Efficiency of IRAP and ITS-RFLP marker systems in accessing genetic variation of Pyrenophora graminea

The usefulness of IRAP (inter-retrotransposon amplified polymorphism) and ITS-RFLP (restriction of PCR-amplified internal transcribed spacers of the rDNA) markers in the analysis of 39 Pyrenophora graminea isolates was determined. Each marker system could discriminate between all of the isolates in detecting polymorphism, albeit with variable efficiency. IRAP and ITS-RFLP produced 85% and 77% polymorphic bands, respectively, with a corresponding mean polymorphic information content (PIC) of 0.38 and 0.36. The IRAP marker index ratio (2.41) was higher than ITS-RFLP (1.50). On one hand, the quality nature of data (QND) was higher for ITS-RFLP (0.169) than IRAP (0.093). However, correlation between both marker similarity matrices was significant (r = 0.34, p < 0.05). These findings suggest their combined use in phylogenetic analysis. To our knowledge, this is the first report of a comparison involving these two advanced DNA marker systems

FUZZY LOGIC CONTROLLER IMPLEMENTATION FOR PHOTOVOLTAIC STATION

Solar panels have a nonlinear voltage-current characteristic, with a distinct maximum power point (MPP), which depends on the environmental factors, such as temperature and irradiation. In order to continuously harvest maximum power from the solar panels, they have to operate at their MPP despite the inevitable changes in the environment. This is why the controllers of all solar power electronic converters employ some method for maximum power point tracking (MPPT ). Over the past years many MPPT techniques have been published and based on that the main paper’s objective is to analyze one of the most promising MPPT control algorithms: fuzzy logic controller

Characterization of phenylpropanoid pathway genes within European maize (Zea mays L.) inbreds

<p>Abstract</p> <p>Background</p> <p>Forage quality of maize is influenced by both the content and structure of lignins in the cell wall. Biosynthesis of monolignols, constituting the complex structure of lignins, is catalyzed by enzymes in the phenylpropanoid pathway.</p> <p>Results</p> <p>In the present study we have amplified partial genomic fragments of six putative phenylpropanoid pathway genes in a panel of elite European inbred lines of maize (<it>Zea mays </it>L.) contrasting in forage quality traits. Six loci, encoding C4H, 4CL1, 4CL2, C3H, F5H, and CAD, displayed different levels of nucleotide diversity and linkage disequilibrium (LD) possibly reflecting different levels of selection. Associations with forage quality traits were identified for several individual polymorphisms within the <it>4CL1</it>, <it>C3H</it>, and <it>F5H </it>genomic fragments when controlling for both overall population structure and relative kinship. A 1-bp indel in <it>4CL1 </it>was associated with <it>in vitro </it>digestibility of organic matter (IVDOM), a non-synonymous SNP in <it>C3H </it>was associated with IVDOM, and an intron SNP in <it>F5H </it>was associated with neutral detergent fiber. However, the <it>C3H </it>and <it>F5H </it>associations did not remain significant when controlling for multiple testing.</p> <p>Conclusion</p> <p>While the number of lines included in this study limit the power of the association analysis, our results imply that genetic variation for forage quality traits can be mined in phenylpropanoid pathway genes of elite breeding lines of maize.</p

Polymorphisms in monolignol biosynthetic genes are associated with biomass yield and agronomic traits in European maize (Zea mays L.)

<p>Abstract</p> <p>Background</p> <p>Reduced lignin content leads to higher cell wall digestibility and, therefore, better forage quality and increased conversion of lignocellulosic biomass into ethanol. However, reduced lignin content might lead to weaker stalks, lodging, and reduced biomass yield. Genes encoding enzymes involved in cell wall lignification have been shown to influence both cell wall digestibility and yield traits.</p> <p>Results</p> <p>In this study, associations between monolignol biosynthetic genes and plant height (PHT), days to silking (DTS), dry matter content (DMC), and dry matter yield (DMY) were identified by using a panel of 39 European elite maize lines. In total, 10 associations were detected between polymorphisms or tight linkage disequilibrium (LD) groups within the <it>COMT</it>, <it>CCoAOMT2</it>, <it>4CL1</it>, <it>4CL2</it>, <it>F5H</it>, and <it>PAL </it>genomic fragments, respectively, and the above mentioned traits. The phenotypic variation explained by these polymorphisms or tight LD groups ranged from 6% to 25.8% in our line collection. Only <it>4CL1 </it>and <it>F5H </it>were found to have polymorphisms associated with both yield and forage quality related characters. However, no pleiotropic polymorphisms affecting both digestibility of neutral detergent fiber (DNDF), and PHT or DMY were discovered, even under less stringent statistical conditions.</p> <p>Conclusion</p> <p>Due to absence of pleiotropic polymorphisms affecting both forage yield and quality traits, identification of optimal monolignol biosynthetic gene haplotype(s) combining beneficial quantitative trait polymorphism (QTP) alleles for both quality and yield traits appears possible within monolignol biosynthetic genes. This is beneficial to maximize forage and bioethanol yield per unit land area.</p

Polymorphisms in O-methyltransferase genes are associated with stover cell wall digestibility in European maize (Zea mays L.)

<p>Abstract</p> <p>Background</p> <p>OMT (O-methyltransferase) genes are involved in lignin biosynthesis, which relates to stover cell wall digestibility. Reduced lignin content is an important determinant of both forage quality and ethanol conversion efficiency of maize stover.</p> <p>Results</p> <p>Variation in genomic sequences coding for <it>COMT, CCoAOMT1</it>, and <it>CCoAOMT2 </it>was analyzed in relation to stover cell wall digestibility for a panel of 40 European forage maize inbred lines, and re-analyzed for a panel of 34 lines from a published French study. Different methodologies for association analysis were performed and compared. Across association methodologies, a total number of 25, 12, 1, 6 <it>COMT </it>polymorphic sites were significantly associated with DNDF, OMD, NDF, and WSC, respectively. Association analysis for <it>CCoAOMT1 </it>and <it>CCoAOMT2 </it>identified substantially fewer polymorphic sites (3 and 2, respectively) associated with the investigated traits. Our re-analysis on the 34 lines from a published French dataset identified 14 polymorphic sites significantly associated with cell wall digestibility, two of them were consistent with our study. Promising polymorphisms putatively causally associated with variability of cell wall digestibility were inferred from the total number of significantly associated SNPs/Indels.</p> <p>Conclusions</p> <p>Several polymorphic sites for three O-methyltransferase loci were associated with stover cell wall digestibility. All three tested genes seem to be involved in controlling DNDF, in particular <it>COMT</it>. Thus, considerable variation among <it>Bm3 </it>wildtype alleles can be exploited for improving cell-wall digestibility. Target sites for functional markers were identified enabling development of efficient marker-based selection strategies.</p

Diversität- und Assoziationsanalyse von Kandidatengenen für Futterqualität und Blühzeitpunkt bei Mais (Zea mays L.)

The aim of this work was the identification of polymorphisms within candidate genes from the lignin biosynthesis pathway with possible influence on the silage quality of maize. To achieve this goal, partial or complete genomic sequences from up to 40 independent maize inbreds were obtained and analysed using an association mapping approach. Fife of the analysed 8 loci showed polymorphisms with significant association with the variation of some of the measured maize quality criteria. Several polymorphisms were located in the COMT locus, which is known for a naturally occurring mutation resulting in drastic improvement of maize digestibility. Furthermore, the vulnerability of association studies to false positives was assayed using 9 polymorphisms within the Dwarf8 locus, that were genotyped at 71 maize inbreds. The significant correlation of this polymorphisms with flowering time, previously found in a former study, could be only confirmed when the genetically inferred population structure was not considered.Das Hauptziel dieser Arbeit war die Identifizierung von Polymorphismen innerhalb von Kandidatengenen aus dem Ligninbiosyntheseweg mit möglichem Einfluß auf die Qualität von Silomais. Dazu wurden teilweise Komplette genomische Sequenzen aus bis zu 40 unabhängigen Maisinzuchtlinien erhalten und mittels Assoziationskartierung untersucht. Bei 5 der untersuchten 8 Loci konnten polymorphismen gefunden werden, die eine signifikante Korrelation mit der Variation von einigen der gemessenen Qualitätskriteien zeigten, mehrere davon beim COMT einem Gen, bei dem eine natürlich vorkommende Mutation zu drastischer Verbesserung der Verdaulichkeit führt. Weiterhin wurde die Wiederholbarkeit von Assoziationsstudien anhand von 9 polymorphismen des Dwarf8 Lokus aus 71 Maisinzuchtlinien untersucht. Der in einer vorherigen Studie gefundene signifikante Einfluß einiger dieser Polymorphismen auf den Blühzeitpunkt konnte nur im Falle der nicht-Berücksichtigung der Populationsstruktur bestätigt werden

ПРИМЕНЕНИЕ КОНТРОЛЛЕРА НЕЧЕТКОЙ ЛОГИКИ ДЛЯ УПРАВЛЕНИЯ ФОТОЭЛЕКТРИЧЕСКОЙ СТАНЦИЕЙ

Solar panels have a nonlinear voltage-current characteristic, with a distinct maximum power point (MPP), which depends on the environmental factors, such as temperature and irradiation. In order to continuously harvest maximum power from the solar panels, they have to operate at their MPP despite the inevitable changes in the environment. This is why the controllers of all solar power electronic converters employ some method for maximum power point tracking (MPPT ). Over the past years many MPPT techniques have been published and based on that the main paper’s objective is to analyze one of the most promising MPPT control algorithms: fuzzy logic controller. Солнечные батареи (СБ) имеют нелинейные вольт- амперные характеристики с характерной точкой максимальной выходной мощности (МВМ), которая зависит от условий окружающей среды, таких как температура  и уровень солнечного излучения. Для обеспечения максимальной выходной мощности СБ должны работать  в точке МВМ независимо от условий окружающей среды. Эта задача обеспечивается соответствующим контроллером, который целесообразно реализовать на основе нечеткой логики