Copy number variation at the HvCBF4–HvCBF2 genomic segment is a major component of frost resistance in barley

A family of CBF transcription factors plays a major role in reconfiguring the plant transcriptome in response to low-freezing temperature in temperate cereals. In barley, more than 13 HvCBF genes map coincident with the major QTL FR-H2 suggesting them as candidates to explain the function of the locus. Variation in copy number (CNV) of specific HvCBFs was assayed in a panel of 41 barley genotypes using RT-qPCR. Taking advantage of an accurate phenotyping that combined Fv/Fm and field survival, resistance-associated variants within FR-H2 were identified. Genotypes with an increased copy number of HvCBF4 and HvCBF2 (at least ten and eight copies, respectively) showed greater frost resistance. A CAPS marker able to distinguish the CBF2A, CBF2B and CBF2A/B forms was developed and showed that all the higher-ranking genotypes in term of resistance harbour only CBF2A, while other resistant winter genotypes harbour also CBF2B, although at a lower CNV. In addition to the major involvement of the HvCBF4-HvCBF2 genomic segment in the proximal cluster of CBF elements, a negative role of HvCBF3 in the distal cluster was identified. Multiple linear regression models taking into account allelic variation at FR-H1/VRN-H1 explained 0.434 and 0.550 (both at p < 0.001) of the phenotypic variation for Fv/Fm and field survival respectively, while no interaction effect between CNV at the HvCBFs and FR-H1/VRN-H1 was found. Altogether our data suggest a major involvement of the CBF genes located in the proximal cluster, with no apparent involvement of the central cluster contrary to what was reported for wheat

TEOSINTE BRANCHED1 regulates height and stem internode length in bread wheat

Regulation of plant height and stem elongation has contributed significantly to improvement of cereal productivity by reducing lodging and improving distribution of assimilates to the inflorescence and grain. In wheat, genetic control of height has been largely contributed by the Reduced height-1 alleles that confer gibberellin insensitivity; the beneficial effects of these alleles are associated with less favourable effects involving seedling emergence, grain quality, and inflorescence architecture that have driven new research investigating genetic variation of stem growth. Here, we show that TEOSINTE BRANCHED1 (TB1) regulates height of wheat, with TB1 being expressed at low levels in nodes of the main culm prior to elongation, and increased dosage of TB1 restricting elongation of stem internodes. The effect of TB1 on stem growth is not accompanied by poor seedling emergence, as transgenic lines with increased activity of TB1 form longer coleoptiles than null transgenic controls. Analysis of height in a multiparent mapping population also showed that allelic variation for TB1 on the B genome influences height, with plants containing the variant TB-B1b allele being taller than those with the wild-type TB-B1a allele. Our results show that TB1 restricts height and stem elongation in wheat, suggesting that variant alleles that alter the expression or function of TB1 could be used as a new source of genetic diversity for optimizing architecture of wheat in breeding programmes

Barley: Omics approaches for abiotic stress tolerance

Abiotic stresses such as frost, drought, salinity, hypoxia, and mineral deficiency or toxicity frequently limit growth and productivity of temperate cereal crops, for which barley (Hordeum vulgare L. ssp. vulgare) could represent a model. Improving barley resistance to such constraints is thus fundamental in view of the expected climate change for minimizing the gap between potential and actual yield (the so-called yield gap), increasing the yield stability, and guaranteeing the sustainability of the crop. As different omics technologies have been developed during the past few decades, they enabled systematic analysis of changes that occur in plants in response to abiotic stresses. In this chapter, we focus on the omics contribution to the improvement of abiotic stress tolerance in barley. After a brief summary of the most relevant abioticstresses that limit the crop yields worldwide, successful genomics approaches have been described, starting from the exploitation of germplasm resources. Structural and functional approaches that helped in understanding the mechanisms and the genetic bases of abiotic stress tolerance, when applied to barley and model species(mainly Arabidopsis, rice, and Brachypodium), have been reviewed as an important step toward crop tolerance improvement. Quantitative genetics and genetical genomics of abiotic stress tolerance have been discussed, as they represent both a huge source of information and a challenge for future holistic approaches. Then, we present an overview of the contribution of other omics sciences (e.g., proteomics, epigenomics, metabolomics, ionomics, and phenomics). In the last section, integrative (systems) biology, together with a series of strategies for the future, is proposed and discussed

Inside the CBF locus in Poaceae

Several molecular evidences have been gathered in Poaceae that point out a central role of the CBF/DREB1 transcription factors in the signal transduction pathways leading to low-temperature tolerance, although to a quite different extent between crops originating from either temperate or tropical climates. A common feature of the CBF/DREB1 genes in Poaceae is their structural organization at the genome level in clusters of tandemly duplicated genes. In temperate cereals such as barley and wheat, expansion of specific multigene phylogenetic clades of CBFs that map at the Frost Resistance-2 locus has been exclusively observed. In addition, copy number variants of CBF genes between frost resistant and frost sensitive genotypes raise the question if multiple copies of the CBF/DREB1s are required to ensure freezing tolerance. On the other hand, in crops of tropical origin such as rice and maize, a smaller or less-responsive CBF regulon may have evolved, and different mechanisms might determine chilling tolerance. In this review, recent advances on the organization and diversity at the CBF cluster locus in the grasses are provided and discussed

Bioetanolo di 2ª generazione da panico verga, novità in Italia

Con produzioni potenziali di 25 t/ha di sostanza secca all’anno per più di 15 anni, bassi input agronomici necessari e l’utilizzo del parco macchine delle colture foraggere, il panico verga fornisce i presupposti per una fi liera corta del bioetanolo di 2ª generazion

Bioetanolo di 2ª generazione da panico verga, novità in Italia

Con produzioni potenziali di 25 t/ha di sostanza secca all’anno per più di 15 anni, bassi input agronomici necessari e l’utilizzo del parco macchine delle colture foraggere, il panico verga fornisce i presupposti per una fi liera corta del bioetanolo di 2ª generazion

Evaluation of Cucurbita pepo germplasm for staminate flower production and adaptation to the frozen food industry

Cucurbita pepo is the most economically important species of the genus Cucurbita (Cucurbitaceae). Its edible-fruited cultivated germplasm has been grouped into eight morphotypes (cultivar-groups) divided between two subspecies: pepo and ovifera. In this work, 93 accessions representative of all morphotypes were grown to investigate their genetic variability and to evaluate their potential for production and suitability of male flowers to be used as an Italian frozen food specialty. Results provid the first indications of a plant ideotype for such use. Principal coordinates analysis (PCoA) with nine SSR markers clearly separated the two subspecies, and yielded information on genetically similar vs distant genotypes to be used for parent choice in breeding programs. Analysis of morphological data allowed identification of seven accessions that met all the criteria for the specialty use of male flowers for the frozen food industry: production of many flowers, corolla length of 6–8 cm; and reduced spininess of the foliage. When accessions representing different morphotypes were compared for average male corolla length and average number of male flowers per plant, some accessions of the Pumpkin cultivar-group were observed to be the most suitable for the purpose. Overall, the information collected in the present work is a starting point for exploitation of C. pepo biodiversity in future breeding programs aimed at the production of male flowers for use by the frozen-food industry

Panicum virgatum (L.) Come Fonte Di Energia Alternativa: Biodiversità E Impiego In Terreni Marginali

Fra le fonti di energia rinnovabili, il bioetanolo rappresenta una interessante alternativa ai combustibili fossili. Poiché la richiesta di questo combustibile è destinata ad aumentare su scala globale, vi è la necessità di produrlo a partire da substrati facilmente reperibili ed a basso costo come i residui lignocellulosici (biocombustibili di seconda generazione). Alcuni dubbi sussistono ancora relativamente a quale possa essere la coltura migliore per la produzione di biomassa destinata alla generazione di bioetanolo; un’interessante alternativa ai cereali coltivati ad elevati input quali il mais è rappresentata dalla erbacea perenne Panicum virgatum L. (o "switchgrass" o panico verga). E' interessante valutarne la reale adattabilità in aree marginali, e al clima Italiano. In aggiunta, ci si attende che la produttività di Panicum virgatum non si discosti significativamente da quella di Arundo donax, mentre il costo di impianto della prima specie risulta nettamente inferiore a quello della seconda. Questo lavoro è stato realizzato grazie al progetto "Enerpan", finanziato dal MiPAF. E' stato nostro obiettivo valutare la vocazione di tale specie alla coltivazione in un’area marginale sabbiosa del Nord Italia, oltre alla creazione di una collezione di germoplasma di Panicum virgatum, e alla sua caratterizzazione in termini di biodiversità morfo-fisiologica e molecolar