Luigi Cattivelli

Two loci on chromosome 5H determine low-temperature tolerance in a ‘Nure’ (winter) × ‘Tremois’ (spring) barley map

Barley (Hordeum vulgare subsp. vulgare) is an economically important diploid model for the Triticeae; and a better understanding of low-temperature tolerance mechanisms could significantly improve the yield of fall-sown cereals. We developed a new resource for genetic analysis of winter hardiness-related traits, the ‘Nure’ × ‘Tremois’ linkage map, based on a doubled-haploid population that is segregating for low-temperature tolerance and vernalization requirement. Three measures of low-temperature tolerance and one measure of vernalization requirement were used and, for all traits, QTLs were mapped on chromosome 5H. The vernalization response QTL coincides with previous reports at the Vrn-1/Fr1 region of the Triticeae. We also found coincident QTLs at this position for all measures of low-temperature tolerance. Using Composite Interval Mapping, a second proximal set, of coincident QTLs for low-temperature tolerance, and the accumulation of two different COR proteins (COR14b and TMC-Ap3) was identified. The HvCBF4 locus, or another member of the CBF loci clustered in this region, is the candidate gene underlying this QTL. There is a CRT/DRE recognition site in the promoter of cor14b with which a CBF protein could interact. These results support the hypothesis that highly conserved regulatory factors, such as members of the CBF gene family, may regulate the stress responses of a wide range of plant species.

Relationships between grain protein content and grain yield components through quantitative trait locus analyses in a recombinant inbred line population derived from two elite durum wheat cultivars

Grain protein content (GPC) in durum wheat (Triticum turgidum var. durum) is negatively correlated with grain yield. To evaluate possible genetic interrelationships between GPC and grain yield per spike, thousand-kernel weight and kernel number per spike, quantitative trait loci (QTL) for GPC were mapped using GPC-adjusted data in a covariance analysis on yield components. Phenotypic data were evaluated in a segregating population of 120 recombinant inbred lines derived from crossing the elite cultivars Svevo and Ciccio. The material was tested at five environments in southern Italy. QTL were determined by composite interval mapping based on the Svevoxa0×xa0Ciccio linkage map described in Gadaleta et al. (2009) and integrated with DArT markers. The close relationship between GPC and yield components was reflected in the negative correlation between the traits and in the reduction of variance when GPC values were adjusted to yield components. Ten independent genomic regions involved in the expression of GPC were detected, six of which were associated with QTL for one or more grain yield components. QTL alleles with increased GPC effects were associated with QTL alleles with decreased effects on one or more yield component traits, or vice versa (i.e. the allelic effects were in opposite direction). Four QTL for GPC showed always significant effects, and these QTL should represent genes that influence GPC independently from variation in the yield components. Such genes are of special interest in wheat breeding since they would allow an increase in GPC without a concomitant decrease in grain yield.

Genetic analysis of the accumulation of COR14 proteins in wild (Hordeum spontaneum) and cultivated (Hordeum vulgare) barley

The cold-regulated (COR14) protein of 14 kDa is a polypeptide accumulated under low-temperature conditions in the chloroplasts of barley leaves. In H. vulgare the COR14 antibody cross-reacts with two proteins, with a slightly different relative molecular weight around the marker of 14.4 kDa, referred to as COR14a and COR14b (high and low relative molecular weight, respectively). In a collection of H. spontaneum genotypes a clear polymorphism was found for the corresponding COR proteins. While some accessions showed the same COR pattern as cultivated barley, in 38 out of 61 accessions examined the COR14 antibody cross-reacted with an additional coldregulated protein with a relative molecular weight of about 24 kDa (COR24). The accumulation of COR24 was often associated with the absence of COR14b; the relationship between the COR14b/COR24 polymorphism and the adaptation of H. spontaneum to different environments is discussed. By studying COR14 accumulation in cultivated barley we have found that the threshold induction-temperature of COR14a is associated with the loci controlling winter hardiness. This association was demonstrated by using either a set of 30 cultivars of different origin, or two sets of frost-tolerant and frost-sensitive F1 doubled-haploid lines derived from the cross Dicktoo (winter type) x Morex (spring type). These results suggest that the threshold induction-temperature of COR14a can be a potential biochemical marker for the identification of superior frostresistant barley genotypes.

Physical Mapping of Bread Wheat Chromosome 5A: An Integrated Approach

The huge size, redundancy, and highly repetitive nature of the bread wheat [Triticum aestivum (L.)] genome, makes it among the most difficult species to be sequenced. To overcome these limitations, a strategy based on the separation of individual chromosomes or chromosome arms and the subsequent production of physical maps was established within the frame of the International Wheat Genome Sequence Consortium (IWGSC). A total of 95,812 bacterial artificial chromosome (BAC) clones of short‐arm chromosome 5A (5AS) and long‐arm chromosome 5A (5AL) arm‐specific BAC libraries were fingerprinted and assembled into contigs by complementary analytical approaches based on the FingerPrinted Contig (FPC) and Linear Topological Contig (LTC) tools. Combined anchoring approaches based on polymerase chain reaction (PCR) marker screening, microarray, and sequence homology searches applied to several genomic tools (i.e., genetic maps, deletion bin map, neighbor maps, BAC end sequences (BESs), genome zipper, and chromosome survey sequences) allowed the development of a high‐quality physical map with an anchored physical coverage of 75% for 5AS and 53% for 5AL with high portions (64 and 48%, respectively) of contigs ordered along the chromosome. In the genome of grasses, Brachypodium [Brachypodium distachyon (L.) Beauv.], rice (Oryza sativa L.), and sorghum [Sorghum bicolor (L.) Moench] homologs of genes on wheat chromosome 5A were separated into syntenic blocks on different chromosomes as a result of translocations and inversions during evolution. The physical map presented represents an essential resource for fine genetic mapping and map‐based cloning of agronomically relevant traits and a reference for the 5A sequencing projects.

Agronomic and qualitative traits of T. turgidum ssp. dicoccum genotypes cultivated in Italy

SummaryThe increasing popularity of organic agriculture and health food products has led to a renewed interest in hulled wheat species such as emmer (Triticum turgidum ssp. dicoccumSchubler). Knowledge on agronomic and quality traits is required for effective and efficient use of germplasm collections in breeding programs. The objective of this study was to estimate agronomic and grain quality traits of emmer wheat cultivated in Italy. A total of 20 emmer accessions consisting of landraces, breeding lines or cultivars selected from landraces and modern cultivars were examined under low input conditions. The study was conducted for three successive years (2002–2004) at one location of Southern Italy (Foggia). The entries were characterized for agronomic and qualitative traits [grain yield (t ha−1), thousand grain weight (g), test weight (kg hl−1), grain protein content (%), HMWG composition, dry gluten content (%), gluten index and yellow index, alveograph indices and Total Organic Matter (TOM) on cooked pasta]. The results showed a large genetic variability for most of the traits measured and, even if most of the accessions showed inferior bread- and pasta-making performance, modern cultivars exhibited improved quality traits with some potential to perform healthy and tasty food.

Genome-Wide Association Study for Traits Related to Plant and Grain Morphology, and Root Architecture in Temperate Rice Accessions

Background In this study we carried out a genome-wide association analysis for plant and grain morphology and root architecture in a unique panel of temperate rice accessions adapted to European pedo-climatic conditions. This is the first study to assess the association of selected phenotypic traits to specific genomic regions in the narrow genetic pool of temperate japonica. A set of 391 rice accessions were GBS-genotyped yielding—after data editing—57000 polymorphic and informative SNPS, among which 54% were in genic regions. Results In total, 42 significant genotype-phenotype associations were detected: 21 for plant morphology traits, 11 for grain quality traits, 10 for root architecture traits. The FDR of detected associations ranged from 3 · 10−7 to 0.92 (median: 0.25). In most cases, the significant detected associations co-localised with QTLs and candidate genes controlling the phenotypic variation of single or multiple traits. The most significant associations were those for flag leaf width on chromosome 4 (FDR = 3 · 10−7) and for plant height on chromosome 6 (FDR = 0.011). Conclusions We demonstrate the effectiveness and resolution of the developed platform for high-throughput phenotyping, genotyping and GWAS in detecting major QTLs for relevant traits in rice. We identified strong associations that may be used for selection in temperate irrigated rice breeding: e.g. associations for flag leaf width, plant height, root volume and length, grain length, grain width and their ratio. Our findings pave the way to successfully exploit the narrow genetic pool of European temperate rice and to pinpoint the most relevant genetic components contributing to the adaptability and high yield of this germplasm. The generated data could be of direct use in genomic-assisted breeding strategies.

Flavonoids and Melanins: A Common Strategy across Two Kingdoms

Ultraviolet (UV) radiations alter a number of metabolic functions in vivant. They produce damages to lipids, nucleic acids and proteins, generating reactive oxygen species such as singlet oxygen (O2), hydroxyl radical (HO) and superoxide anion (O2-). Plants and animals, after their water emersion, have developed biochemical mechanisms to protect themselves from that environmental threat through a common strategy. Melanins in animals and flavonoids in plants are antioxidant pigments acting as free radical scavenging mechanisms. Both are phenol compounds constitutively synthesized and enhanced after exposure to UV rays, often conferring a red-brown-dark tissue pigmentation. Noteworthy, beside anti-oxidant scavenging activity, melanins and flavonoids have acquired secondary functions that, both in plants and animals, concern reproductions and fitness. Plants highly pigmented are more resistant to biotic and abiotic stresses. Darker wild vertebrates are generally more aggressive, sexually active and resistant to stress than lighter individuals. Flavonoids have been associated with signal attraction between flowers and insects and with plant-plant interaction. Melanin pigmentation has been proposed as trait in bird communication, acting as honest signals of quality. This review shows how the molecular mechanisms leading to tissue pigmentation have many functional analogies between plants and animals and how their origin lies in simpler organisms such as Cyanobacteria. Comparative studies between plant and animal kingdoms can reveal new insight of the antioxidant strategies in vivant.

Photoperiod-H1 (Ppd-H1) Controls Leaf Size

Photoperiod-H1 controls leaf size by influencing the duration of leaf growth in barley. Leaf size is a major determinant of plant photosynthetic activity and biomass; however, it is poorly understood how leaf size is genetically controlled in cereal crop plants like barley (Hordeum vulgare). We conducted a genome-wide association scan for flowering time, leaf width, and leaf length in a diverse panel of European winter cultivars grown in the field and genotyped with a single-nucleotide polymorphism array. The genome-wide association scan identified PHOTOPERIOD-H1 (Ppd-H1) as a candidate gene underlying the major quantitative trait loci for flowering time and leaf size in the barley population. Microscopic phenotyping of three independent introgression lines confirmed the effect of Ppd-H1 on leaf size. Differences in the duration of leaf growth and consequent variation in leaf cell number were responsible for the leaf size differences between the Ppd-H1 variants. The Ppd-H1-dependent induction of the BARLEY MADS BOX genes BM3 and BM8 in the leaf correlated with reductions in leaf size and leaf number. Our results indicate that leaf size is controlled by the Ppd-H1- and photoperiod-dependent progression of plant development. The coordination of leaf growth with flowering may be part of a reproductive strategy to optimize resource allocation to the developing inflorescences and seeds.

The nuclear-cytoplasmic interaction controls carotenoid content in wheat

In greenhouse studies of three alloplasmic wheat series, plant height, flowering date and yield per plant were least affected when the native cytoplasm was replaced by donor cytoplasm of the Triticum–Aegilops complex than when replaced by Hordeum chilense cytoplasm. On the other hand, significant differences for seed lutein content were found between euplasmic controls and their respective alloplasmic lines in all the alloplasmic lines studied, underscoring the important role of the cytoplasm to determine the seed carotenoid content. Both T. aestivum subesp. macha and Ae. squarrosa cytoplasms increased the lutein content. They may be the most useful sources of cytoplasmic variability for broadening the genetic diversity of wheat for seed carotenoid content since both cytoplasm types do not produce any detrimental effect on agronomic traits, as previously reported by other researchers. These findings demonstrate the role of the nuclearxa0×xa0cytoplasm interaction in the accumulation of carotenoids in wheat.

Evaluation of Genotype Diversity in Oat Germplasm and Definition of Ideotypes Adapted to the Mediterranean Environment

Oat (Avena sativa L.) is a cereal species widely used for human food and livestock feed. It is rich in primary metabolites (e.g., protein, carbohydrate, and fibre) as well as in many secondary compounds (e.g., fructo-oligosaccharides). A germplasm evaluation was carried out to determine the genetic diversity, using univariate and multivariate analyses, and to define an oat ideotype for grain and fodder production adapted to the Mediterranean environment. A total of 109 genotypes were studied under field conditions in Foggia (southern Italy) over two growing seasons (2008-2009 and 2009-2010). All of the accessions were characterised according to 13 bioagronomic traits. Accessions were very different for these evaluated traits, with wide variabilities found particularly for seed yield and fructo-oligosaccharide concentration (CV = 37%). Principal component analysis showed that the first six axes accounted for 81% of the variability. Productivity characteristics and heading time were the major sources of diversity among these oat populations. Clustering entries identified nine groups based on their morphological and agronomic properties. The relationships found among traits can help to determine which groups of genotypes are better adapted to specific environmental conditions and to identify ideotypes for developing varieties for different purposes such as for food or forage.