18 research outputs found
Characterization of the Resistance to Powdery Mildew and Leaf Rust Carried by the Bread Wheat Cultivar Victo
Leaf rust and powdery mildew are two important foliar diseases in wheat. A recombinant inbred line (RIL) population, obtained by crossing two bread wheat cultivars ('Victo' and 'Spada'), was evaluated for resistance to the two pathogens at seedling stage. Upon developing a genetic map of 8726 SNP loci, linkage analysis identified three resistance Quantitative Trait Loci (QTLs), with 'Victo' contributing the resistant alleles to all loci. One major QTL (QPm.gb-7A) was detected in response to Blumeria graminis on chromosome 7A, which explained 90% of phenotypic variation (PV). The co-positional relationship with known powdery mildew (Pm) resistance loci suggested that a new source of resistance was identified in T. aestivum. Two QTLs were detected in response to Puccinia triticina: a major gene on chromosome 5D (QLr.gb-5D), explaining a total PV of about 59%, and a minor QTL on chromosome 2B (QLr.gb-2B). A positional relationship was observed between the QLr.gb-5D with the known Lr1 gene, but polymorphisms were found between the cloned Lr1 and the corresponding 'Victo' allele, suggesting that QLr.gb-5D could represent a new functional Lr1 allele. Lastly, upon anchoring the QTL on the T. aestivum reference genome, candidate genes were hypothesized on the basis of gene annotation and in silico gene expression analysis
Effects of water management and cultivar on carbon dynamics, plant productivity and biomass allocation in European rice systems
We thank the researchers at CREA-Centro di ricerca cerealicoltura e colture industriali, Vercelli, for allowing us to use their facilities, and the technical staff for their assistance. This research was conducted in the framework of the FACCE-JPI project GreenRice (Sustainable and environmental friendly rice cultivation systems in Europe) and was supported by the Biotechnology and Biological Sciences Research Council (BBSRC) BB/M018415/1.Peer reviewedPublisher PD
Physiological Responses to Salt Stress at the Seedling Stage in Wild (Oryza rufipogon Griff.) and Cultivated (Oryza sativa L.) Rice
Domesticated rice Oryza sativa L. is a major staple food worldwide, and the cereal most
sensitive to salinity. It originated from the wild ancestor Oryza rufipogon Griff., which was reported to
possess superior salinity tolerance. Here, we examined the morpho-physiological responses to salinity
stress (80 mM NaCl for 7 days) in seedlings of an O. rufipogon accession and two Italian O. sativa
genotypes, Baldo (mildly tolerant) and Vialone Nano (sensitive). Under salt treatment, O. rufipogon
showed the highest percentage of plants with no to moderate stress symptoms, displaying an
unchanged shoot/root biomass ratio, the highest Na+ accumulation in roots, the lowest root and
leaf Na+/K+ ratio, and highest leaf relative water content, leading to a better preservation of the
plant architecture, ion homeostasis, and water status. Moreover, O. rufipogon preserved the overall
leaf carbon to nitrogen balance and photosynthetic apparatus integrity. Conversely, Vialone Nano
showed the lowest percentage of plants surviving after treatment, and displayed a higher reduction
in the growth of shoots rather than roots, with leaves compromised in water and ionic balance,
negatively affecting the photosynthetic performance (lowest performance index by JIP-test) and
apparatus integrity. Baldo showed intermediate salt tolerance. Being O. rufipogon interfertile with
O. sativa, it resulted a good candidate for pre-breeding towards salt-tolerant lines
Editorial: Disease and pest resistance in rice
Peer reviewe
Markers assisted selection in crop plants. Review Article
Genetic mapping of major genes and quantitative traits loci (QTLs) for many important agricultural traits is increasing the integration of biotechnology with the conventional breeding process. Exploitation of the information derived from the map position of traits with agronomical importance and of the linkedmolecular markers, can be achieved through marker assisted selection (MAS) of the traits during the breeding process. However, empirical applications of this procedure have shown that the success of MAS depends upon several factors, including the genetic base of the trait, the degree of the association between the molecular marker and the target gene, the number of individuals that can be analyzed and the genetic background in which the target gene has to be transferred. MAS for simply inherited traits is gaining increasing importance in breeding programs, allowing an acceleration of the breeding process. Traitsrelated to disease resistance to pathogens and to the quality of some crop products are offering some important examples of a possible routinary application of MAS. For more complex traits, like yield and abiotic stress tolerance, a number of constraints have determined severe limitations on an efficient utilizationof MAS in plant breeding, even if there are a few successful applications in improving quantitative traits. Recent advances in genotyping technologies together with comparative and functional genomic approaches are providing useful tools for the selection of genotypes with superior agronomical performancies
The PCR-Based Marker MWG2018 Linked to the RDG2A Leaf Stripe Resistance Gene Is a Useful Tool for Assessing Barley Resistance in Breeding Programs
Leaf stripe, caused by the fungus Pyrenophora graminea [anamorph Drechslera graminea (Rabenh. ex. Schlech.) Shoemaker], is an important seed-borne disease of barley. The objective of this study was to verify the reliability of a PCR-based marker (MWG2018) associated with the resistance gene Rdg2a and to assess the leaf stripe resistant phenotype in barley breeding programs. A large number of barley cultivars and accessions were thus evaluated for their reaction to a highly virulent monoconidial isolate (Dg2) of the pathogen and genotyped for the allele of the molecular marker. Several resistant genotypes were identified and four were shown to possess the same allele as the cultivar Thibaut (the resistant parent of the original mapping population in which Rdg2a was identified) at the marker locus. One of them, cv. Rebelle, is being used as a source of leaf stripe resistance in winter barley breeding programs. The allelic composition at the MWG2018 locus was verified in several resistant lines bred from five crosses, in which Rebelle acted directly or indirectly as donor of the resistance. The results showed that the resistant phenotype of the lines was always associated with the resistance allele of the molecular marker, thereby demonstrating its reliability for selecting leaf stripe resistance. The MWG2018 PCR-based marker can therefore be proposed as a tool to assess the resistant phenotyp
The rice foot rot pathogen Dickeya zeae alters the in-field plant microbiome
Studies on bacterial plant diseases have thus far
been focused on the single bacterial species causing
the disease, with very little attention given to the
many other microorganisms present in the microbiome.
This study intends to use pathobiome analysis
of the rice foot rot disease, caused by Dickeya
zeae, as a case study to investigate the effects of this
bacterial pathogen to the total resident microbiome
and to highlight possible interactions between the
pathogen and the members of the community
involved in the disease process. The microbiome of
asymptomatic and the pathobiome of foot-rot symptomatic
field-grown rice plants over two growing
periods and belonging to two rice cultivars were
determined via 16S rRNA gene amplicon sequencing.
Results showed that the presence of D. zeae is associated
with an alteration of the resident bacterial
community in terms of species composition, abundance
and richness, leading to the formation of
microbial consortia linked to the disease state. Several
bacterial species were significantly co-presented
with the pathogen in the two growing periods
suggesting that they could be involved in the disease
process. Besides, culture-dependent isolation and in
planta inoculation studies of a bacterial member of
the pathobiome, identified as positive correlated with
the pathogen in our in silico analysis, indicated that it
benefits from the presence of D. zeae. A similar
microbiome/pathobiome experiment was also performed
in a symptomatically different rice disease
evidencing that not all plant diseases have the same
consequence/relationship with the plant microbiome.
This study moves away from a pathogen-focused
stance and goes towards a more ecological perception
considering the effect of the entire microbial
community which could be involved in the pathogenesis,
persistence, transmission and evolution of plant
pathogens