Foliar application of microdoses of sucrose to reduce codling moth Cydia pomonella L. (Lepidoptera: Tortricidae) damage to apple trees

Abstract BACKGROUND The effects of foliar applications of microdoses of sucrose to reduce the damage by the codling moth have been reported from nine trials carried in France and Algeria from 2009 to 2014. The activity of sucrose alone was assessed by comparison with an untreated control and some treatments with the Cydia pomonella granulovirus or a chemical insecticide. The addition of sucrose to these different treatments was also investigated. RESULTS The application of sucrose at 0.01% reduced the means of infested fruits with a value of Abbott's efficacy of 41.0 ± 10.0%. This involved the induction of resistance by antixenosis to insect egg laying. Indeed, it seems that acceptance of egg laying on leaves treated with sucrose was reduced. The addition of sucrose to thiacloprid improved its efficacy (59.5% ± 12.8) by 18.4%. However, the sucrose had no added value when associated with C. pomonella granulovirus treatments. CONCLUSION Foliar applications of microdoses of sucrose every 20 days in commercial orchards can partially protect against the codling moth. Its addition to thiacloprid increases the efficacy in integrated control strategies, contrary to C. pomonella granulovirus treatments. This work opens a route for the development of new biocontrol strategies

Exploring the neutral invertase–oxidative stress defence connection in Arabidopsis thaliana

Over the past decades, considerable advances have been made in understanding the crucial role and the regulation of sucrose metabolism in plants. Among the various sucrose-catabolizing enzymes, alkaline/neutral invertases (A/N-Invs) have long remained poorly studied. However, recent findings have demonstrated the presence of A/N-Invs in various organelles in addition to the cytosol, and their importance for plant development and stress tolerance. A cytosolic (At-A/N-InvG, At1g35580) and a mitochondrial (At-A/N-InvA, At1g56560) member of the A/N-Invs have been analysed in more detail in Arabidopsis and it was found that At-A/N-InvA knockout plants show an even more severe growth phenotype than At-A/N-InvG knockout plants. The absence of either A/N-Inv was associated with higher oxidative stress defence gene expression, while transient overexpression of At-A/N-InvA and At-A/N-InvG in leaf mesophyll protoplasts down-regulated the oxidative stress-responsive ascorbate peroxidase 2 (APX2) promoter. Moreover, up-regulation of the APX2 promoter by hydrogen peroxide or abscisic acid could be blocked by adding metabolizable sugars or ascorbate. A hypothetical model is proposed in which both mitochondrial and cytosolic A/N-Invs can generate glucose as a substrate for mitochondria-associated hexokinase, contributing to mitochondrial reactive oxygen species homeostasis

Plants in silico:Why, why now and what? --- An integrative platform for plant systems biology research

A paradigm shift is needed and timely in moving plant modelling from largely isolated efforts to a connected community endeavour that can take full advantage of advances in computer science and in mechanistic understanding of plant processes. Plants in silico (Psi) envisions a digital representation of layered dynamic modules, linking from gene networks and metabolic pathways through to cellular organization, tissue, organ and whole plant development, together with resource capture and use efficiency in dynamic competitive environments, ultimately allowing a mechanistically rich simulation of the plant or of a community of plants in silico. The concept is to integrate models or modules from different layers of organization spanning from genome to phenome to ecosystem in a modular framework allowing the use of modules of varying mechanistic detail representing the same biological process. Developments in high-performance computing, functional knowledge of plants, the internet and open-source version controlled software make achieving the concept realistic. Open source will enhance collaboration and move towards testing and consensus on quantitative theoretical frameworks. Importantly, Psi provides a quantitative knowledge framework where the implications of a discovery at one level, for example, single gene function or developmental response, can be examined at the whole plant or even crop and natural ecosystem levels

Genotype and Growing Environment Interaction Shows a Positive Correlation between Substrates of Raffinose Family Oligosaccharides (RFO) Biosynthesis and Their Accumulation in Chickpea (Cicer arietinum L.) Seeds

To develop genetic improvement strategies to modulate raffinose family oligosaccharides (RFO) concentration in chickpea (Cicer arietinum L.) seeds, RFO and their precursor concentrations were analyzed in 171 chickpea genotypes from diverse geographical origins. The genotypes were grown in replicated trials over two years in the field (Patancheru, India) and in the greenhouse (Saskatoon, Canada). Analysis of variance revealed a significant impact of genotype, environment, and their interaction on RFO concentration in chickpea seeds. Total RFO concentration ranged from 1.58 to 5.31 mmol/100 g and from 2.11 to 5.83 mmol/100 g in desi and kabuli genotypes, respectively. Sucrose (0.60−3.59 g/100 g) and stachyose (0.18−2.38 g/ 100 g) were distinguished as the major soluble sugar and RFO, respectively. Correlation analysis revealed a significant positive correlation between substrate and product concentration in RFO biosynthesis. In chickpea seeds, raffinose, stachyose, and verbascose showed a moderate broad sense heritability (0.25−0.56), suggesting the use of a multilocation trials based approach in chickpea seed quality improvement programs

Sugars and plant innate immunity

Sugars are involved in many metabolic and signaling pathways in plants. Sugar signals may also contribute to immune responses against pathogens and probably function as priming molecules leading to PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI) in plants. These putative roles also greatly depend on coordinated relationships with hormones and the light status in an intricate network. Although evidences in favor of sugar-mediated plant immunity are accumulating, more in-depth fundamental research is required to unravel the sugar signaling pathways involved. This might pave the way to use biodegradable sugar-(like) compounds to counteract plant diseases, as cheaper and safer alternatives for toxic agrochemicals.status: publishe

Sweet immunity in the plant circadian regulatory network

All organisms have an internal timing mechanism, termed the circadian clock, to anticipate the light/dark cycle. The clock, with an oscillating rhythm that approximates 24 h, is a rather robust system persisting to a great extent in continuous light and dark. It is widely accepted that plant growth and development are regulated by the clock, hormones and sugar signals. On the one hand, sugar signalling can affect circadian rhythms by altering the expression pattern of clock-regulated genes. More in particular, the clock seems to be particularly sensitive to sucrose mediated signalling which is also associated with immunity and abiotic stress responses. Also, hormonal interaction with the clock can contribute to appropriate plant immune responses. Recent data show a prominent role for the clock in growth and stress responses. On the other hand, the clock seems to be essential in controlling the gene expression and activity of an array of carbohydrate metabolizing enzymes, suggesting a complex reciprocal relationship between the clock and metabolic signalling processes. Therefore, the clock fulfills a crucial role at the heart of cellular networks. The players involved in the complex plant circadian network and their possible contribution to the novel “sweet immunity” concept are discussed.status: publishe

Targeted delivery of a short antimicrobial peptide (CM11) against Helicobacter pylori gastric infection using concanavalin A-coated chitosan nanoparticles

Abstract Helicobacter pylori is the cause of most cases of stomach ulcers and also causes some digestive cancers. The emergence and spread of antibiotic-resistant strains of H. pylori is one of the most important challenges in the treatment of its infections. The present study aims to develop a concanavalin A (ConA) coated chitosan (CS) nanocarrier-based drug delivery for the targeted release of peptides to the site of H. pylori infection. Accordingly, chitosan was used as an encapsulating agent for CM11 peptide delivery by applying ionotropic gelation method. Con-A was used for coating CS nanoparticles to target H. pylori. The CS NPs and ConA-CS NPs were characterized by FTIR, dynamic light scattering (DLS), and scanning electron microscopy (SEM). The MIC of CM11-loaded ConA-CS NPs against H. pylori SS1 strain was analyzed in vitro. In order to evaluate the treatment efficiency in vivo, a gastric infection model of H. pylori SS1 strain was established in mice and histopathological studies and IL-1β cytokine assay were performed. Based on the results, the size frequency for CS NPs and ConA-CS NPs was about 200 and 350 nm, respectively. The prepared CM11-loaded ConA-CS NPs exhibited antibacterial activity against H. pylori SS1 strain with a concentration of 32 µg/ml. The highest healing process was observed in synthesized CM11-loaded ConA-CS NPs treatments and a significant decrease in IL-1β was observed. Our findings highlight the potential of chitosan nanoparticles as a drug delivery vehicle in the treatment of gastric infection model of H. pylori SS1 strain. Graphical Abstrac