximal relaxation to VEGF (p = 0.041) and in the overall response (p = 0.004) to VEGF was found in uterine arteries of the 9% compared with the 18% group, but responses to all other agonists were similar. The VEGF response was reduced by cyclooxygenase inhibition (indomethacin) in both groups. In the 18%, but not the 9%, group it was further reduced by nitric oxide synthase inhibition (N?-nitro-L-arginine methyl ester). VEGF was shown to dilate the mesenteric artery but this effect was not significantly altered by the low-protein diet. These results show an attenuated uterine artery vasodilator response to VEGF produced by a low-protein diet in pregnancy, partly because of a reduction of the nitric oxide component of VEGF-mediated relaxation