The DFR locus: A smart landing pad for targeted transgene insertion in tomato.

Targeted insertion of transgenes in plants is still challenging and requires further technical innovation. In the present study, we chose the tomato DFR gene involved in anthocyanin biosynthesis as a landing pad for targeted transgene insertion using CRISPR-Cas9 in a two-step strategy. First, a 1013 bp was deleted in the endogenous DFR gene.

Increase in tomato locule number is controlled by two single-nucleotide polymorphisms located near WUSCHEL.

In tomato (Solanum lycopersicum) fruit, the number of locules (cavities containing seeds that are derived from carpels) varies from two to up to 10 or more. Locule number affects fruit shape and size and is controlled by several quantitative trait loci (QTLs). The large majority of the phenotypic variation is explained by two of these QTLs, fasciated (fas) and locule number (lc), that interact epistatically with one another.

Successful gene tagging in lettuce using the Tnt1 retrotransposon from tobacco.

The tobacco (Nicotiana tabacum) element Tnt1 is one of the few identified active retrotransposons in plants. These elements possess unique properties that make them ideal genetic tools for gene tagging. Here, we demonstrate the feasibility of gene tagging using the retrotransposon Tnt1 in lettuce (Lactuca sativa), which is the largest genome tested for retrotransposon mutagenesis so far.

Systematic silencing of a tobacco nitrate reductase transgene in lettuce (Lactuca sativa L.).

A population of 50 independent transgenic lettuces transformed with a nitrate reductase coding sequence under the control of the 35S promoter was studied. None of them showed significantly lower nitrate levels when compared with the untransformed plants, despite the presence of nitrate reductase (NR) activity that derives from the transgene in at least four of the transformants. No repercussion on total NR activity (endogenous+transgenic) was detected in these plants.

A simple and efficient method for testing Lettuce mosaic virus resistance in in vitro cultivated lettuce.

The potential of a new in vitro inoculation and propagation method developed for Lettuce mosaic virus (LMV) on lettuce (Lactuca sativa L.) was evaluated by studying LMV infection on in vitro cultivated seedlings or on newly regenerated plantlets. Lettuce cultivars differing by their LMV-resistance status were inoculated with various natural LMV isolates as well as with Green Fluorescent Protein (GFP)-tagged recombinant virus isolates.