Maydica special issue - Exploitation of grass cell wall related traits for improving biofuel productions: an overview

Maydica special issue - Exploitation of grass cell wall related traits for improving biofuel productions: an overview

Genetic Strategies to Enhance Plant Biomass Yield and Quality- Related Traits for Bio-Renewable Fuel and Chemical Productions

Owing to the increasing concerns on the environment, climate change, and limited natural resources, there are currently considerable efforts applied to produce chemicals and materials from renewable biomass. While initial emphasis has been placed on biofuel production from food plant sugars, the competition between crop usage for food and non-food applications has promoted research efforts to genetically improve yield and quality-related traits for biorefining applications. This chapter summarizes the potential of genetic and biotechnological strategies for improving plant biomass yields and quality-related traits and for breeding varieties more suitable to meet biorefining applications. Attempts were also made to provide a description on the genetic and molecular mechanisms affecting starch, cell wall composition and architecture, and oils synthesis and deposition, including genetic strategies to modify these traits. Similarly, the chapter covers the genetic strategies to improve yields by emphasizing the efforts done to identifying genetic variation and gene(s) governing critical morphological, structural, and physiological traits that in turn influence biomass yields. Finally, in the chapter it is suggested that knowledge of plant biosynthetic pathways will eventually provide valuable opportunities for metabolic engineering, as well as access to chemical transformations unique to plants for breeding varieties with built-in new traits

Variation of metabolic profiles in developing maize kernels up-and down-regulated for the hda101 gene

Abstract To shed light on the specific contribution of HDA101 in modulating metabolic pathways in the maize seed, changes in the metabolic profiles of kernels obtained from hda101 mutant plants have been investigated by a metabonomic approach. Dynamic properties of chromatin folding can be mediated by enzymes that modify DNA and histones. The enzymes responsible for the steady-state of histone acetylation are histone acetyltransferase and histone deacetylase (HDA). Therefore, it is interesting to evaluate the effects of up-and down-regulation of a Rpd-3 type HDA on the development of maize seeds in terms of metabolic changes. This has been reached by analysing nuclear magnetic resonance spectra by different chemometrician approaches, such as Orthogonal Projection to Latent Structure-Discriminant Analysis, Parallel Factors Analysis, and Multi-way Partial Least SquaresDiscriminant Analysis (N-PLS-DA). In particular, the latter approaches were chosen because they explicitly take time into account, organizing data into a set of slices that refer to different steps of the developing process. The results show the good discriminating capabilities of the N-PLS-DA approach, even if the number of samples ought be increased to obtain better predictive capabilities. However, using this approach, it was possible to show differences in the accumulation of metabolites during development and to highlight the changes occuring in the modified seeds. In particular, the results confirm the role of this gene in cell cycle control

Characterization of the maize b-32 ribosome inactivating protein and its interaction with fungal pathogen development

Plants respond to attack by pathogenic fungi with a complex network of responses, including the production and accumulation of proteins, such as the Ribosome Inactivating Proteins (RIPs) that are toxic or inhibitory to pathogens. In maize endosperm, a cytosolic albumin termed b-32 (RIP1) is synthesized in temporal and quantita¬tive coordination with the deposition of storage proteins. Research has shown that b-32 is able to i) enzymati¬cally inactive ribosomes modifying rRNA inhibiting protein synthesis in vitro, ii) inhibit the growth of Rhizoctonia solani mycelia in an in vitro and in planta assays, iii) reduce Fusarium culmorum head blight in wheat transgenic plants expressing b-32, and iv) diminish Fusarium verticillioides attack symptoms in leaf tissues assays of maize transgenic expressing ectopically b-32 protein. Similarly to other RIPs, maize b-32 is accumulated in the seed as an inactive precursor, which is converted into an active form by proteolytic processing which removes peptide segments from the N (residues 1-16 of pro-RIP) and C (residues 295-301) termini and also from the center (linker domain) of the polypeptide. In this review we will summarize evidence and advances related to the ability of the b-32 protein in contrasting pathogen attacks by considering and describing i) in vivo b-32 antifungal activity and ii) in vitro fungal development inhibition. These data provide information for assessing b-32 in developing plants with a higher capacity to contrast damages induced by pathogens

Assesment of genetic diversity and relationships among maize inbred lines developed in Italy

The genetic diversity pattern of a sample of 144 maize inbred lines comprising 106 Italian entries, considered representative of the breeding material developed at the Bergamo Maize Breeding Station, and a sample of 38, mainly US Corn Belt based, reference lines was accessed using AFLP markers. A total of 811 polymorphic fragments were identified. Exploration of the variation disclosed by the lines by means of principal component analysis (PCA) and hierarchical clustering allowed their division into major heterotic groups. The obtained grouping of the inbred lines reflected pedigree information and resulted in the identification of major clusters derived from Lancaster Sure Crop (LSC), Iowa Stiff Stock Synthetic (BSSS), and miscellaneous heterotic breeding material. AMOVA statistics, performed on the established genetic structure, revealed a high proportion of variance between individuals and among populations stressing the high polymorphic nature of the maize pool analyzed. Regarding population structures, the genetic distance among populations (FST = 0.50 } 0.1) and the degree of inbreeding within groups (FSC = 0.46 } 0.1) did not diverge significantly, while both significantly differed from the degree of relatedness between markers within groups (FCT = 0.06 } 0.04). In conclusion, the results presented indicate that AFLPs are useful in assigning inbred lines to heterotic groups and for superior line development with the aim to maximize heterosis and consequently yield performance

Evaluation of the maize ( Zea mays L.) diversity on the Archipelago of Madeira

Abstract The variability of 43 open-pollinated populations of maize (Zea mays L.), representing a wide range of ecological conditions on the Archipelago of Madeira, was evaluated based on the morphological and reproductive traits. Individual data of 41 traits related to earliness, plant and tassel structure and the shape of the ear and grain were analysed using multivariate analysis. The populations belonging to two major maize varieties were grouped into four groups by their degree of dissimilarity, based on discriminant analysis. The dissimilarity of these groups was confirmed by the values of the Tukey test. The racial rank of these groups was proposed and a brief description of the maize landraces was presented. This work represents the first morphological characterization and analysis of diversity of maize germplasm for the Archipelago of Madeira where the traditional agricultural practices are still keeping this Portuguese region free from corn hybrids. The description of the Madeiran corn landraces allows us to preserve the existing corn biodiversity and could be used for their registration as conservation landraces or for conservation and breeding proposes worldwide

Evaluation of the maize (Zea mays L.) diversity on the Archipelago of Madeira

The variability of 43 open-pollinated populations of maize (Zea mays L.), representing a wide range of ecological conditions on the Archipelago of Madeira, was evaluated based on the morphological and reproductive traits. Individual data of 41 traits related to earliness, plant and tassel structure and the shape of the ear and grain were analysed using multivariate analysis. The populations belonging to two major maize varieties were grouped into four groups by their degree of dissimilarity, based on discriminant analysis. The dissimilarity of these groups was confirmed by the values of the Tukey test. The racial rank of these groups was proposed and a brief description of the maize landraces was presented. This work represents the first morphological characterization and analysis of diversity of maize germplasm for the Archipelago of Madeira where the traditional agricultural practices are still keeping this Portuguese region free from corn hybrids. The description of the Madeiran corn landraces allows us to preserve the existing corn biodiversity and could be used for their registration as conservation landraces or for conservation and breeding proposes worldwide.Portuguese Foundation for the Science and Technology (FCT, Fundac¸a˜o para a Cieˆncia e Tecnologia) has sponsored this work, through the Centre of Macaronesian Studies (CEM) and the project POCTI no35003/AGR/2001. The Authors are grateful to the Madeiran farmers who assisted with collection of maize samples.info:eu-repo/semantics/publishedVersio

Nutritional composition of a selected white food-grade waxy sorghum variety grown in Mediterranean environment

A white food-grade waxy sorghum Tw variety, grown in two Mediterranean sites (named Tw1M and Tw1S) was evaluated for nutrient composition and fatty acid- and mineral concentrations in order to determine the suitability of producing waxy sorghum for human uses in southern Italy. The nutritional values of the grains of the Tw inbred line grown in the two trial fields were substantially the same, except for slight differences in ash level and accordingly slight variation in mineral composition. In samples from both locations, a higher percentage of K was observed among the nutritionally essential macro-elements, and higher percentages of Zn, Fe, Mn, Cu, Al among the nutritionally essential micro-element along with a strong difference in Cd content was among trace elements. Across both sites linoleic, oleic and palmitic were the most abundant fatty acids, while very slight variations in the content of minerals were found among the two samples examined. These results demonstrate the importance of developing agronomically productive waxy sorghum varieties suitable for growth in non-traditional sorghum producing regions both as a food and feed crop (i.e. with good nutritional quality) and for utilization in new products at the industrial level

The Zea mays mutants opaque-2 and opaque-7 disclose extensive changes in endosperm metabolism as revealed by protein, amino acid, and transcriptome-wide analyses

<p>Abstract</p> <p>Background</p> <p>The changes in storage reserve accumulation during maize (<it>Zea mays </it>L.) grain maturation are well established. However, the key molecular determinants controlling carbon flux to the grain and the partitioning of carbon to starch and protein are more elusive. The <it>Opaque-2 </it>(<it>O2</it>) gene, one of the best-characterized plant transcription factors, is a good example of the integration of carbohydrate, amino acid and storage protein metabolisms in maize endosperm development. Evidence also indicates that the <it>Opaque-7 </it>(<it>O7</it>) gene plays a role in affecting endosperm metabolism. The focus of this study was to assess the changes induced by the <it>o2 </it>and <it>o7 </it>mutations on maize endosperm metabolism by evaluating protein and amino acid composition and by transcriptome profiling, in order to investigate the functional interplay between these two genes in single and double mutants.</p> <p>Results</p> <p>We show that the overall amino acid composition of the mutants analyzed appeared similar. Each mutant had a high Lys and reduced Glx and Leu content with respect to wild type. Gene expression profiling, based on a unigene set composed of 7,250 ESTs, allowed us to identify a series of mutant-related down (17.1%) and up-regulated (3.2%) transcripts. Several differentially expressed ESTs homologous to genes encoding enzymes involved in amino acid synthesis, carbon metabolism (TCA cycle and glycolysis), in storage protein and starch metabolism, in gene transcription and translation processes, in signal transduction, and in protein, fatty acid, and lipid synthesis were identified. Our analyses demonstrate that the mutants investigated are pleiotropic and play a critical role in several endosperm-related metabolic processes. Pleiotropic effects were less evident in the <it>o7 </it>mutant, but severe in the <it>o2 </it>and <it>o2o7 </it>backgrounds, with large changes in gene expression patterns, affecting a broad range of kernel-expressed genes.</p> <p>Conclusion</p> <p>Although, by necessity, this paper is descriptive and more work is required to define gene functions and dissect the complex regulation of gene expression, the genes isolated and characterized to date give us an intriguing insight into the mechanisms underlying endosperm metabolism.</p

Variation of metabolic profiles in developing maize kernels up- and down-regulated for the hda101 gene

To shed light on the specific contribution of HDA101 in modulating metabolic pathways in the maize seed, changes in the metabolic profiles of kernels obtained from hda101 mutant plants have been investigated by a metabonomic approach. Dynamic properties of chromatin folding can be mediated by enzymes that modify DNA and histones. The enzymes responsible for the steady-state of histone acetylation are histone acetyltransferase and histone deacetylase (HDA). Therefore, it is interesting to evaluate the effects of up- and down-regulation of a Rpd-3 type HDA on the development of maize seeds in terms of metabolic changes. This has been reached by analysing nuclear magnetic resonance spectra by different chemometrician approaches, such as Orthogonal Projection to Latent Structure-Discriminant Analysis, Parallel Factors Analysis, and Multi-way Partial Least Squares-Discriminant Analysis (N-PLS-DA). In particular, the latter approaches were chosen because they explicitly take time into account, organizing data into a set of slices that refer to different steps of the developing process. The results show the good discriminating capabilities of the N-PLS-DA approach, even if the number of samples ought be increased to obtain better predictive capabilities. However, using this approach, it was possible to show differences in the accumulation of metabolites during development and to highlight the changes occuring in the modified seeds. In particular, the results confirm the role of this gene in cell cycle control