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Vegetable cultivation in closed tunnels in the Tropics is impeded by high temperatures and poor pollination. This study compared the performance of cucurbits cultivated in open plots, in closed tunnels totally covered with small or large mesh nets (nethouse), and in open tunnels with a plastic film roof (rain shelter) in Tanzania over two seasons. Information was collected on climatic conditions, insect pest populations, vegetative development and yield. Temperatures were significantly higher under the tunnels than in the open plots during the day with few differences between the different tunnels. Insect pest populations were lower under nethouses than in open plots and under rain shelters, especially fruit flies. Higher marketable yields were obtained under nethouses with a small mesh (70.9 and 96.9 t.ha−1) and a large mesh (67.4 and 53.1 t.ha−1) than in open tunnels (12.9 and 9.1 t.ha−1) and in open plots (3.8 and 7.2 t.ha−1). Our results demonstrate that nets, especially with a small mesh size, provide versatile and efficient protection against major insect pests of cucumber, as well as a conducive environment for the development of the crop under local climatic conditions.

Lignocellulosic biomasses have some characteristics that hinder their use as fuel. Further, the biodegradation processes that can occur during storage can affect their energy properties. Torrefaction can improve their energy properties while reducing the impacts of storage. Near-infrared (NIR) spectroscopy could be a promising tool to estimate changes to biomass properties during storage. A series of waste feedstocks, including: sugarcane bagasse, coffee husk, eucalyptus, and pine were torrefied at 290 °C in a screw reactor, over 5, 7.5, 10, 15, or 20 min. Then, raw and torrefied biomasses were submitted to leaching and to white and brown-rot fungi, to simulate storage conditions. The weight loss (WL) due to fungal degradation after 2, 4, 8, and 12 weeks was measured and the high heating value (HHV) of all biodegradation steps, including raw and torrefied samples after leaching, were determined. All the samples were analysed by NIR spectroscopy and chemometric models were then developed. Firstly, partial least squares for discriminant analysis (PLS-DA) models successfully classified the four different residual biomasses into raw and torrefied forms according to fungal decomposition. Secondly, partial least squares regression (PLSR) models showed potential utility in an industrial context as a standardized continuous method to predict the HHV during biomass storage steps. While, PLSR models did not present good accuracy when estimating WL resulting from fungal degradation, they can be useful for screening during decision making. Further studies are required to improve and develop more efficient models to predict the fungal degradation level of stored biomasses. For exemple, in considering the class of torrefied biomasses, the model could show better predictive capacity due to less variability in the data. These results highlight the potential of NIR spectroscopy as a simple, fast, and efficient tool to analyze the degradation process over time. Such a rapid and non-destructive characterization tool could be very useful in industry to assess biomass property changes during storage.

International audience; Sahlbergella singularis is a major insect pest of cocoa in Cameroon. Conventional insecticides remain the most widely used option for mirid control, which unfortunately have adverse effects on the environment and human health. Improved methods of controlling this species, both environmentally friendly and inexpensive to farmers, are requirements. Varietal control based on the selection of resistant and/or tolerant genotypes can be an interesting approach. Nonetheless, the role of secondary metabolites (SMs) in cocoa defense against mirids is poorly documented; yet, these compounds are reported to be key elements in plant defense against herbivores. For this purpose, SMs of twelve cocoa genotypes were identified and quantified, as well as their impact on food preference by mirids. Food preference was assessed through microtests measuring cocoa attractiveness and antixenosis toward mirids. The results showed that cocoa genotypes were differently accepted as food by mirids, with a significant preference for hybrid IMC60 x SNK605 and a non-preference for T60/887. The ten other cocoa genotypes showed intermediate results. Five SMs classes: alkaloids, flavonoids, polyphenols, saponins, and tannins were identified. Their rates varied between cocoa genotypes: polyphenols > alkaloids > flavonoids > tannins, and saponins. Cocoa genotypes with high total phenolic contents were significantly preferred by S. singularis (r(alpha) = 0.86, R-2 = 74.0%, P < 0.001), while those with low saponins contents were lowly accepted (r(alpha) = - 0.83, R-2 = 68.9%, P < 0.015), independently of the levels of other SMs. Given SMs high potential to affect mirid feeding behavior, analyzing cocoa SMs composition may help in early selection of resistant cocoa varieties against S. singularis.

Plant pathogens can adapt to quantitative resistance, eroding its effectiveness. The aim of this work was to reveal the genomic basis of adaptation to such a resistance in populations of the fungus Pseudocercospora fijiensis, a major devastating pathogen of banana, by studying convergent adaptation on different cultivars. Samples from P. fijiensis populations showing a local adaptation pattern on new banana hybrids with quantitative resistance were compared, based on a genome scan approach, with samples from traditional and more susceptible cultivars in Cuba and the Dominican Republic. Whole-genome sequencing of pools of P. fijiensis isolates (pool-seq) sampled from three locations per country was conducted according to a paired population design. The findings of different combined analyses highly supported the existence of convergent adaptation on the study cultivars between locations within but not between countries. Five to six genomic regions involved in this adaptation were detected in each country. An annotation analysis and available biological data supported the hypothesis that some genes within the detected genomic regions may play a role in quantitative pathogenicity, including gene regulation. The results suggested that the genetic basis of fungal adaptation to quantitative plant resistance is at least oligogenic, while highlighting the existence of specific host-pathogen interactions for this kind of resistance.

Les plantes disposent d'une immunité naturelle qui leur permet de résister aux maladies et aux agressions parasitaires dans leur environnement. L'invention puis le développement de l'agriculture ont cependant créé des milieux très favorables à l'émergence de nouvelles maladies et au développement des épidémies. Cette vulnérabilité sanitaire s'est ensuite accentuée avec l'intensification agricole, à partir des années 1950, de sorte que le recours généralisé aux pesticides de synthèse est devenu un pilier essentiel de la production. Ce modèle est désormais remis en cause et le développement d'une protection agroécologique des cultures devient une nécessité. Comprendre comment fonctionne l'immunité des plantes et déchiffrer leur arsenal de défense face aux agressions parasitaires est essentiel pour produire des variétés résistantes et réduire la dépendance de l'agriculture à la protection chimique. Mais il faut compter avec la formidable capacité d'adaptation des populations pathogènes, qui conduit les chercheurs à imaginer des stratégies complexes pour maintenir efficace la résistance des variétés cultivées. Les gènes qui confèrent la résistance aux plantes commencent à être perçus comme un bien commun à préserver absolument. Cet ouvrage explicite les concepts fondamentaux et s'appuie sur des études de cas pour réaliser une synthèse très complète des travaux en biologie, en modélisation et en sciences sociales sur ce qu'est l'immunité végétale et sur la manière dont elle pourrait concourir à une agriculture respectueuse de l'environnement.

Cowpea (Vigna unguiculata(L. Walp) is an important grain legume for human and livestock nutrition, especially in sub-Saharan Africa. Aphid,Aphis craccivoraKoch (Homoptera: Aphididae), is one of the most widespread and destructive insect pests of cowpea and host-plant resistance is an effective approach to minimize the pest damage at seedling stage. This study was aimed at identifying resistant sources toA. craccivorawithin the cowpea mini core collection, a set of accessions from the largest world cowpea germplasm collection maintained at the International Institute of Tropical Agriculture (IITA). A total of 375 lines including 373 from IITA mini core collection, one resistant (TVu-801) and one susceptible (TVx-3236) checks were evaluated through artificial infestation in screening cages during the seedling stage. In cages, genotypes were planted in single rows containing four plants. They were arranged in an augmented design in which the two checks were sown in individual cages. Scoring for aphid population and damage levels were carried out on individual plants at 7, 14, and 21 days after planting. Advanced bioassays and biochemical analyses were conducted to investigate the mechanism of resistance toA. craccivora. Overall, three genotypes TVu-6464, TVu-1583, and TVu-15445 showed good levels of resistance comparable to the resistant check TVu-801. The HPLC analyses proved that both low sucrose levels in the plant, as well as high levels of kaempferol and quercetin, aglycones of phenolic compounds, were related with high resistance to aphids. The above genotypes with promising levels of resistance toA. craccivorawill be used in cowpea breeding programs to develop improved resistant lines against this pest.

The pink sugarcane mealybug, Saccharicoccus sacchari is one of the important pests of sugarcane in China. Infestation levels of S. sacchari on 8 sugarcane varieties were investigated at sugarcane regional trial stations (Nanning City (Dingdang), Baise City, Chongzuo City (two sites, Fusui county and Longzhou county), Laibin City, Liuzhou City and Hechi City) in 2018-2019 in Guangxi Province, China. Damage levels were assessed by counting the number of mealybugs per stalk and calculating the percentage of stalk damage. Findings indicated that there were significant differences in: i) population density and damage by S. sacchari on newly planted sugarcane varieties at Laibin in 2018; ii) population density on ratoon crops at Laibin and Chongzuo (Longzhou) in 2019; and iii) plant damage on ratoon crops at Laibin and Nanning (Dingdang) in 2019. However, no significant differences were found on the varieties at other sugarcane regional experiment stations in 2018 – 2019. Findings suggest that the sugarcane varieties of GT 11-2119 and GT 11-2320 were susceptible to S. sacchari while GT 11-1042 and ROC 22 were less so. Host plant resistance is an important component to consider in any breeding programme. Not only will these data on the infestation levels help the sugar industry in planting resistant varieties but also selecting appropriate cultivars in areas prone to infestation of mealybugs.

Sugarcane yellow mite, Oligonychus sacchari (Prostigmata: Tetranychidae), is one of the main detrimental pests in sugarcane growing areas in Iran. The early populations of mites colonize on the lower surfaces of sugarcane leaves. Because of high reproductive potential, multi-generation are produced per year under warm and humid temperature during sugarcane growing season. This pest imposes economic damage to sugar industries. Field trials were conducted on evaluation of varietal resistance of five sugarcane varieties against yellow mite during two successive seasons 2014–2015 and 2015–2016 in sugarcane fields at Salman Farsi Agro-industry unit in Ahwaz, Iran. After initiation of O. sacchari activity in fields, in each plot, fifteen leaves were selected at random and number of living mites was recorded. The results showed that there were significant differences among tested varieties. The variety IRC99-02 was the most susceptible in tested years by CP57-614 in the total number of living mites and dry-leaf even though CP69-1062 was the most resistant variety.

International audience; Agroforestry systems provide diverse ecosystem services that contribute to farmer livelihoods and the conservation of natural resources. Despite these known benefits, there is still limited understanding on how shade trees affect the provision of multiple ecosystem services at the same time and the potential trade-offs or synergies among them. To fill this knowledge gap, we quantified four major ecosystem services (regulation of pests and diseases; provisioning of agroforestry products; maintenance of soil fertility; and carbon sequestration) in 69 coffee agroecosystems belonging to smallholder farmers under a range of altitudes (as representative of environmental conditions) and management conditions, in the region of Turrialba, Costa Rica. We first analyzed the individual effects of altitude, types of shade and management intensity and their interactions on the provision of ecosystem services. In order to identify potential trade-offs and synergies, we then analyzed bivariate relationships between different ecosystem services, and between individual ecosystem services and plant biodiversity. We also explored which types of shade provided better levels of ecosystem services. The effectiveness of different types of shade in providing ecosystem services depended on their interactions with altitude and coffee management, with different ecosystem services responding differently to these factors. No trade-offs were found among the different ecosystem services studied or between ecosystem services and biodiversity, suggesting that it is possible to increase the provision of multiple ecosystem services at the same time. Overall, both low and highly diversified coffee agroforestry systems had better ability to provide ecosystem services than coffee monocultures in full sun. Based on our findings, we suggest that coffee agroforestry systems should be designed with diversified, productive shade canopies and managed with a medium intensity of cropping practices, with the aim of ensuring the continued provision of multiple ecosystem services.

When exposed to moisture, wood undergoes swelling and is susceptible to fungal degradation. Chemical modification via oligomeric lactic acid (OLA) treatment has been found to be a promising environmentally friendly solution to this disadvantage. In this study, wood was impregnated with OLA and then variously heat treated to polymerize the OLA in situ. The effect of curing temperature and time on OLA polymerization has been determined chemically. Dimensional stability was examined by water immersion and hygroscopicity measurements and biological decay resistance also evaluated. OLA impregnation followed by heat treatment enhanced wood properties. OLA cure at 160 _C for 48 h resulted in treated wood with greater dimensional stability and biological resistance.

The productivity of Arabica coffee trees in the Toba Highlands (North Sumatra) suffers from inadequate agricultural practices and virtually non-existent protection against the coffee berry borer (CBB), Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae). While awaiting the development of a CBB control programme, this study proposed to achieve a rapid gain in productivity through coffee tree pruning. A comparison between the average production of ripe berries on pruned and unpruned coffee trees showed that pruning resulted in significantly higher yields over a two-year period. Within this increased production, the quantity of infested berries remained similar in the two treatments, due to the inherent dispersion behaviour of CBB, which seemed to occur throughout the fruiting period. Proper coffee tree pruning did not lead to any harvest losses in the first year, but affected the dynamics of production with a significant increase in the second year. As that improvement did not cause any increase in the number of infested berries in the pruned coffee trees, infestation rates fell. However, towards the end of the second harvest in year two, infestation levels of those coffee trees tended to reach those of unpruned coffee trees. In the Toba Highlands, pruning is probably the first step needed to improve yields and help to reduce CBB infestations, by bolstering the generally recommended sanitation harvesting.

We investigated the expression in transgenic rice of a synthetic gene encoding the toxic part of the Bacillus thuringiensis Cry1Ba endotoxin, which was shown to exhibit a tenfold lower lethal concentration 50 (LC50) than Cry1Ac in a Striped Stem Borer (SSB) diet incorporation assay. The 1.950-bp synthetic cry1B gene, possessing an overall GC content of 58 %, was cloned under the control of the maize ubiquitin promoter first intron and first exon regions. The resulting vector, designated as pUbi-cry1B, was transferred to two commercial Mediterranean cultivars of rice, Ariete and Senia, using microprojectile acceleration-mediated transformation. Thirty-two and 47 T0 events were generated in cvs. Ariete and Senia, respectively. Southern blot and immunoblot analyses allowed the identification of 7 Senia and 1 Ariete events harbouring both an intact gene cassette and expressing Cry1B at a level ranging from 0.01 % to 0.4 % of the total soluble proteins. Three Senia and 1 Ariete events were found to be protected against second instar SSB larvae in whole plant feeding assays, exhibiting 90-100 % mortality 7 days after infestation. Spatial and temporal variation in transgene expression was further examined in resistant event 64 of cv. Ariete. Stable accumulation of Cry1B, representing 0.4 % of the total soluble proteins, was observed over the T2 to T4 generations in leaf tissue 20, 40, 70 and 90 days after germination in both young and old leaves and in internodes. Ariete event 64 was found to be fully protected from attacks of third and fourth instar SSB larvae over subsequent generations.

Résumé : L'hévéa (Hevea brasiliensis) est la seule source de caoutchouc naturel commercialisé à travers le monde. En Afrique et en Asie, la maladie 'Corynespora Leaf Fall' (CLF), causée par le champignon nécrotrophe Corynespora cassiicola, affecte les plantations hévéicoles en provoquant des défoliations massives sur les clones les plus sensibles. L’évaluation précoce de la sensibilité des clones dans les programmes de sélection est un enjeu majeur pour écarter les individus les plus sensibles des programmes de développement et ainsi réduire la pression de la maladie. Une des méthodes d’évaluation envisagée consiste à tester indirectement la sensibilité des clones aux effecteurs fongiques responsables de la virulence (test toxinique). Parmi tous les effecteurs potentiels du champignon identifiés in silico, seule la cassiicoline Cas1 a été purifiée et caractérisée à ce jour. Il s’agit d’une petite glycoprotéine sécrétée qui jouerait un rôle dans les phases précoces de l’infection en induisant la nécrose des tissus. Les souches porteuses du gène Cas1 sont parmi les plus agressives sur les clones d'hévéa testés. Néanmoins, certaines souches de C. cassiicola ne produisant pas de cassiicoline présentent tout de même une agressivité modérée, suggérant l'implication d'autres effecteurs dans l'établissement de la maladie CLF. Les objectifs de cette thèse sont (i) de déterminer si la sensibilité à la cassiicoline Cas1 est un critère de sélection pertinent pour identifier les clones d’hévéa les plus sensibles à la maladie CLF, et (ii) d’identifier chez l’hévéa des facteurs de sensibilité à la cassiicoline Cas1. Nous avons d'abord analysé l’inoculum naturel et montré que les souches porteuses du gène Cas1 représentent un quart de la population de C. cassiicola dans les plantations d’hévéa d’Afrique de l’Ouest, le reste étant majoritairement constitué de souches dépourvues du gène codant la cassiicoline (Type A/Cas0). Nous avons ensuite créé un mutant de délétion du gène Cas1 pour la souche de référence CCP et comparé sa virulence à celle de la souche sauvage. Nous avons ainsi pu montrer que la cassiicoline Cas1 est bien un effecteur de nécrotrophie déterminant pour la virulence de C. cassiicola chez l’hévéa puisque la souche délétée perd toute virulence sur les clones testés. Enfin, nous avons recherché chez l'hévéa des facteurs de sensibilité à la cassiicoline Cas1 à travers deux approches. La technique de "double hybride en levures" nous a permis d'identifier une trentaine de protéines candidates qui pourraient interagir physiquement avec la toxine. Une approche transcriptomique, nous a permis d’identifier les gènes d’hévéa dont l’expression est modifiée suite à l’application de la cassiicoline purifiée, en comparant un clone sensible (PB260) et un clone tolérant (RRIM600). En conclusion, ces travaux ont permis de mieux comprendre les mécanismes impliqués dans l'interaction compatible entre C. cassiicola et l'hévéa et ouvrent la voie de la sélection assistée par effecteur

International audience; South Africa is a large country of approximately 1.22 million km(2), made up of nine provinces with three climatic zones. Farming in the country is mostly defined by regional differences. Of the different organisms isolated from milk samples of dairy cows, Staphylococcus aureus poses a challenge to maintain udder health and wholesome dairy products for human consumption. Antibiotic resistant bacteria are therefore a potential health hazard. The objective of this study was to investigate the seasonal and regional relationships of antibiotic resistance of S. aureus, of which little is known. This study was undertaken to evaluate a data set of 3410 S. aureus isolates, taken from milk samples with a somatic cell count of > 400 000 cells/mL from commercial dairy herds. These isolates were tested for antimicrobial susceptibility using the Kirby Bauer method for ampicillin, cloxacillin, penicillin G, clindamycin, oxy-tetracycline, cephalexin, cefuroxime and tylosin. The samples were from 830 dairy herds, out of the estimated 2000 commercial dairy herds in South Africa. All the antibiotics tested, except for cephalosporins, showed a predicted prevalence of resistance of above 50% in most provinces, which is a concern. The lowest prevalence of resistance to the majority of the categories of antibiotics tested was present in KwaZulu-Natal during spring. The cephalosporins had the lowest levels of prevalence of bacterial resistance in Gauteng during winter. Resistance patterns of S. aureus to the eight antibiotics varied in the different seasons and provinces, possibly because of different weather conditions, and the action and spectrum of antibiotics.

International audience; Exotic pathogens cause severe damage in natural populations in the absence of coevolutionary dynamics with their hosts. However, some resistance to such pathogens may occur in naive populations. The objective of this study was to investigate the genetics of this so-called 'exapted' resistance to two pathogens of Asian origin (Erysiphe alphitoides and Phytophthora cinnamomi) in European oak. Host-pathogen compatibility was assessed by recording infection success and pathogen growth in a full-sib family of Quercus robur under controlled and natural conditions. Two high-resolution genetic maps anchored on the reference genome were used to study the genetic architecture of resistance and to identify positional candidate genes. Two genomic regions, each containing six strong and stable quantitative trait loci (QTLs) accounting for 12-19% of the phenotypic variation, were mainly associated with E. alphitoides infection. Candidate genes, especially genes encoding receptor-like-kinases and galactinol synthases, were identified in these regions. The three QTLs associated with P. cinnamomi infection did not colocate with QTLs found for E. alphitoides. These findings provide evidence that exapted resistance to E. alphitoides and P. cinnamomi is present in Q. robur and suggest that the underlying molecular mechanisms involve genes encoding proteins with extracellular signaling functions.

To assess damage from the pink stalk borers Sesamia spp, a field trial was carried out during 2013-2014 and 2014-2015 growing season at Salman Farsi Agro-industry Farms Iran in a randomized block design with four replications. In this experiment, the resistance of 15 sugarcane varieties including IRC99-04, IRC99-05, IRC99-06, IRC00-10, IRC00-11, IRC00-12, IRC00-13, IRC00-14, IRC00-15, IRC00-16, IRC00-17, IRC00-18, IRC00-19, IR-21 and IR-31 on stalk borers was evaluated. There were highly significant differences among varieties (P < 0.05) for internode damage and stalk damage in plant crop. Based on internode bored (%) and stalk damage (%), two varieties including IRC00-14, IRC00-13 were the most susceptible varieties and IR-31, IRC99-04, IR-21 and IRC00-16 were the most resistant varieties. Varietal resistance is an important factor for varietal development strategies and using data on varietal resistance can help sugar industry for planting appropriate cultivars in areas prone to damage from stalk borers as well as selecting appropriate cultivars in crop breeding for production of promising varieties which have good resistance level against stalk borers.

Sweet sorghum is a climate smart crop with multiple uses. The crop is susceptible to attack by the spotted stemborer, Chilo partellus (Swinhoe). This causes deadheart formation, leading to lodging of plants and consequent high economic losses. Lack of stable sources of resistance make any genetic enhancement through breeding difficult. We report a study to build up host plant resistance using transgenic technology by introducing two different classes of Bt genes (cry1Aa and cry1B) into two elite sweet sorghum genotypes of India (SSV84 and RSSV9). We devised tissue culture methods to suit the genotypes of our interest, SSV84 and RSSV9, and employed two methods of genetic transformation: the particle bombardment and in planta method of Agrobacterium. Modification of in vitro culture methods involved subculture every 3 days in the initial stages of culture and the use of precultured embryos as target tissues. For the in planta method, a floral dip for 1 h in Agrobacterium suspension supplemented with l-cysteine and Tween-20 was used. Sixteen transgenic events were generated; inheritance, integration and stable expression of the transgenes till the T4 generation were confirmed. The amount of Bt Cry1Aa protein at 25–30 days of growth ranged from 24.8 to 72.8 ng/g of fresh leaf tissue. We recorded 78.4 % larval mortality, reduced leaf damage (3.0 out of 9.0) and reduced feeding (41.0 %) over the controls in insect feed assays. Stable inheritance and expression in the in planta-derived transgenics are presented.

BGPI : équipe 2 / 5; International audience; Efficient strategies for limiting the impact of pathogens on crops require a good understanding of the factors underlying the evolution of compatibility range for the pathogens and host plants, i.e., the set of host genotypes that a particular pathogen genotype can infect and the set of pathogen genotypes that can infect a particular host genotype. Until now, little is known about the evolutionary and ecological factors driving compatibility ranges in systems implicating crop plants. We studied the evolution of host and pathogen compatibility ranges for rice blast disease, which is caused by the ascomycete Magnaporthe oryzae. We challenged 61 rice varieties from three rice subspecies with 31 strains of M. oryzae collected worldwide from all major known genetic groups. We determined the compatibility range of each plant variety and pathogen genotype and the severity of each plant pathogen interaction. Compatibility ranges differed between rice subspecies, with the most resistant subspecies selecting for pathogens with broader compatibility ranges and the least resistant subspecies selecting for pathogens with narrower compatibility ranges. These results are consistent with a nested distribution of R genes between rice subspecies.

International audience; Interspecific competition with native species during biological invasions can sometimes limit alien expansion. We aimed to determine the potential ecological effects of Limatus durhamii Theobald 1901, a native Neotropical mosquito (Diptera: Culicidae) species, on the invasive species Aedes (Stegomyia) aegypti (Linnaeus 1762) that breeds in the same artificial water containers. Development time and adult dry mass were measured in three rearing conditions: control (a single larva), intraspecific competition (two conspecific larvae), and interspecific competition (two heterospecific larvae). Food was provided ad libitum to eliminate exploitative competition. For Ae. aegypti, development time was not affected by interspecific interference competition (non-significant differences with the control) and the adult dry mass was significantly higher, meaning that individual fitness likely increased. Yet, because previous studies showed longer development time and lighter adults during competition with other invasive mosquitoes, it is likely that Ae. aegypti can express a different phenotype depending on the competing species. The similar pattern found for Li. durhamii females and the non-significant difference with the control for males explain in part why this species can compete with Ae. aegypti.

Enhancing cotton pest management using plant natural defenses has been described as a promising way to improve the management of crop pests. We here reviewed different studies on cotton growing systems to illustrate how an ancient technique called plant training, which includes plant topping and pruning, may contribute to this goal. Based on examples from cotton crops, we show how trained plants could be promoted to a state of enhanced defense that causes faster and more robust activation of their defense responses. We revisit agricultural benefits associated to this technique in cotton crops, with a focus on its potential as a supplementary tool for Integrated Pest Management (IPM). Particularly, we examine its role in mediating plant interactions with conspecific neighboring plants, pests and associated natural enemies. We propose a new IPM tool, plant training for induced defense, which involves inducing plant defense by artificial injuries. Experimental evidence from various studies shows that cotton training is a promising technique, particularly for smallholders, which can be used as part of an IPM program to significantly reduce insecticide use and to improve productivity in cotton farming.

Oaks are an important part of our natural and cultural heritage. Not only are they ubiquitous in our most common landscapes1 but they have also supplied human societies with invaluable services, including food and shelter, since prehistoric times2. With 450 species spread throughout Asia, Europe and America3, oaks constitute a critical global renewable resource. The longevity of oaks (several hundred years) probably underlies their emblematic cultural and historical importance. Such long-lived sessile organisms must persist in the face of a wide range of abiotic and biotic threats over their lifespans. We investigated the genomic features associated with such a long lifespan by sequencing, assembling and annotating the oak genome. We then used the growing number of whole-genome sequences for plants (including tree and herbaceous species) to investigate the parallel evolution of genomic characteristics potentially underpinning tree longevity. A further consequence of the long lifespan of trees is their accumulation of somatic mutations during mitotic divisions of stem cells present in the shoot apical meristems. Empirical4 and modelling5 approaches have shown that intra-organismal genetic heterogeneity can be selected for6 and provides direct fitness benefits in the arms race with short-lived pests and pathogens through a patchwork of intra-organismal phenotypes7. However, there is no clear proof that large-statured trees consist of a genetic mosaic of clonally distinct cell lineages within and between branches. Through this case study of oak, we demonstrate the accumulation and transmission of somatic mutations and the expansion of disease-resistance gene families in trees.

In this study, we investigated the resistance of C. oleifera Abel. fruit shell's probe to fungi and termites. The degree of decay of C. oleifera Abel. fruit shells inoculated with Coriolus versicolor , Pycnoporus sanguineus , Coniophora puteana and Antrodia spp . in temperate or tropical environment was assessed. The resistance of the shells to subterranean termites in a tropical chamber was also assessed. It was found that there is an overall difference between the resistance to fungi decay and to termite attack. It was found that: the degree of degradation of the shell colonized by white-rot fungi is more severe than the fragmentation of the shell by brown-rot fungi. It was also found that the white-rot decay of C. oleifera Abel. fruit shell is greater than to beech wood, and then brown-rot decay of Scots pine sapwood is severer than to C. oleifera Abel. fruit shell. The resistance of C. oleifera Abel. fruit shell to attack by the subterranean termites was found to be high. It was concluded that the fungal species was an important controlling factor to the decomposition of C. oleifera Abel. fruit shell; and that termite infestation of C. oleifera Abel. fruit shell did take place but termite mortality (100%) occurred. Based on these results, further investigations are being made in order to solve the use of massive by-product from edible tea-seed oil industries.

Key Message This article presents the enhancement in boron fixation as well as the improved biological resistance against fungi and termites for wood samples treated with tannin-caprolactam and tannin-PEG formulations. Context Although the recently developed tannin-boron wood preservatives have shown high biological protection, they presented also average resistance against weathering. The tannin-caprolactam formulations have shown improved weathering resistances and dimensional stability. Aims For this reason, more detailed biological tests were performed to evaluate the influence of the caprolactam and PEG on the biological resistance. Methods In this paper, the boron leaching of the tannin-caprolactam and tannin-PEG impregnated Scots pine specimens was observed and the biocidal effect against fungi (Antrodia spp. and Coniophora puteana) and insects (Reticulitermes flavipes and Hylotrupes bajulus) were determined according to the guidelines of EN 113, EN 117, and EN 47. Results The advanced formulations containing PEG have shown interesting resistance against fungal decay, but very low penetration and weak resistance against larvae while the tannin-caprolactam preservatives have shown overall improved biological performances and higher boron fixations. Conclusion The biocidal activity of the caprolactam-added formulations was overall enhanced and therefore these formulations are confirmed to be an interesting alternative for the wood preservation in outdoor environment.

Scots pine (Pinus sylvestris L.) sapwood specimens were subjected to a two-step treatment combining vacuum-pressure impregnation with short-chain siloxanes followed by copper deposition on the wood surface via atmospheric pressure plasma. The obtained materials were exposed to a blue stain fungus in a laboratory test following EN 152 (2011). Copper treatment alone reduced fungal colonisation, but did not fully prevent it. A two-step treatment was able to impart high resistance to Aureobasidium pullulans. Termite resistance of siloxane-treated and copper-plasma coated wood was also assessed. A laboratory no-choice test according to EN 118 (2013) revealed strong attack by Reticulitermes flavipes, but termite mortality increased compared to untreated wood. In contrast, under choice conditions, R. flavipes exhibited significant avoidance towards the treated specimens.

International audience; Thermal modification processes have been developed to increase the biological durability and dimensional stability of wood. The aim of this paper was to study the influence of ThermoWood® treatment intensity on improvement of wood decay resistance against soil-inhabiting micro-organisms, brown/white rots and termite exposures. All of the tests were carried out in the laboratory with two different complementary research materials. The main research material consisted of ash (Fraxinus excelsior L.) wood thermally modified at temperatures of 170, 200, 215 and 228 °C. The reference materials were untreated ash and beech wood for decay resistance tests, untreated ash wood for soil bed tests and untreated ash, beech and pine wood for termite resistance tests. An agar block test was used to determine the resistance to two brown-rot and two white-rot fungi according to CEN/TS 15083-1 directives. Durability against soil-inhabiting micro-organisms was determined following the CEN/TS 15083-2 directives, by measuring the weight loss, modulus of elasticity (MOE) and modulus of rupture (MOR) after incubation periods of 24, 32 and 90 weeks. Finally, Reticulitermes santonensis species was used for determining the termite attack resistance by non-choice screening tests, with a size sample adjustment according to EN 117 standard directives on control samples and on samples which have previously been exposed to soil bed test. Thermal modification increased the biological durability of all samples. However, high thermal modification temperature above 215 °C, represented by a wood mass loss (ML%) due to thermal degradation of 20%, was needed to reach resistance against decay comparable with the durability classes of ‘‘durable’’ or ‘‘very durable’’ in the soil bed test. The brown-rot and white-rot tests gave slightly better durability classes than the soil bed test. Whatever the heat treatment conditions are, thermally modified ash wood was not efficient against termite attack neither before nor after soft rot degradation.

Earthworms, as ecosystem engineers, help to mineralize soil organic matter, construct and maintain soil structure, and often stimulate plant growth and protect plants from pests. The aim of this study was (i) to determine the connection between earthworm traits and indicators of soil ecosystem services and (ii) to identify earthworm “response” traits, which are selected by the landscape or changes in the soil, and “effect” traits, which contribute to soil processes. In the southern portion of the state of Para (eastern Brazilian Amazonia), we sampled earthworms at 135 points distributed among 3 locations, 9 sub-locations and 27 farms (5 sampling points per farm). At each point, three 25 cm × 25 cm soil samples were hand-sorted for earthworms. We measured eight functional traits in 1148 individuals: relative gizzard size, type of typhlosole, length and type of caudal setae, pigmentation, overall length, thickness of septa and musculature in anterior segments. We found a significant, although relatively low, relationship between landscape classes and trait proportions. Earthworm trait proportions significantly covaried with soil parameters and indicators of soil ecosystem services. We did not find significant covariation between earthworm morphospecies and soil ecosystem services. We identified earthworm “response” traits that had been selected and assessed consequences of these changes on effects of earthworm communities (via their “effect” traits) on soil processes and ecosystem services. Typhlosole type, gizzard size and septa thickness were identified as “response” traits selected by soil and landscape conditions. These traits were also identified as “effect” traits for their influence on soil structure. Results indicated a connection between earthworm traits and landscape degradation and soil services, which is a new step toward conceptualizing earthworm ecological studies that go beyond the species level. (Resume d'auteur)

Thermal modification is an attractive alternative to improve the decay durability and dimensional stability of wood. However, thermally modified wood is generally not resistant to termite attacks, limiting the field of application of such materials. One way to overcome this drawback is to combine thermal modification treatment with an additional treatment. One such treatment is the impregnation of a boron derivative associated with appropriate vinylic monomers, which takes advantage of the thermal treatment to polymerise these monomers for boron fixation. Using this strategy, we recently showed that an impregnation of borax (2 or 4% boric acid equivalent) dissolved in a 10% aqueous solution of polyglycerolmethacrylate followed by thermal treatment under nitrogen at 220°C protects wood from both termite and decay degradations, even after leaching. Additionally, wood samples treated with a 10% polyglycerolmethacrylate aqueous solution and subjected to thermal treatment at 220°C presented improved resistance to termites while avoiding boron utilization. Based on these results, we investigate the effect of impregnation with two types of vinylic monomers, which are already used in the presence of boron, followed by thermal treatments at different temperatures. We evaluate termite and decay durability of wood to evaluate if thermal modification associated with light chemical modification could be a solution for utilization of thermally modified materials in termite-infested areas.

Thermal modification is now considered as a new ecofriendly industrial wood modification process improving mainly the material decay resistance and its dimensional stability. Most industrial thermal treatment processes use convection heat transfer which induces sometimes heterogeneous treatment temperature propagation within the oven and lead to the heterogeneity in treatment efficiency. Thus, it is common that treatment is not completely effective on several stack boards, in a same batch. The aim of this paper was to study the decay resistance variability of various European wood species thermally modified. Thermal modifications were performed around 240°C during 4h, on about 10 m3 of 27 x 152 x 2000 mm3 wood planks placed in an industrial oven having a volume of 20 m3, on the following wood species: spruce, ash, beech and poplar. All of the tests concerning the decay resistance were carried out in the laboratory using untreated beech and pine woods as reference materials. An agar block test was used to determine the resistance of thermally modified woods, leached beforehand according to EN 84 standard or not, to brown-rot and white-rot fungi, according to XP CEN/TS 15083-1. A large selection of treated wood samples was tested in order to estimate the variability of treatment efficiency. Thermal treatment increased the biological durability of all leached and un-leached modified wood samples, compared with native wood species. The treatment temperature of 240°C used in this study is sufficient to reach durability classes ''durable'' or ''very durable'' for the four wood species. However, the dispersion of weight loss values, due to the fungal attacks was very important and showed a large variability of the durability of wood which has been treated in a single batch. These results showed that there is a substantial need to develop process control and² indicator in order to insure that the quality of treated timber is properly evaluated with a view to putting this modified timber on the market under a chain of custody.

Laboratory choice and no-choice tests following the guidelines of EN 117 (2013) were performed to assess the resistance of wood modified with short- and long-chain amino-functional siloxane emulsions to subterranean termites (Reticulitermes flavipes). Scots pine sapwood was vacuum-pressure treated to reach 2, 5 and 8 % weight percent gain. Half of the specimens (including controls) were subjected to an accelerated aging test according to the standard EN 84 (1997) prior to termite testing. In addition to visual rating, mass losses were also determined. In case of the no-choice test, silicone-treated samples were not resistant according to EN 117 (2013), even though a clear reduction in mass loss had occurred. After exposure to a choice test, the modified wood samples showed 5–10 times less mass loss than control samples, even in the case of the leached specimens. This study reveals a good performance of wood modified with short-chained amino-functional siloxanes in resisting to R. flavipes when there is a choice of feeding.

The level of hydrogen peroxide (H 2 O 2 ) in plants signalizes the induction of several genes, including that of ascorbate peroxidase (APX-EC 1.11.1.11). APX isoenzymes play a central role in the elimination of intracellular H 2 O 2 and contribute to plant responses to diverse stresses. During the infection process in Theobroma cacao by Moniliophthora perniciosa oxidative stress is generated and the APX action recruited from the plant. The present work aimed to characterize the T. cacao APX involved in the molecular interaction of T. cacao – M. perniciosa . The peroxidase activity was analyzed in protein extracts from cocoa plants infected by M. perniciosa and showed the induction of peroxidases like APX in resistant cocoa plants. The cytosolic protein of T. cacao (GenBank: ABR68691.2 ) was phylogenetically analyzed in relation to other peroxidases from the cocoa genome and eight genes encoding APX proteins with conserved domains were also analyzed. The cDNA from cytosolic APX was cloned in pET28a and the recombinant protein expressed and purified (r Tc -cAPX). The secondary structure of the protein was analyzed by Circular Dichroism (CD) displaying high proportion of α-helices when folded. The enzymatic assay shows stable activity using ascorbate and guaiacol as an electron donor for H 2 O 2 reduction. The pH 7.5 is the optimum for enzyme activity. Chromatographic analysis suggests that r Tc -cAPX is a homodimer in solution. Results indicate that the r Tc -cAPX is correctly folded, stable and biochemically active. The purified r Tc -cAPX presented biotechnological potential and is adequate for future structural and functional studies.

We hypothesized that inducing systemic resistances can contribute to the control of the nematode Rotylenchulus reniformis in pineapple. In greenhouse experiments conducted in Martinique, the pineapple cultivars Smooth Cayenne and MD-2 were treated with methyljasmonate (JAME) and salicylic acid (SA), elicitors of induced systemic resistance (ISR) and systemic acquired resistance (SAR). The efficacy of the elicitors was tested by inoculating plantlets grown in individual pots with a monospecific population of R. reniformis reared on Vigna unguiculata . The final nematode populations, 45 days after inoculation on MD-2 treated with JAME were reduced by 67.0% ( p = 0.006). Nematode populations on MD-2 plants treated with SA were reduced by 55.8% ( p = 0.016). Nematode populations on SC were not reduced by the elicitors. In a second experiment, using split-root systems, JAME was applied to MD-2 plantlets and enzymatic activities involved in plant defense and stress responses were monitored for 14 h after treatment. Additional pots were inoculated with nematodes 24 h after JAME treatment and examined ten days later. Transient stress was observed along with an increase in enzymatic response after inoculation with nematodes. These results showed that the MD-2 was primed through an ISR by JAME. The question now arises whether ISR can be specifically induced only in certain pineapple cultivars. Results are discussed from the perspective of introducing new strategies to manage pineapple nematodes.

Transgenic sorghum plants were produced through particle bombardment and Agrobacterium methods in two elite, but recalcitrant genotypes of Sorghum bicolor L. Moench. Use of target cells from developing tissues (immature embryos and multiple shoot buds), pre-culture of target tissue, small size of target tissue (2-3 mm), and regular subculture improved the selection and regeneration efficiencies. Addition of amino acid l-cysteine during co-cultivation and blotting sheet interface was helpful for complete decontamination of Agrobacterium tumefaciens and regeneration of transgenic plants. We demonstrated production of transgenic sorghum plants expressing a Bacillus thuringiensis lepidopteran toxin, through tailored in vitro protocols. Our results showed that decontamination of agrobacteria employing subtle treatments aided recovery of transgenic plants in recalcitrant genotypes. We generated 14 independent transgenic lines carrying different classes of B. thuringiensis toxin genes, cry1Aa and cry1B. Many single copy events were generated in two elite parental lines, CS3541 and 296B. Accumulation of the B. thuringiensis protein in leaves during the susceptible period of plant growth ranged from 35 to 500 ng/g fresh leaf tissue. Comprehensive insect bioassays for tolerance to spotted stem borer (Chilo partellus) were conducted through leaf disk and whole plant assays. Transgenic progeny plants showed 20-30% of damage as compared to 70-80% in non-transformed controls.

In this work, we identified a gene from Theobroma cacao L. genome and cDNA libraries, named TcGlu2, that encodes a b-1,3-1,4-glucanase. The TcGlu2 ORF was 720 bp in length and encoded a polypeptide of 239 amino acids with a molecular mass of 25.58 kDa. TcGlu2 contains a conserved domain characteristic of b- 1,3-1,4-glucanases and presented high protein identity with b-1,3-1,4-glucanases from other plant species. Molecular modeling of TcGlu2 showed an active site of 13 amino acids typical of glucanase with b-1,3 and 1,4 action mode. The recombinant cDNA TcGlu2 obtained by heterologous expression in Escherichia coli and whose sequence was confirmed by mass spectrometry, has a molecular mass of about 22 kDa (with His-Tag) and showed antifungal activity against the fungus Moniliophthora perniciosa, causal agent of the witches' broom disease in cacao. The integrity of the hyphae membranes of M. perniciosa, incubated with protein TcGlu2, was analyzed with propidium iodide. After 1 h of incubation, a strong fluorescence emitted by the hyphae indicating the hydrolysis of the membrane by TcGlu2, was observed. To our knowledge, this is the first study of a cacao b-1,3-1,4-glucanase expression in heterologous system and the first analysis showing the antifungal activity of a b-1,3-1,4-glucanase, in particular against M. perniciosa.