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

Genetic architecture of plant height in maize phenotype-selected introgression families

This study aimed at developing, characterizing and evaluating two maize phenotypic-selected introgression libraries for a collection of dominant plant height (PHT)-increasing alleles by introgressing donor chromosome segments (DCS) from Germplasm Enhancement of Maize (GEM) accessions into elite inbred lines: PHB47 and PHZ51. Different backcross generations (BC1-BC4) were developed and the tallest 23 phenotype-selected introgression families (PIFs) from each introgression library (PHB47 or PHZ51) were selected for single nucleotide polymorphism genotyping to localize DCS underlying PHT. The result shows that most PIFs carrying DCS were significantly (α = 0.01) taller than the respective recurrent parent. In addition, they contained larger donor genome proportions than expected in the absence of selection or random mating across all BC generations. The DCS were distributed over the whole genome, indicating a complex genetic nature underlying PHT. We conclude that our PIFs are enriched for favourable PHT-increasing alleles. These two libraries offer opportunities for future PHT gene isolation and allele characterization and for breeding purposes, such as novel cultivars for biofuel production

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

Genetcis of naked grain distribution in panicles of hexaploids OATS (Avena sativa L.)

A principal característica que diferencia a aveia nuda da aveia com casca é a separação da casca durante o processo de trilha. A expressão incompleta do caráter nuda é um dos entraves à utilização comercial da aveia nuda. Os objetivos deste estudo foram: (i) analisar a expressão do caráter nuda nas panículas dos genitores e da população segregante nas gerações F2 e F3, (ii) estimar o número de genes desse caráter, (iii) analisar possíveis diferenças na expressão do caráter quando utilizadas sementes com e sem casca na semeadura, (iv) determinar a associação do caráter nuda aos caracteres estatura e florescimento. O trabalho foi conduzido na Estação Experimental Agronômica da UFRGS, nos anos 2005 e 2006. Foram utilizados como genitores as linhagens UFRGS 995080-1 (nuda) e UFRGS 970486-3 (com casca), que foram avaliados conjuntamente com a população segregante quanto a presença e distribuição dos grãos sem casca na panícula. O caráter nuda em aveia é governado por um gene dominante de grande efeito sobre o fenótipo, formando três classes fenotípicas distintas na geração F2, nuda, mosaico e com casca, nas proporções 1:2:1, respectivamente. A expressão do caráter nuda nem sempre foi completa nas panículas, mesmo em genótipos homozigotos para a característica, sendo que a menor expressão do caráter nas panículas ocorreu em ramificações de segunda e terceira ordem, localizadas na base destas. Não foram verificadas diferenças nas proporções fenotípicas observadas nas gerações F2 e F3 quando as sementes provenientes de plantas individuais foram separadas em sementes nuda e com casca. Assim como o caráter nuda, a característica multiflora das espiguetas possui herança monogênica, sendo que os dois caracteres são fortemente ligados. Não houve associação do caráter nuda com a estatura da planta e nem com o número de dias para o florescimento. A seleção de fenótipos que formam apenas grãos sem casca ao longo da panícula facilitará o desenvolvimento de novas variedades de aveia nuda, uma vez que são homozigotos e provavelmente apresentarão uma expressão mais estável desta característica.The major difference between naked and conventional oats is the capacity of dehulling during threshing. The incomplete expression of the naked trait limits the commercial exploitation of naked oats. The objectives of this work were: (i) to analyze the expression of the naked trait in panicles of F2 and F3 segregating populations and the parental genotypes, (ii) to estimate the number of genes controlling this trait, (iii) to evaluate if there are any differences in the expression of the naked character, due to the type of seeds, naked or husked, used, (iv) to determine the association of the naked character with plant height and flowering date. This work was conduced at the Agronomic Experimental Station of UFRGS, in 2005 and 2006. The inbred lines used as parents, UFRGS 995080-1 (naked) and UFRGS 970486-3 (hulled), and the segregating populations F2 and F3 were evaluated for the presence and distribution of the naked grains within the panicles. The naked trait is controlled by one dominant major gene. In the F2 generation three phenotypic classes were observed, naked, mosaic, and hulled, in the proportion of 1:2:1, respectively. The expression of the naked trait was incomplete, even for the dominant homozygous genotypes, as confirmed by the F3 analysis. The expression of the naked character was less evident in the second and third order branches, located mostly at the base of the panicle. There were no differences in the phenotypic proportions observed in the F2 and F3 generations based on the type of seed used, i.e, naked or hulled seeds. The multiflorous trait was also monogenic and strongly linked to naked character. There was no association between the naked trait with plant height and flowering date. Selection of phenotypes that express only dehulled seeds throughout the panicle will facilitate the development of new naked oat varieties, since they are homozygous and will probably have a more stable expression of this characteristic

Genetcis of naked grain distribution in panicles of hexaploids OATS (Avena sativa L.)

A principal característica que diferencia a aveia nuda da aveia com casca é a separação da casca durante o processo de trilha. A expressão incompleta do caráter nuda é um dos entraves à utilização comercial da aveia nuda. Os objetivos deste estudo foram: (i) analisar a expressão do caráter nuda nas panículas dos genitores e da população segregante nas gerações F2 e F3, (ii) estimar o número de genes desse caráter, (iii) analisar possíveis diferenças na expressão do caráter quando utilizadas sementes com e sem casca na semeadura, (iv) determinar a associação do caráter nuda aos caracteres estatura e florescimento. O trabalho foi conduzido na Estação Experimental Agronômica da UFRGS, nos anos 2005 e 2006. Foram utilizados como genitores as linhagens UFRGS 995080-1 (nuda) e UFRGS 970486-3 (com casca), que foram avaliados conjuntamente com a população segregante quanto a presença e distribuição dos grãos sem casca na panícula. O caráter nuda em aveia é governado por um gene dominante de grande efeito sobre o fenótipo, formando três classes fenotípicas distintas na geração F2, nuda, mosaico e com casca, nas proporções 1:2:1, respectivamente. A expressão do caráter nuda nem sempre foi completa nas panículas, mesmo em genótipos homozigotos para a característica, sendo que a menor expressão do caráter nas panículas ocorreu em ramificações de segunda e terceira ordem, localizadas na base destas. Não foram verificadas diferenças nas proporções fenotípicas observadas nas gerações F2 e F3 quando as sementes provenientes de plantas individuais foram separadas em sementes nuda e com casca. Assim como o caráter nuda, a característica multiflora das espiguetas possui herança monogênica, sendo que os dois caracteres são fortemente ligados. Não houve associação do caráter nuda com a estatura da planta e nem com o número de dias para o florescimento. A seleção de fenótipos que formam apenas grãos sem casca ao longo da panícula facilitará o desenvolvimento de novas variedades de aveia nuda, uma vez que são homozigotos e provavelmente apresentarão uma expressão mais estável desta característica.The major difference between naked and conventional oats is the capacity of dehulling during threshing. The incomplete expression of the naked trait limits the commercial exploitation of naked oats. The objectives of this work were: (i) to analyze the expression of the naked trait in panicles of F2 and F3 segregating populations and the parental genotypes, (ii) to estimate the number of genes controlling this trait, (iii) to evaluate if there are any differences in the expression of the naked character, due to the type of seeds, naked or husked, used, (iv) to determine the association of the naked character with plant height and flowering date. This work was conduced at the Agronomic Experimental Station of UFRGS, in 2005 and 2006. The inbred lines used as parents, UFRGS 995080-1 (naked) and UFRGS 970486-3 (hulled), and the segregating populations F2 and F3 were evaluated for the presence and distribution of the naked grains within the panicles. The naked trait is controlled by one dominant major gene. In the F2 generation three phenotypic classes were observed, naked, mosaic, and hulled, in the proportion of 1:2:1, respectively. The expression of the naked trait was incomplete, even for the dominant homozygous genotypes, as confirmed by the F3 analysis. The expression of the naked character was less evident in the second and third order branches, located mostly at the base of the panicle. There were no differences in the phenotypic proportions observed in the F2 and F3 generations based on the type of seed used, i.e, naked or hulled seeds. The multiflorous trait was also monogenic and strongly linked to naked character. There was no association between the naked trait with plant height and flowering date. Selection of phenotypes that express only dehulled seeds throughout the panicle will facilitate the development of new naked oat varieties, since they are homozygous and will probably have a more stable expression of this characteristic

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

Background 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. Results 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 COMT, CCoAOMT2, 4CL1, 4CL2, F5H, and PAL 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 4CL1 and F5H 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. Conclusion 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.This article is published as Chen, Yongsheng, Imad Zein, Everton Alen Brenner, Jeppe Reitan Andersen, Mathias Landbeck, Milena Ouzunova, and Thomas Lübberstedt. "Polymorphisms in monolignol biosynthetic genes are associated with biomass yield and agronomic traits in European maize (Zea mays L.)." BMC plant biology 10, no. 1 (2010): 12. doi: 10.1186/1471-2229-10-12. Posted with permission.</p

Maize hybrid X03H001

A novel maize variety designated X03H001 and seed, plants and plant parts thereof are produced by crossing inbred maize varieties. Methods for producing a maize plant by crossing hybrid maize variety X03H001 with another maize plant are disclosed. Methods for producing a maize plant containing in its genetic material one or more traits introgressed into X03H001 through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced thereby. This invention relates to the maize variety X03H001, the seed, the plant produced from the seed, and variants, mutants, and minor modifications of maize variety X03H001. This invention further relates to methods for producing maize varieties derived from maize variety X03H001