Evidence of cryptic introgression in tomato (Solanum lycopersicum L.) based on wild tomato species alleles

Abstract Background Many highly beneficial traits (e.g. disease or abiotic stress resistance) have been transferred into crops through crosses with their wild relatives. The 13 recognized species of tomato (Solanum section Lycopersicon) are closely related to each other and wild species genes have been extensively used for improvement of the crop, Solanum lycopersicum L. In addition, the lack of geographical barriers has permitted natural hybridization between S. lycopersicum and its closest wild relative Solanum pimpinellifolium in Ecuador, Peru and northern Chile. In order to better understand patterns of S. lycopersicum diversity, we sequenced 47 markers ranging in length from 130 to 1200 bp (total of 24 kb) in genotypes of S. lycopersicum and wild tomato species S. pimpinellifolium, Solanum arcanum, Solanum peruvianum, Solanum pennellii and Solanum habrochaites. Between six and twelve genotypes were comparatively analyzed per marker. Several of the markers had previously been hypothesized as carrying wild species alleles within S. lycopersicum, i.e., cryptic introgressions. Results Each marker was mapped with high confidence (e-30) to a single genomic location using BLASTN against tomato whole genome shotgun chromosomes (SL2.40) database. Neighbor-joining trees showed high mean bootstrap support (86.8 ± 2.34%) for distinguishing red-fruited from green-fruited taxa for 38 of the markers. Hybridization and parsimony splits networks, genomic map positions of markers relative to documented introgressions, and historical origins of accessions were used to interpret evolutionary patterns at nine markers with putatively introgressed alleles. Conclusion Of the 47 genetic markers surveyed in this study, four were involved in linkage drag on chromosome 9 during introgression breeding, while alleles at five markers apparently originated from natural hybridization with S. pimpinellifolium and were associated with primitive genotypes of S. lycopersicum. The positive identification of introgressed genes within crop species such as S. lycopersicum will help inform conservation and utilization of crop germplasm diversity, for example, facilitating the purging of undesirable linkage drag or the exploitation of novel, favorable alleles.</p

Avaliacoes da infeccao de explantes de feijoeiro por Agrobacterium tumefaciens por meio de microscopia.

Phaseolus vulgaris L. e considerada recalcitrante a transformacao por Agrobacterium tumefaciens. Contudo, alteracoes no meio de co-cultivo, utilizacao de linhagens hipervirulentas de Agrobacterium e de vetores binarios contendo genes vir demostraram que o feijoeiro e susceptivel a essa bacteria. O objetivo do presente trabalho foi estudar o efeito da sonificacao nos tecidos vegetais de feijoeiro, bem como a penetracao da Agrobacterium nas camadas subepidermicas do tecido vegetal, usando a metodologia SAAT ("Sonification-Assisted Agrobacterium-mediated Transformation"). A variedade de feijoeiro utilizada foi a Olathe Pinto, a linhagem de A. tumefaciens foi LBA4404:pTOK.Os embrioes de feijao foram pre-tratados po 14 dias em meio de multibrotacao e, entao submetidos a sonificacao (de 0 ou 60 segundos) na presenca de Agrobacterium. Apos a inoculacao foram co-cultivados por 24 horas em meio liquido seguido de 48 horas em meio solido, ambos, contendo 20 m. L -1 de acetoceringona. Os explantes inoculados foram fixadas em solucao de Karnovsk para avaliacoes em microscopia optica e eletronica de varredura. As analises da microspia demostraram a presenca de rupturas na epiderme, quebras da parede celular e invasao da Agrobacterium nos tecidos subepidermicos. Os reultados demostraram que o metodo SAAT e uma tecnica viavel para a inoculcao de Agrobacterium em explantes de P. vulgaris.bitstream/CPAC-2010/23710/1/bolpd-04.pd

Evaluation of tomato accessions for flavour and flavour-contributing components

Flavour is one of the most highly demanded consumer traits of tomato at present; poor flavour is one of the most commonly heard complaints associated with modern varieties of tomato. In order to combine flavour with other desirable fruit traits in improved cultivars, it is important to determine how much variability exists in the crucial compounds that contribute most to flavour. The objective of the present study was to determine the variability of flavour-contributing components including total soluble solids (TSS) and total titratable acids (TTA) among other subjective traits related to flavour in a core collection of tomato accessions. The core collection was comprised of 173 tomato accessions with a wide genetic background from the United States Department of Agriculture (USDA), Agricultural Research Services (ARS) Plant Genetic Resources Unit repository. The TTA varied from 0.20 to 0.64%, whereas the TSS ranged from 3.4 to 9.0%, indicating the availability of broad variation for these traits. Rinon (PI 118783), Turrialba, Purple Calabash and LA2102 were among the high TTA (>0.45%) containing accessions, whereas those with high TSS (>7.0%) were AVRDC#6, Sponzillo and LA2102. A positive correlation of overall flavour with TTA (r=0.33; P<0.05) and TSS (r=0.37; P<0.05) indicated that these two components play an important role in determining the overall flavour in tomato. Subjectively measured other traits including fruity odour and fruity flavour had positive correlations with overall flavour. Overall flavour is discussed in the context of other traits including fruit firmness. Information obtained from this study may be useful for tomato breeders aiming to improve tomato flavou

Shearlet-based regularized reconstruction in region-of-interest computed tomography

Region of interest (ROI) tomography has gained increasing attention in recent years due to its potential to reducing radiation exposure and shortening the scanning time. However, tomographic reconstruction from ROI-focused illumination involves truncated projection data and typically results in higher numerical instability even when the reconstruction problem has unique solution. To address this problem, both ad hoc analytic formulas and iterative numerical schemes have been proposed in the literature. In this paper, we introduce a novel approach for ROI tomographic reconstruction, formulated as a convex optimization problem with a regularized term based on shearlets. Our numerical implementation consists of an iterative scheme based on the scaled gradient projection method and it is tested in the context of fan-beam CT. Our results show that our approach is essentially insensitive to the location of the ROI and remains very stable also when the ROI size is rather small.Peer reviewe

Acceleration with Self-Injection for an All-Optical Radiation Source at LNF

We discuss a new compact gamma-ray source aiming at high spectral density, up to two orders of magnitude higher than currently available bremsstrahlung sources, and conceptually similar to Compton Sources based on conventional linear accelerators. This new source exploits electron bunches from laser-driven electron acceleration in the so-called self-injection scheme and uses a counter-propagating laser pulse to obtain X and gamma-ray emission via Thomson/Compton scattering. The proposed experimental configuration inherently provides a unique test-bed for studies of fundamental open issues of electrodynamics. In view of this, a preliminary discussion of recent results on self-injection with the FLAME laser is also given.Comment: 8 pages, 10 figures, 44 references - Channeling 2012 conferenc

Light Ion Accelerating Line (L3IA): Test Experiment at ILIL-PW

The construction of a novel Laser driven Light Ions Acceleration Line(L3IA) is progressing rapidly towards the operation, following the recent upgrade of the ILIL-PW laser facility. The Line was designed following the pilot experimental activity carried out earlier at the same facility to define design parameters and to identify main components including target control and diagnostic equipment, also in combination with the numerical simulations for the optimization of laser and target parameters. A preliminary set of data was acquired following the successful commissioning of the laser system >100 TW upgrade. Data include output from a range of different ion detectors and optical diagnostics installed for qualification of the laser-target interaction. An overview of the results is given along with a description of the relevant upgraded laser facility and features.Comment: 6 pages, 7 figures, 18 references, presented at the EAAC 201

AlleleCoder: a PERL script for coding co-dominant polymorphism data for PCA

A useful biological interpretation of diploid heterozygotes is in terms of the dose of the common allele (0, 1 or 2 copies). We have developed a PERL script that converts FASTA files into coded spreadsheets suitable for principal component analysis. In combination with R and R Commander, two- and three-dimensional plots can be generated for visualizing genetic relationships. Such plots are useful for characterizing plant genetic resources. This method nicely illustrated the spectrum of genetic diversity in tomato landraces and the varieties categorized according to human-mediated dispersa