Inhibitory activity of carbon quantum dots against <i>Phytophthora infestans</i> and fungal plant pathogens and their effect on dsRNA-induced gene silencing

Carbon quantum dots (CQDs) have many potential applications due to their cell-penetrating ability, biocompatibility and tunable properties. Among a variety of characteristics, the inhibition of bacteria by CQDs is often reported. However, the effect on other microorganisms, such as plant pathogenic fungi and oomycetes, is poorly studied. Here we monitored the growth of the oomycete plant pathogen Phytophthora infestans in the presence of CQDs, as well as of another three fungal plant pathogens, namely Botrytis cinerea, Alternaria alternata and Fusarium oxysporum. Moreover, the ability of CQDs to improve gene silencing caused by exogenous dsRNA in P. infestans was studied, and the toxicity of CQDs to human keratinocytes was evaluated. Our results indicate significant inhibitory activity of CQDs against P. infestans at relatively low concentrations. In a species-specific manner and to a lesser extent, the growth of the three fungal plant pathogens was also affected. We also found that the treatment of P. infestans with naked dsRNA in vitro did not trigger gene silencing. However, the mixture of CQDs with dsRNA increased RNAi efficiency, by causing a significant reduction of the transcript levels of the target gene in developing sporangia. Finally, no cytotoxicity of the CQDs, in the concentrations active against the plant pathogens, was found.</p

geno_phenotypes

geno_phenotype

PCA graph of the different body size parameters.

<p>PCA graph of the different body size parameters.</p

PCA graph of the different eye parameters.

<p>PCA graph of the different eye parameters.</p

Binary matrix data

The binary matrix (1/0) was generated using the 139 Bionumerics software (Applied Maths, Belgium). The file is in the format GenAlEx 6.5 software. The pop 1 to pop 8 means populations of MG, GO, MS, BA, TO, RS, MT, PR, respectively. Number of locus: 247; Number of samples: 246; Number of populations: 8; Column 4 to 11: number of individuals in each population; Number of regions:

Unigenes of candidate odorant-binding proteins and chemosensory proteins.

<p>Unigenes of candidate odorant-binding proteins and chemosensory proteins.</p

Correlation coefficients between the investigated traits.

<p>** Correlation is significant at the 0.01 level (2-tailed) after corrections following [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0125011#pone.0125011.ref029" target="_blank">29</a>], with as new <i>P</i> = 0.008.</p><p>* Correlation is significant at the 0.05 level (2-tailed)) after corrections following [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0125011#pone.0125011.ref029" target="_blank">29</a>], with as new <i>P</i> = 0.041.</p><p>Correlation coefficients between the investigated traits.</p

Phylogenetic relationships of the CSPs.

<p>Unrooted phylogenetic tree of CSP amino acid sequences from <i>B</i>. <i>dorsalis</i>, <i>D</i>. <i>melanogaster</i>, <i>A</i>. <i>gambiae</i>, <i>Ae</i>. <i>aegypti</i>, <i>Culex quinquefasciatus</i> and <i>Glossina morsitans morsitans</i>.</p

Distribution and comparison of male and female <i>B</i>. <i>dorsalis</i> unigenes annotated at GO level 2.

<p>The Y-axis shows the number of the sequence, the X-axis the areas of annotation and in each area, the sequences are further divided into subgroups at GO level 2.</p

List of identified epistatic effects.

<p>^a Ch-Ini and Ch-Inj represent the chromosome number-interval of the points being tested in the analysis.</p><p>^b AA is the epistatic interaction between both points (i and j).</p><p>List of identified epistatic effects.</p