Plasmopara viticola (Berk. et Curt.) Berl. and de Toni, the agent of downy mildew, is one of the most important pathogens of European grapevine ( Vitis vinifera L.). Extensive evaluation of cultivated grapevine germplasm has highlighted the existence of resistant phenotypes in the Georgian (Southern Caucasus) germplasm. Resistance is shown as a reduction in disease severity. Unraveling the genetic architecture of grapevine response to P. viticola infection is crucial to develop resistant varieties and reduce the impact of disease management. The aim of this work was to apply a genome-wide association (GWA) approach to a panel of Georgian-derived accessions phenotyped for P. viticola susceptibility and genotyped with Vitis18kSNP chip array. GWA identified three highly significant novel loci on chromosomes 14 ( Rpv29 ), 3 ( Rpv30 ) and 16 ( Rpv31 ) associated with a low level of pathogen sporulation. Rpv29 , Rpv30 , and Rpv31 loci appeared to be associated with plant defense genes against biotic stresses, such as genes involved in pathogen recognition and signal transduction. This study provides the first evidence of resistant loci against P. viticola in V. vinifera germplasm, and identifies potential target genes for breeding P. viticola resistant grapevine cultivars.

No abstract

Grapevine (Vitis vinifera) is one of the most widely cultivated plant species of agricultural interest, and is extensively appreciated for its fruits and the wines made from its fruits. Considering the high socio-economic impact of the wine sector all over the world, in recent years, there has been an increase in work aiming to investigate the biodiversity of grapevine germplasm available for breeding programs. Various studies have shed light on the genetic diversity characterizing the germplasm from the cradle of V. vinifera domestication in Georgia (South Caucasus). Georgian germplasm is placed in a distinct cluster from the European one and possesses a rich diversity for many different traits, including eno-carpological and phenological traits; resistance to pathogens, such as oomycetes and phytoplasmas; resistance to abiotic stresses, such as sunburn. The aim of this review is to assess the potential of Georgian cultivars as a source of useful traits for breeding programs. The unique genetic and phenotypic aspects of Georgian germplasm were unraveled, to better understand the diversity and quality of the genetic resources available to viticulturists, as valuable resources for the coming climate change scenario.

Background A wide range of frequency of azole‐resistance in A fumigatus in different patient populations worldwide was observed threatening to reduce therapeutic options. Objectives Estimate the prevalence of azole‐resistance, investigate the molecular mechanisms of resistance, compare the genotypes of resistant clinical isolates with those from the surrounding environment. Methods Aspergillus isolates were collected by seven Italian hospital microbiology laboratories. Strains were isolated from different clinical samples from unselected patients. The azole‐resistance was evaluated using screening test and microdilution EUCAST method. The molecular mechanism of resistance was performed sequencing the cyp51A gene. Resistant isolates were genotyped by microsatellite analysis and their profiles compared with those of azole‐resistant isolates from previous Italian studies. Results 425 Aspergillus isolates from 367 patients were analysed. The azole‐resistance rates were 4.9% and 6.6% considering all Aspergillus spp. isolates and the A fumigatus sensu stricto, respectively. All resistant isolates except one were from a single hospital. Two rare azole‐resistant species were identified: A thermomutatus and A lentulus. The predominant resistance mechanism was TR34/L98H. No correlation between the clinical resistant strains and environmental isolates from patients’ home/work/ward was observed. The analysis of the molecular correlation between the resistant clinical strains collected in the present study and those of environmental and clinical origin collected in previous Italian studies reveals a progressive diversification of azole‐resistant genotypes starting from a founder azole‐resistant genotype. Conclusions This study confirms the trend of azole‐resistance rate in Italy, showing a geographical difference. Data reinforce the importance of surveillance programmes to monitor the local epidemiological situation.

Type I RIPs have not been identified in oil palm. EgRIP-1a and EgRIP-1b transcripts were partially isolated from roots and basal stems of oil palm seedlings with high similarity to type I RIPs. Expression levels were altered during plant-pathogen interaction and their proteins were 28-30 kD with an estimated pI value of 10.0. Depurination of yeast 26S rRNA by EgRIP proteins demonstrated specific ribosome-inactivating activity. EgRIP proteins showed inhibition on G. boninense mycelial growth with 44.1% at 5 DAI. It was concluded that the novel EgRIPs are type I and demonstrated to have antifungal effect against G. boninense.