Winter Reading

[Fusion_power]

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2705721/

B. Cinerea resistance introgression from S. Lycopersicoides

[ChrisK]

Several years old.

The Making of a Compound Inflorescence in Tomato and Related Nightshades

[ChrisK]

Genome-Wide Association Mapping in Tomato (Solanum lycopersicum) Is Possible Using Genome Admixture of Solanum lycopersicum var. cerasiforme

[Redbaron]

Here is some short easy reading for the less technical of us. Dear to my heart though. A breeding program to bring back the original Rutgers with both 1950's seed and recreating the original cross that produced Rutgers in the first place.

Rutger's breeding program

Apparently beyond just bringing back the old strain, there is a future interest in then using that to reselect many commercial varieties with Rutger's in their parentage to have both disease resistance, modern firmness and storage characteristics etc... AND the flavor that made Rutger's famous to begin with. Something the agronomists apparently forgot about back when originally developing the modern commercial strains. How you can breed a food crop and forget about flavor, I really have no idea. But nice to know a major agricultural university is seriously undertaking a project to correct this oversight.

Interesting article Scott. I don't think they said, but I am wondering if any of the 1950's vintage seed from the seed bank is still viable. I don't know if they maintained seed banks in liquid nitrogen in the 1950's. I also don't know how long tomato seed remains viable even when kept under the most optimum conditions. If it is viable, they could grow some of it and see how similar it is to the original description of Rutgers. Is the objective to produce a Rutgers similar hybrid or is it their intent to produce an open pollinated Rutgers using the original parentage?

Ted

[Redbaron]

Originally Posted by tedln

Interesting article Scott. I don't think they said, but I am wondering in any of the 1950's vintage seed from the seed bank is still viable. If it is, they could grow some of it and see how similar it is to the original description of Rutgers. Is the objective to produce a Rutgers similar hybrid or is it their intent to produce an open pollinated Rutgers using the original parentage?

Ted

They obviously didn't say directly, but they did imply. I suppose to know for sure you would have to get a more detailed explanation from the breeders.

But it appears to me, if I an understanding their thinking correctly, they want to recreate the original Rutger's OP variety as close as possible by using more than one technique. IE....both by recreating the original cross and selection process and by possibly breeding back to the oldest available Rutgers viable seeds they can obtain.

Oh and BTW it is a similar thought that I have had for a long time. So it is possible I am projecting my own thought process here, rather than correctly reading them.

But once you have as close as possible the original OP again....the ability to then recreate the "improved Rutger's" disease resistance and determinate versions without loosing the flavor can be attempted. Also it can be used to recreate any of the many hundreds of commercial varieties with Rutgers as a parent...but this time try to carry along the flavor genes too. The possibilities are many actually. Whether that is also a long term goal of theirs or not isn't specifically stated. But it is implied.

I guess I should be careful about reading between the lines too much. It is a fault I have. In my defence, no one is perfect!

[Fusion_power]

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3378239/
The tomato genome.

DarJones

[ChrisK]

Mapping of Micro-Tom BAC-End Sequences to the Reference Tomato Genome Reveals Possible Genome Rearrangements and Polymorphisms

[ChrisK]

Tomato responds to green peach aphid infestation with the activation of trehalose metabolism and starch accumulation

[ChrisK]

Whitefly resistance:

Acylsucrose-Producing Tomato Plants Forces Bemisia tabaci to Shift Its Preferred Settling and Feeding Site

[ChrisK]

The In Planta Transcriptome of Ralstonia solanacearum: Conserved Physiological and Virulence Strategies during Bacterial Wilt of Tomato

[ChrisK]

Involvement of SlSOS2 in tomato salt tolerance

Abstract:
The Ca2+-dependent SOS pathway has emerged as a key mechanism in the homeostasis of Na+ and K+ under saline conditions. We recently identified and functionally characterized by complementation studies in yeast and Arabidopsis the gene encoding the calcineurin-interacting protein kinase of the SOS pathway in tomato, SlSOS2.1 We also show evidences on the biotechnological potential of SlSOS2 conferring salt tolerance to transgenic tomato. The increased salinity tolerance of SlSOS2 overexpressing plants is associated with higher sodium content in stems and leaves. SlSOS2 overexpression upregulates the Na+/H+ exchange at the plasma membrane (SlSOS1) and K+,Na+/H+ antiport at the endosomal and vacuolar compartments (LeNHX2 and LeNHX4). Therefore, SlSOS2 seems to be involved in tomato salinity tolerance through regulation of Na+ extrusion from the root, active loading of Na+ into the xylem and Na+ and K+ compartmentalization.
Addendum to:
R Huertas, R Oli★as, Z Eljakaoui, FJ Galvez, J Li, PA de Morales, A Belver, MP Rodri★guez-Rosales. Overexpression of SlSOS2 (SlCIPK24) confers salt tolerance to transgenic tomato. Plant Cell Environ 2012; 35: 1467-82

[maf]

Shoot Branching and Leaf Dissection in Tomato Are Regulated by Homologous Gene Modules Bernhard L. Busch, Gregor Schmitz, Susanne Rossmann, Florence Piron, Jia Ding, Abdelhafid Bendahmane, and Klaus Theresa.

Interesting for anyone who is interested in the gene behind potato leaf expression, or indeed any leaf mutations, in tomato plants. A 2011 article, so info is up to date.

[ChrisK]

Interesting use of pennellii introgression lines. Paper is still in preview format.

Metabolic engineering of tomato fruit organic acid content guided by biochemical analysis of an introgression line

Abstract

Organic acid content is regarded as one of the most important quality traits of fresh tomatoes. However, the complexity of carboxylic acid metabolism and storage means that it is difficult to predict the best way to engineer altered carboxylic acid levels. Here we have used a biochemical analysis of a tomato introgression line with increased levels of fruit citrate and malate at breaker stage to identify a metabolic engineering target that was subsequently tested in transgenic plants. Increased carboxylic acid levels in introgression line 2-5 were not accompanied by changes in the pattern of carbohydrate oxidation by pericarp discs or the catalytic capacity of TCA cycle enzymes measured in isolated mitochondria. However, there was a significant decrease in the maximum catalytic activity of aconitase in total tissue extracts suggesting that a cytosolic isoform of aconitase was affected. To test the role of cytosolic aconitase in controlling fruit citrate levels, we analysed fruit of transgenic lines expressing an antisense construct against SlAco3b, one of the two tomato genes encoding aconitase. A GFP-fusion of SlAco3b was dual targeted to cytosol and mitochondria, while the other aconitase, SlAco3a was exclusively mitochondrial when transiently expressed in tobacco leaves. Both aconitase transcripts were decreased in fruit from transgenic lines and aconitase activity was reduced by about 30% in the transgenic lines. Other measured enzymes of carboxylic acid metabolism were not significantly altered. Both citrate and malate levels were increased in ripe fruit of the transgenic plants and, as a consequence, total carboxylic acid content was increased by 50% at maturity.

[ChrisK]

Might have been posted in a previous thread. Discussion of tomato fruit shape selection. Pretty pictures, too.

Distribution of SUN, OVATE, LC, and FAS in the Tomato Germplasm and the Relationship to Fruit Shape Diversity

Abstract

Phenotypic diversity within cultivated tomato (Solanum lycopersicum) is particularly evident for fruit shape and size. Four genes that control tomato fruit shape have been cloned. SUN and OVATE control elongated shape whereas FASCIATED (FAS) and LOCULE NUMBER (LC) control fruit locule number and flat shape. We investigated the distribution of the fruit shape alleles in the tomato germplasm and evaluated their contribution to morphology in a diverse collection of 368 predominantly tomato and tomato var. cerasiforme accessions. Fruits were visually classified into eight shape categories that were supported by objective measurements obtained from image analysis using the Tomato Analyzer software. The allele distribution of SUN, OVATE, LC, and FAS in all accessions was strongly associated with fruit shape classification. We also genotyped 116 representative accessions with additional 25 markers distributed evenly across the genome. Through a model-based clustering we demonstrated that shape categories, germplasm classes, and the shape genes were nonrandomly distributed among five genetic clusters (P < 0.001), implying that selection for fruit shape genes was critical to subpopulation differentiation within cultivated tomato. Our data suggested that the LC, FAS, and SUN mutations arose in the same ancestral population while the OVATE mutation arose in a separate lineage. Furthermore, LC, OVATE, and FAS mutations may have arisen prior to domestication or early during the selection of cultivated tomato whereas the SUN mutation appeared to be a postdomestication event arising in Europe.