Effects of water deficit on leaves and fruit quality during the development period in tomato plant.

In nature, plants are often exposed to a multitude of environmental constraints that severely limit crop productivity. Water deficit is one of the factors that most affects agricultural production. The aim of this work is to evaluate the effect of water deficit on morphology, development, nutritional behavior, as well as chlorophyll fluorescence and certain important metabolic parameters (soluble sugars, organic acids, starch, carotenoid, and vitamin C) of the cultivated tomato ( cv Plovdiv).

Juvenile Coffee Leaves Acclimated to Low Light Are Unable to Cope with a Moderate Light Increase.

The understorey origin of coffee trees and the strong plasticity of leaves in relation to contrasting light environments have been largely shown. The adaptability of coffee leaves to changes in light was tested under controlled conditions by increasing the illumination rate on var. Naryelis seedlings acclimated to low light conditions and observing leaf responses at three different developmental stages (juvenile, growing and mature).

Using a Structural Root System Model to Evaluate and Improve the Accuracy of Root Image Analysis Pipelines.

Root system analysis is a complex task, often performed with fully automated image analysis pipelines. However, the outcome is rarely verified by ground-truth data, which might lead to underestimated biases. We have used a root model, ArchiSimple, to create a large and diverse library of ground-truth root system images (10,000).

A User's View of the Parameters Derived from the Induction Curves of Maximal Chlorophyll Fluorescence: Perspectives for Analyzing Stress.

Analysis of the fast kinetics of the induction curve of maximal fluorescence represents a relatively recent development for chlorophyll fluorescence measurements. The parameters of the so-called JIP-test are exploited by an increasingly large community of users to assess plant stress and its consequences. We provide here evidence that these parameters are capable to distinguish between stresses of different natures or intensities, and between stressed plants of different genetic background or at different developmental stages at the time of stress.

Water deficit effects on tomato quality depend on fruit developmental stage and genotype.

Many studies have advocated that water deficit (WD) may exert beneficial effects on fruit quality. However, the fruit response to WD at specific developmental stages was seldom investigated, although different mechanisms could be involved at each stage and lead to different effects on final fruit quality. In the present study, a moderate WD (-60% of water supply compared to control) was applied during each of the three major phases of fruit development, namely cell division (CD), cell expansion (CE) and maturation (MT).

Towards the Identification of Type III Effectors Associated with Ralstonia solanacearum Virulence on Tomato and Eggplant.

For the development of pathogen-informed breeding strategies, identifying the microbial genes involved in interactions with the plant is a critical step. To identify type III effector (T3E) repertoires associated with virulence of the bacterial wilt pathogen Ralstonia solanacearum on Solanaceous crops, we used an original association genetics approach combining DNA microarray data and pathogenicity data on resistant eggplant, pepper, and tomato accessions. From this first screen, 25 T3Es were further full-length polymerase chain reaction-amplified within a 35-strain field collection, to assess their distribution and allelic diversity.

Genome-Enabled Phylogeographic Investigation of the Quarantine Pathogen Ralstonia solanacearum Race 3 Biovar 2 and Screening for Sources of Resistance Against Its Core Effectors.

Phylogeographic studies inform about routes of pathogen dissemination and are instrumental for improving import/export controls. Genomes of 17 isolates of the bacterial wilt and potato brown rot pathogen Ralstonia solanacearum race 3 biovar 2 (R3bv2), a Select Agent in the United States, were thus analyzed to get insight into the phylogeography of this pathogen. Thirteen of fourteen isolates from Europe, Africa, and Asia were found to belong to a single clonal lineage while isolates from South America were genetically diverse and tended to carry ancestral alleles at the analyzed genomic loci consistent with a South American origin of R3bv2.

Water shortage and quality of fleshy fruits--making the most of the unavoidable.

Extreme climatic events, including drought, are predicted to increase in intensity, frequency, and geographic extent as a consequence of global climate change. In general, to grow crops successfully in the future, growers will need to adapt to less available water and to take better advantage of the positive effects of drought. Fortunately, there are positive effects associated with drought.

Links between root developmental traits and foraging performance.

We designed a simple dynamic and stochastic architectural model with six parameters to link the foraging performance of root systems to their developmental processes. Soil foraging was quantified by the volume enveloping the roots until a given uptake distance. Many simulated architectures were obtained by combining four different values for each parameter.

Allele mining in the pepper gene pool provided new complementation effects between pvr2-eIF4E and pvr6-eIF(iso)4E alleles for resistance to pepper veinal mottle virus.

Molecular cloning of recessive resistance genes to potyviruses in a large range of host species identified the eukaryotic translation initiation factor 4E (eIF4E) as an essential determinant in the outcome of potyvirus infection. Resistance results from a few amino acid changes in the eIF4E protein encoded by the recessive resistance allele that disrupt the direct interaction with the potyviral protein VPg. In plants, several loci encode two protein subfamilies, eIF4E and eIF(iso)4E.

Functional markers for selection of potyvirus resistance alleles at the pvr2-eIF4E locus in pepper using tetra-primer ARMS-PCR.

Functional markers targeted on single nucleotide polymorphisms (SNPs) responsible for phenotypic variation constitute optimal tools for marker-assisted selection (MAS) of resistance alleles with different specificities. Here, we used the tetra-primer ARMS-PCR procedure to assay SNP signatures of four distinct alleles at the pvr2-eIF4E locus, which controls pepper resistance to several potyviruses. These simple, economical, and codominant markers open the way for MAS of pepper genotypes resistant to the potyviral strains and species that are prevalent in distinct cultivation areas across the world.

QTL analysis of fruit quality in fresh market tomato: a few chromosome regions control the variation of sensory and instrumental traits.

The organoleptic quality of tomato fruit involves a set of attributes (flavour, aroma, texture) that can be evaluated either by sensory analyses or by instrumental measures. In order to study the genetic control of this characteristic, a recombinant inbred line (RIL) population was developed from an intraspecific cross between a cherry tomato line with a good overall aroma intensity and an inbred line with medium flavour but bigger fruits. A total of 38 traits involved in organoleptic quality were evaluated.

Growth patterns of the lateral roots of young oak (Quercus robur) tree seedlings Relationship with apical diameter.

The growth patterns of the first-order lateral roots of young oak (Quercus robur L.) tree seedlings were studied and related to variation in apical diameter. Seven seedlings were grown in root observation boxes and monitored daily for 6 wk.