A Pathogen Secreted Protein as a Detection Marker for Citrus Huanglongbing.

The citrus industry is facing an unprecedented crisis due to Huanglongbing (HLB, aka citrus greening disease), a bacterial disease associated with the pathogen Candidatus Liberibacter asiaticus (CLas) that affects all commercial varieties. Transmitted by the Asian citrus psyllid (ACP), CLas colonizes citrus phloem, leading to reduced yield and fruit quality, and eventually tree decline and death. Since adequate curative measures are not available, a key step in HLB management is to restrict the spread of the disease by identifying infected trees and removing them in a timely manner. However, uneven distribution of CLas cells in infected trees and the long latency for disease symptom development makes sampling of trees for CLas detection challenging. Here, we report that a CLas secreted protein can be used as a biomarker for detecting HLB infected citrus. Proteins secreted from CLas cells can presumably move along the phloem, beyond the site of ACP inoculation and CLas colonized plant cells, thereby increasing the chance of detecting infected trees. We generated a polyclonal antibody that effectively binds to the secreted protein and developed serological assays that can successfully detect CLas infection. This work demonstrates that antibody-based diagnosis using a CLas secreted protein as the detection marker for infected trees offers a high-throughput and economic approach that complements the approved quantitative polymerase chain reaction-based methods to enhance HLB management programs

An effector from the Huanglongbing-associated pathogen targets citrus proteases

The citrus industry is facing an unprecedented challenge from Huanglongbing (HLB). All cultivars can be affected by the HLB-associated bacterium ‘Candidatus Liberibacter asiaticus’ (CLas) and there is no known resistance. Insight into HLB pathogenesis is urgently needed in order to develop effective management strategies. Here, we use Sec-delivered effector 1 (SDE1), which is conserved in all CLas isolates, as a molecular probe to understand CLas virulence. We show that SDE1 directly interacts with citrus papain-like cysteine proteases (PLCPs) and inhibits protease activity. PLCPs are defense-inducible and exhibit increased protein accumulation in CLas-infected trees, suggesting a role in citrus defense responses. We analyzed PLCP activity in field samples, revealing specific members that increase in abundance but remain unchanged in activity during infection. SDE1-expressing transgenic citrus also exhibit reduced PLCP activity. These data demonstrate that SDE1 inhibits citrus PLCPs, which are immune-related proteases that enhance defense responses in plants

Chapitre 14: Phytopathogènes et stratégies de contrôle en aquaponie

peer reviewedAmong the diversity of plant diseases occurring in aquaponics, soil-borne pathogens, such as Fusarium spp., Phytophthora spp. and Pythium spp., are the most problematic due to their preference for humid/aquatic environment conditions. Phytophthora spp. and Pythium spp. which belong to the Oomycetes pseudo-fungi require special attention because of their mobile form of dispersion, the so-called zoospores that can move freely and actively in liquid water. In coupled aquaponics, curative methods are still limited because of the possible toxicity of pesticides and chemical agents for fish and beneficial bacteria (e.g. nitrifying bacteria of the biofilter). Furthermore, the development of biocontrol agents for aquaponic use is still at its beginning. Consequently, ways to control the initial infection and the progression of a disease are mainly based on preventive actions and water physical treatments. However, suppressive action (suppression) could happen in aquaponic environment considering recent papers and the suppressive activity already highlighted in hydroponics. In addition, aquaponic water contains organic matter that could promote establishment and growth of heterotrophic bacteria in the system or even improve plant growth and viability directly. With regards to organic hydroponics (i.e. use of organic fertilisation and organic plant media), these bacteria could act as antagonist agents or as plant defence elicitors to protect plants from diseases. In the future, research on the disease suppressive ability of the aquaponic biotope must be increased, as well as isolation, characterisation and formulation of microbial plant pathogen antagonists. Finally, a good knowledge in the rapid identification of pathogens, combined with control methods and diseases monitoring, as recommended in integrated plant pest management, is the key to an efficient control of plant diseases in aquaponics.Cos

A Genome-Wide Association Study of Diabetic Kidney Disease in Subjects With Type 2 Diabetes

dentification of sequence variants robustly associated with predisposition to diabetic kidney disease (DKD) has the potential to provide insights into the pathophysiological mechanisms responsible. We conducted a genome-wide association study (GWAS) of DKD in type 2 diabetes (T2D) using eight complementary dichotomous and quantitative DKD phenotypes: the principal dichotomous analysis involved 5,717 T2D subjects, 3,345 with DKD. Promising association signals were evaluated in up to 26,827 subjects with T2D (12,710 with DKD). A combined T1D+T2D GWAS was performed using complementary data available for subjects with T1D, which, with replication samples, involved up to 40,340 subjects with diabetes (18,582 with DKD). Analysis of specific DKD phenotypes identified a novel signal near GABRR1 (rs9942471, P = 4.5 x 10(-8)) associated with microalbuminuria in European T2D case subjects. However, no replication of this signal was observed in Asian subjects with T2D or in the equivalent T1D analysis. There was only limited support, in this substantially enlarged analysis, for association at previously reported DKD signals, except for those at UMOD and PRKAG2, both associated with estimated glomerular filtration rate. We conclude that, despite challenges in addressing phenotypic heterogeneity, access to increased sample sizes will continue to provide more robust inference regarding risk variant discovery for DKD.Peer reviewe

Production of chemicals from cellulose and biomass-derived compounds: Advances in the oxidative functionalization of levulinic acid

This chapter presents new data regarding the oxidation of levulinic acid (4-oxopentanoic acid), which can be considered as one of the most significant cellulose-derived compounds. The various synthetic applications of these procedures for the preparation of fine-chemicals and commodities are also discussed, with particular attention on the reactions that use homogeneous and heterogeneous rhenium catalysts. Such systems are able to activate hydrogen peroxide under mild experimental conditions causing selective oxidation chemistries. © 2007 American Chemical Society

Impact of bokashi fermentation on life-history traits of black soldier fly Hermetia illucens (Diptera: Stratiomyidae) larvae at an industrial scale

Larvae of the black soldier fly Hermetia illucens (Diptera: Stratiomyidae) (BSFL) are increasingly used in a circular economy context for industrial production of protein, oil, and frass, while serving as a sustainable method for managing numerous types of organic waste. On both fronts, there are ongoing efforts to optimise feedstocks for increased larval performance, yields of protein and/or oil, and efficiency of volumetric reduction of waste. Fermentation of organic waste prior to providing it to BSFL can help accomplish both goals. A few studies have individually evaluated fermenting agents such as lactic acid bacteria, yeasts, and fungi, showing that they can improve BSFL digestion of biowaste. However, the potential of co-fermentation by multiple microbes to improve waste digestion by BSFL has not been well explored. Here we tested a type of anaerobic fermentation, known as bokashi, that simultaneously uses lactic acid bacteria, yeasts, and fungi, on a common nutritious industrial feedstock (brewery’s spent grains) and on a nutritionally poor agricultural waste (unharvested oranges) on resulting life-history traits of BSFL. We show that bokashi-fermented substrates increased BSFL biomass and growth rate on both feeding substrates and dramatically reduced BSFL development duration on the nutritionally challenging oranges. Besides this, BSFL reared on fermented industrial feedstock reached the peak weight a day earlier, on average, than those feeding on the same unfermented substrate. Collectively, these effects would be beneficial for industrial BSF farming. We also highlight research areas to be tackled before bokashi fermentation can become widely adopted by the BSF farming sector

Production of chemicals from cellulose and biomass-derived compounds: Advances in the oxidative functionalization of levulinic acid

This chapter presents new data regarding the oxidation of levulinic acid (4-oxopentanoic acid), which can be considered as one of the most significant cellulose-derived compounds. The various synthetic applications of these procedures for the preparation of fine-chemicals and commodities are also discussed, with particular attention on the reactions that use homogeneous and heterogeneous rhenium catalysts. Such systems are able to activate hydrogen peroxide under mild experimental conditions causing selective oxidation chemistries. © 2007 American Chemical Society