Pathogenic potential of Beauveria pseudobassiana as bioinsecticide in protein baits for the control of the medfly Ceratitis capitata

The medfly, Ceratitis capitata (Wiedemann) (Diptera Tephritidae), is a major insect pest affecting fruit production worldwide whose control is mainly based on the use of protein baits laced with chemical insecticides. Entomopathogenic fungi are well- known to be effective against a wide spectrum of insect pests and are commonly utilized in integrated pest management and bio- logical control programs. Here, we assess the feasibility of using the recently described entomopathogenic species Beauveria pseudobassiana Rehner et Humber (Hypocreales Cordycipitaceae) as a biological insecticide in protein bait sprays for the control of the medfly. Firstly, we evaluated the pathogenicity of B. pseudobassiana against eggs, larvae, pupae and adults of the medfly. Secondly, we tested its efficacy as bioinsecticide in protein bait sprays. The results of the pathogenicity tests showed that B. pseu- dobassiana is able to infect, and lead to the death, all instar of the medfly. The efficacy of B. pseudobassiana was confirmed also when used as bioinsecticide in protein baits. In planta tests, the survival probability (Kaplan-Meier estimates) of flies in contact with the B. pseudobassiana-laced protein bait was significantly lower respect to control. Median survival time of flies treated with B. pseudobassiana-laced protein (6 ± 1.422 d) was at least three times shorter than in control (> 20 d). Based on our results, we confirmed the potential of B. pseudobassiana as bioinsecticide in entomopathogenic fungi-laced protein baits for the control of tephritid fruit flies

Draft Whole-Genome Sequence of Trichoderma gamsii T6085, a Promising Biocontrol Agent of Fusarium Head Blight on Wheat

Trichoderma gamsii T6085 is a promising beneficial isolate whose effects consist of growth inhibition of the main agents causing Fusarium head blight, reduction of mycotoxin accumulation, competition for wheat debris, and reduction of the disease in both the lab and the field. Here, we present the first genome assembly of a T. gamsii isolate, providing a useful platform for the scientific community

A statistical protocol to describe differences among nutrient utilization patterns of Fusarium spp. and Trichoderma gamsii

The Biolog® Phenotype MicroArrays™ (PM) system offers a simple and cheap tool to rapidly providing a high throughput of information about the phenotypes of fungal isolates in a short lapse of time. In order to improve the use of the PM system in fungal ecology studies, in the present work we propose a new statistical protocol based on two approaches, i.e. a functional PCA to describe similarity patterns of growth curves and a Bayesian GAMs to allow inferences on specific growth features, in order to analyse nutrient fungal utilization in a model system including four causal agents of FHB, the natural competitor Fusarium oxysporum and the beneficial isolate Trichoderma gamsii T6085. Analysis of data collected by the Biolog® Phenotype MicroArrays™ (PM) in our biological system showed a different nutritional competitive potential of the four pathogens, as well as an intermediate behaviour of the natural competitor and of our biocontrol agent. This protocol, applicable to different fungal phenotypical studies both at isolate and community level, allows a full exploitation of data obtained by PM system and provides important information about the nutritional pattern of a single isolate compared to those of other fungi, a key information to be exploited in biocontrol strategies

UV-B Pre-treatment Alters Phenolics Response to Monilinia fructicola Infection in a Structure-Dependent Way in Peach Skin

Phenolic compounds represent a large class of secondary metabolites, involved in multiple functions not only in plant life cycle, but also in fruit during post-harvest. phenolics play a key role in the response to biotic and abiotic stresses, thus their accumulation is regulated by the presence of environmental stimuli. The present work aimed to investigate how different pre-UV-B-exposures can modulate the phenolic response of peach fruit infected with Monilinia fructicola. Through HPLC-DAD-MSn, several procyanidins, phenolic acids, flavonols, and anthocyanins were detected. Both UV-B radiation and fungal infection were able to stimulate the accumulation of phenolics, dependent on the chemical structure. Regarding UV-B exposure, inoculated with sterile water, 3 h of UV-B radiation highest concentration of phenolics was found, especially flavonols and cyanidin-3-glucoside far from the wound. However, wounding decreased the phenolics in the region nearby. When peaches were pre-treated with 1 h of UV-B radiation, the fungus had an additive effect in phenolic accumulation far from the infection, while it had a subtractive effect with 3 h of UV-B radiation, especially for flavonols. Canonical discriminant analysis and Pearson correlation revealed that all phenolic compounds, except procyanidin dimer, were highly regulated by UV-B radiation, with particularly strong correlation for quercetin and kaempferol glycosides, while phenolics correlated with the fungus infection were quercetin-3-galactoside, quercetin-3-glucoside, kaempferol-3-galactoside and isorhamnetin-3-glucoside. Modulation of pathogen-induced phenolics also far from inoculation site might suggest a migration of signaling molecules from the infected area to healthy tissues

Corrigendum: UV-B Pre-treatment Alters Phenolics Response to Monilinia fructicola Infection in a Structure-Dependent Way in Peach Skin

[This corrects the article DOI: 10.3389/fpls.2018.01598.]

Draft Whole-Genome Sequence of the Biocontrol Agent Trichoderma harzianum T6776

Trichoderma harzianum T6776 is a promising beneficial isolate whose effects consist of growth promotion, positive response of photosynthetic activity, hormonal signaling, and carbon partitioning in tomato, coupled with biocontrol of plant pathogens. Here, we present the first genome assembly of T6776, providing a useful platform for the scientific community

DON on wheat crop residues: effects on mycobiota as a source of potential antagonists of Fusarium culmorum

Fusarium culmorum, a pathogenic fungal species associated with Fusarium Head Blight (FHB) of wheat, can produce the mycotoxin deoxynivalenol (DON) that is frequently found as contaminant in cereals. Wheat haulms, as decomposing plant material, are an important inoculum source of F. culmorum for subsequent crops. In the present work we exploited the mycobiota of haulms buried in natural soil as a source of potential antagonists of F. culmorum and evaluated the role played by DON in determining the composition of such mycobiota. DON was added to wheat haulm pieces that were incubated in three natural soils, namely sandy, clayey and mixed, all with a previous history of wheat cultivation. Composition of mycobiota associated with DON-treated cultural debris was evaluated and compared with mycobiota from control haulms, in order to evaluate the effect of soil type and of the presence of the mycotoxin. Our results showed that DON affected neither the number nor species profile of fungal isolates. Among fungi associated with cultural debris, thirty-nine Pythium spp. isolates were collected and five of them, both from treated and not treated haulms, were tested for their antagonistic ability against F. culmorum. The two strains showing the highest antagonistic activity were further tested against F. oxysporum, a species considered a major competitor of F. culmorum for wheat residues, and frequently recovered from haulms in our experiments. The two Pythium spp. isolates showed a positive antagonistic and mycoparasitic activity against F. culmorum, without affecting the growth of F. oxysporum. Mycobiota of haulms buried in soil represents an interesting source of potential antagonists and competitors for future exploitation in a multitrophic approach for biocontrol of FHB

An endopolygalacturonase gene of Diaporthe helianthi

In an attempt to define virulence determinants of Diaporthe helianthi, the causative agent of sunflower stem canker, the gene named Dhpg, coding for an endopolygalacturonase, was investigated in the highly virulent strain 8/96 isolated from a diseased plant in France. The 1130 bp coding sequence, in addition to 1473 bp from the upstream region, were cloned, sequenced and analyzed. Dhpg was most closely related to polygalacturonase genes from phytopathogenic fungi, such as Ophiostoma ulmi, O. novo-ulmi, and Gibberella zeae. A Southern blot RFLP analysis proved that Dhpg was represented in single-copy in the genome of the isolate 8/96. Analyses carried out both in vitro on liquid cultures and in vivo on host infected tissues provided evidence of the constitutive expression of the Dhpg transcript under all tested conditions. Moreover, an European collection of D. helianthi isolates was screened for the presence of Dhpg homologues by PCR, revealing the same single band in all French and Yugoslavian isolates, while one Romanian and all Italian isolates displayed a variable pattern. This genetic variability related to the different geographic origin of D. helianthi is consistent with data previously reported for different loci on the same set of isolates. This is the first report of a polygalacturonase gene in D. helianthi