Why old duplicated genes are not thrown away in (paleo)polyploids? Example from the petC gene in Brassica napus.

Duplication of genes at different time period, through recurrent and frequent polyploidization events, have played a major role in plant evolution, adaptation and diversification. Interestingly, some of the ancestral duplicated genes (referred as paleologs), have been maintained for millions of years, and there is still a poor knowledge of the reasons of their retention, especially when testing the phenotypic effect of individual copies by using functional genetic approaches. To fill this gap, we performed functional genetic (CRISPR-Cas9), physiological, transcriptomic and evolutionary studies to finely investigate this open question, taking the example of the petC gene (involved in cytochrome b6/f and thus impacting photosynthesis) that is present in four paleologous copies in the oilseed crop Brassica napus.

Evaluation of genome and base editing tools in maize protoplasts.

Introduction: Despite its rapid worldwide adoption as an efficient mutagenesis tool, plant genome editing remains a labor-intensive process requiring often several months of culture to obtain mutant plantlets. To avoid a waste in time and money and to test, in only a few days, the efficiency of molecular constructs or novel Cas9 variants (clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9) prior to stable transformation, rapid analysis tools are helpful.

Methods: To this end, a streamlined maize protoplast system for transient expression of CRISPR/Cas9 tools coupled to NGS (next generation sequencing) analysis and a novel bioinformatics pipeline was established.

I-SceI and customized meganucleases-mediated genome editing in tomato and oilseed rape.

Meganucleases are rare cutting enzymes that can generate DNA modifications and are part of the plant genome editing toolkit although they lack versatility. Here, we evaluated the use of two meganucleases, I-SceI and a customized meganuclease, in tomato and oilseed rape. Different strategies were explored for the use of these meganucleases.

Identifying and Isolating Meiotic Mutants in a Polyploid Brassica Crop.

This chapter provides a detailed description of TILLING and CRISPR-Cas9 approaches for the purpose of studying genes/factors involved in meiotic recombination in the polyploid species B. napus. The TILLING approach involves the screening and identification of EMS-mutagenized M2 B.

Molecular evolution and transcriptional regulation of the oilseed rape proline dehydrogenase genes suggest distinct roles of proline catabolism during development.

Six BnaProDH1 and two BnaProDH2 genes were identified in Brassica napus genome. The BnaProDH1 genes are mainly expressed in pollen and roots' organs while BnaProDH2 gene expression is associated with leaf vascular tissues at senescence. Proline dehydrogenase (ProDH) catalyzes the first step in the catabolism of proline.