Enabling genome editing in tropical maize lines through an improved, morphogenic regulator-assisted transformation protocol.

The recalcitrance exhibited by many maize () genotypes to traditional genetic transformation protocols poses a significant challenge to the large-scale application of genome editing (GE) in this major crop species. Although a few maize genotypes are widely used for genetic transformation, they prove unsuitable for agronomic tests in field trials or commercial applications. This challenge is exacerbated by the predominance of transformable maize lines adapted to temperate geographies, despite a considerable proportion of maize production occurring in the tropics.

Influence of culture medium pH on growth, aggregation, and biofilm formation of Xylella fastidiosa.

The major feature of Xylella fastidiosa growing in its hosts, as well as in culture media, is its cellular aggregation and biofilm formation, leading to partial obstruction of the xylem causing water stress in the plant. We report that growth, aggregation, and biofilm formation of X. fastidiosa are influenced by the medium pH.

Disruption of Xylella fastidiosa CVC gumB and gumF genes affects biofilm formation without a detectable influence on exopolysaccharide production.

Xylella fastidiosa causes citrus variegated chlorosis (CVC), a destructive disease of citrus. Xylella fastidiosa forms a biofilm inside plants and insect vectors. Biofilms are complex structures involving X.

A suitable Xylella fastidiosa CVC strain for post-genome studies.

The genome sequence of the pathogen Xylella fastidiosa Citrus Variegated Chlorosis (CVC) strain 9a5c has revealed many genes related to pathogenicity mechanisms and virulence determinants. However, strain 9a5c is resistant to genetic transformation, impairing mutant production for the analysis of pathogenicity mechanisms and virulence determinants of this fastidious phytopathogen. By screening different strains, we found out that cloned strains J1a12, B111, and S11400, all isolated from citrus trees affected by CVC, are amenable to transformation, and J1a12 has been used as a model strain in a functional genomics program supported by FAPESP (São Paulo State Research Foundation).

DNA microarray-based genome comparison of a pathogenic and a nonpathogenic strain of Xylella fastidiosa delineates genes important for bacterial virulence.

Xylella fastidiosa is a phytopathogenic bacterium that causes serious diseases in a wide range of economically important crops. Despite extensive comparative analyses of genome sequences of Xylella pathogenic strains from different plant hosts, nonpathogenic strains have not been studied. In this report, we show that X.

A new regulatory DNA motif of the gamma subclass Proteobacteria: identification of the LexA protein binding site of the plant pathogen Xylella fastidiosa.

Escherichia coli LexA protein is the repressor of a gene network whose members are directly involved in the repair of damaged DNA and in the survival of bacterial cells until DNA lesions have been eliminated. The lexA gene is widely present in bacteria, although the sequences of only three LexA-binding sites are known: Gram-positive, alpha Proteobacteria and some members of gamma Proteobacteria represented by E. coli.

Gene disruption by homologous recombination in the Xylella fastidiosa citrus variegated chlorosis strain.

Mutagenesis by homologous recombination was evaluated in Xylella fastidiosa by using the bga gene, coding for beta-galactosidase, as a model. Integration of replicative plasmids by homologous recombination between the cloned truncated copy of bga and the endogenous gene was produced by one or two crossover events leading to beta-galactosidase mutants. A promoterless chloramphenicol acetyltransferase gene was used to monitor the expression of the target gene and to select a cvaB mutant.