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Suppression or eradication of insect pest populations by the release of sterile insects is often dependent on supplementary methods of pest reduction to levels where the target pest population can be overflooded with sterile insects. Population suppression activities often take place in advance of, or coincide with, the production and release of sterile insects. Supplementary methods to remove breeding opportunities, or management methods that prevent access of pests or vectors to the hosts, may reduce the population or prevent damage or disease transmission. Insecticides have been used widely in direct applications or applied as baits, in traps, or on specific sites where the pest makes contact or reproduces, although they are increasingly being replaced by biopesticides. As sterile insect release does not kill the pest, adult biting pests or fertile mated females of the pests will continue to attack hosts after the release of sterile insects. Thus supplementary pest suppression programmes and quarantine measures are essential to prevent damage or the spread of disease. Eradication or effective pest management requires that the entire population of the pest be treated, or that the programme apply immigration barriers. It also requires taking into account interactions among control methods; they can be additive, synergistic or antagonistic. When supplementary pest control activities directly benefit the human population in areas being treated, such as in mosquito or screwworm control programmes, these area-wide suppression activities are usually acceptable to the public, but when the public receives no direct benefit from supplementary control activities such as in crop pest programmes, social resistance may develop unless public information is managed properly.

Depuis la commercialisation du coton Bt, la question de la pureté des semences utilisées par les producteurs est peu abordée, encore moins en relation avec l’analyse du système semencier dans le pays concerné. Cet article étudie le cas du Burkina Faso en 2015, pays où la couverture des surfaces en coton transgénique avec deux gènes Bt est restée partielle, jusqu’à sa suspension décidée la même année. En se basant sur les seuils de présence de gènes Bt retenus dans l’étude pour déclarer la nature conventionnelle ou transgénique des parcelles échantillonnées, 29,3 % des parcelles supposées conventionnelles l’étaient effectivement, alors que 92,6 % des parcelles supposées transgéniques l’étaient effectivement. Par contre, seulement 40 % des parcelles supposées transgéniques l’étaient bien si l’on se base sur le seuil de présence de gènes Bt attendu dans des parcelles transgéniques effectivement installées avec des semences Bollgard II suffisamment pures. L’examen du système semencier permet de lui attribuer une partie des défauts de pureté observés. Par ailleurs, si l’on considère la chronologie des événements jusqu’à la livraison des semences transgéniques par Monsanto, ces semences ne pouvaient pas contenir systématiquement les deux gènes Bt. Un tel défaut initial s’est maintenu, voire accentué par la suite. Il a certainement réduit dès le départ l’efficacité du coton Bt et, pis encore, la durabilité de son utilisation en facilitant la sélection de ravageurs résistants à chacun des deux gènes utilisés, voire simultanément aux deux. Le cas étudié souligne l’importance, pour l’efficacité et la durabilité de l’utilisation des semences transgéniques, d’avoir un système semencier qui assure et préserve la pureté des semences produites. Il révèle aussi, indépendamment de l’utilisation de ces semences, le besoin d’ajuster le système internalisé de production de semences cotonnières en Afrique francophone.

Witches' broom disease which affects cacao tree (Theobroma cacao L.) is caused by the hemibiotrophic fungus Moniliophthora perniciosa. Studies of the cacao-M. perniciosa interaction showed that the pathogenicity of M. perniciosa is associated to the presence of oxalic acid (OA). In some organisms, OA can be degraded into formate and CO2 by the oxalate decarboxylase (OXDC) enzyme. Here, we used the oxdc gene from Flammulina velutipes to generate transgenic tomato plants as a potential strategy to control M. perniciosa infection. Three transgenic T1 lines expressing the oxdc gene were obtained and two of them (P4 and P16) presented a significant delay in symptom development and higher survival percentage when inoculated with M. perniciosa in comparison to the non-transformed wild-type (WT) plants. Moreover, the P16 line test showed a decreased production of H2O2 in the presence of OA in comparison to the WT, as evidenced by the 3,3′-diaminobenzidine test. These results indicate that the P16 transgenic line is able to break down OA leading to normal plant development with few symptoms even when infected by M. perniciosa. Phenotypic and histological analysis showed differences between WT and transgenic plants. The amount of fungus hyphae was lower with thinner thickness in the transgenic plants. This study evidences of the reduction of witches' broom disease progression by the presence of the oxdc gene leading to the plant survival.

Background Since the commercial release of Bt cotton in Burkina Faso in 2009, the issue of seed purity in producers’ fields has rarely been addressed in an unbiased and objective manner. The potential for contamination of conventional seed varieties with Bt traits and the consequent threat to the continuation of organic cotton production has been documented. However, studies are rare on the varietal purity of Bt cotton seeds, despite the implications for the effectiveness and sustainability of their use. This paper compensates for the lack of research on the varietal purity of cotton seeds in Burkina Faso by reporting the results of Enzyme linked immunosorbent assay tests collected in 2015 on samples of both conventional and Bt varieties from 646 fields. Results According to the conservative criteria used to declare the presence of a Bt gene in a given variety (more than 10% of seeds of conventional variety exhibit Bt traits, and at least 90% of seeds of Bt variety exhibit Bt traits), seed purity was very questionable for both types of variety. For the supposedly conventional variety, the Cry1Ac gene was observed in 63.6% of samples, the Cry2Ab gene was observed in 59.3% of samples, and both genes were detected in 52.2% of the seed samples. Only 29.3% of the seeds that were supposed to be of conventional type contained no Bt genes. Conversely, for the labeled Bt variety, the Cry1Ac gene was found in only 59.6% of samples, the Cry2Ab gene was found in 53.6% of the samples, and both genes were found in 40.4% of the samples. Finally, for the seeds that were supposed to contain both genes (Bollguard 2), both Cry1Ac and Cry2Ab genes were found in only 40.4% of the samples, only one of the genes was found in 32.4% of the samples, and 27.2% of the seeds in the samples contained neither. Two factors are responsible for the severe lack of seed purity. First, conventional varieties are being contaminated with Bt traits because of a failure to revise the seed production scheme in Burkina Faso to prevent cross-pollination. Second, the original Bt seeds provided to Burkina Faso lacked varietal purity. The organic sector plays a very minor role in the cotton sector of Burkina Faso (production of organic cotton totaled 453 t in 2018/2019, out of national cotton production of 183 000 t). Nevertheless, the lack of purity in conventional seed varieties is a threat to efforts to expand certified organic cotton production. The poor presence of Bt proteins in supposed Bt varieties undermines their effectiveness in controlling pests and increases the likelihood of the development of resistance among pest populations. Conclusion Our results show the extent of purity loss when inadequate attention is paid to the preservation of seed purity. Pure conventional seeds could vanish in Burkina Faso, while Bt seeds do not carry the combination of the expected Bt traits. Any country wishing to embark on the use of Bt cotton, or to resume its use, as in the case of Burkina Faso, must first adjust its national seed production scheme to ensure that procedures to preserve varietal purity are enforced. The preservation of varietal purity is necessary to enable the launch or the continuation of identity-cotton production. In addition, the preservation of varietal purity is necessary to ensure the sustainable effectiveness of Bt cotton. In order to ensure that procedures to preserve varietal purity are observed, seed purity must be tested regularly, and test results must be published.

In China, a substantial amount of literature addresses pest control in Bt cotton, which is genetically engineered to resist some target pests but which had no direct effects on many other pests. The impact of this technology was positive a few years after the commercial release, but this impact was subsequently found to have reversed. The reversal was made known to the international community about ten years after the commercial release of Bt cotton in China, as a consequence of a pest complex shift phenomenon. Nevertheless, all the existing literature seldom took farmers' practices in spraying chemicals into account; farmers' opinions about using Bt cotton were not reported, nor were their opinions of their performance in growing cotton. Our study compensates for this lack through a specific and holistic approach in appraising farmers' practices, performance and opinions 15 years after the commercial release of Bt cotton in northern China. It focused on the topic of pest control by combining a survey of farmers' characteristics and opinions about Bt cotton effectiveness and profitability, as well as on their cotton cropping characteristics, with participatory detailed record-keeping of insecticide spraying by farmers. It is a holistic approach as it took into account the farming context when analyzing the results. Our results indicated that farmers used chemicals somewhat intensively, carrying out 11 insecticide sprayings on average, involving an average of 2 pest target-oriented insecticide controls. The pest complex shift phenomenon was confirmed as farmers aimed 60% of target-oriented insecticide controls at sucking pests, principally aphids even more than Lygus bugs. Three quarters of farmers were not content with Bt cotton profitability while providing a shorter protection time and most of them displayed a lack of proficiency in implementing chemical pest control. The remaining quarter of contented farmers carried out more pest target-oriented insecticide controls. Four spraying strategy factors were found and were associated notably with farmers' attitudes in controlling bollworms, aphids and Lygus bugs. The observed strategies were connected with distinct farming efficiency in a country where farming has lost its attractiveness. Sustainable use of Bt cotton calls for locally adapted actions to improve farmers' proficiency in pest control.

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.

The recovery of recombinant proteins from plant tissues is an expensive and time-consuming process involving plant harvesting, tissue extraction, and subsequent protein purification. The downstream process costs can represent up to 80% of the total cost of production. Secretion-based systems of carnivorous plants might help circumvent this problem. Drosera and Nepenthes can produce and excrete out of their tissues a digestive fluid containing up to 200 mg. L-1 of natural proteins. Based on the properties of these natural bioreactors, we have evaluated the possibility to use carnivorous plants for the production of recombinant proteins. In this context, we have set up original protocols of stable and transient genetic transformation for both Drosera and Nepenthes sp. The two major drawbacks concerning the proteases naturally present in the secretions and a polysaccharidic network composing the Drosera glue were overcome by modulating the pH of the plant secretions. At alkaline pH, digestive enzymes are inactive and the interactions between the polysaccharidic network and proteins in the case of Drosera are subdued allowing the release of the recombinant proteins. For D. capensis, a concentration of 25 μg of GFP/ml of secretion (2% of the total soluble proteins from the glue) was obtained for stable transformants. For N. alata, a concentration of 0.5 ng of GFP/ml secretions (0.5% of total soluble proteins from secretions) was reached, corresponding to 12 ng in one pitcher after 14 days for transiently transformed plants. This plant-based expression system shows the potentiality of biomimetic approaches leading to an original production of recombinant proteins, although the yields obtained here were low and did not allow to qualify these plants for an industrial platform project.

Fermentation is a critical step in the processing of high quality cocoa; however, the biochemistry behind is still not well understood at a molecular level. In this research, using a non-targeted approach, the main metabolomic changes that occur throughout the fermentation process were explored. Genetically undefined cocoa varieties from Trinidad and Tobago (n = 3), Costa Rica (n = 1) and one clone IMC-67 (n = 3) were subjected to spontaneous fermentation using farm-based and pilot plant controlled conditions. Samples were collected daily, and acetone/water/acetic acid (70/29.5/0.5%) extracts were obtained and measured using a UPLC-ESI+-Q-Tof-MS system. Analysis of pre-processed data, applying a PLS-DA model, highlighted significant differences between the three fermentation periods, observed at 0–2, 3–4 and 5–6 days, respectively. Among the most discriminating metabolites, sucrose, flavanols such as (epi) catechin, procyanidin dimers and trimers, anthocyanins and oligopeptides ranging in size from 3 to 12 amino acids were tentatively identified. In general, flavanols and sugars tended to decrease throughout fermentation, whereas most oligopeptides increased to maximal levels after 3 to 4 days of fermentation and decreased thereafter. These results shed new insight into cocoa fermentation optimization strategies and may also contribute to the development of novel alternatives for cocoa processing based on biochemical and functional values. UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro Nacional de Ciencia y Tecnología de Alimentos (CITA)

International audience; Previous results showed that the three promoter haplotypes (HP15, HP16 and HP17) of the CcDREB1D gene (encoding the dehydration responsive element binding transcription factor) found in the drought-tolerant (HP15/HP16) and drought-sensitive (HP15/HP17) clones of Coffea canephora, diverged by several single nucleotide polymorphisms and insertions/deletions. In order to compare the activities and regulation of these haplotypes in response to abiotic stresses, these sequences were cloned in front of the uidA and analyzed in transgenic tobacco (Nicotiana tabacum) for their ability to regulate the expression of this reporter gene by monitoring GUS histochemical activity under drought (mimicked by dehydration), heat shock and cold treatments. Under unstressed condition, GUS staining was mainly observed in leaf and root vascular tissues of young tobacco plants transformed by the longest sequences of CcDREB1D promoter haplotypes. These GUS activities were not observed in the same tissues of older plants as well as in plants transformed by shorter proximal regions, suggesting a developmentally-regulated activity of CcDREB1D promoters in tobacco and the existence of cis-regulatory elements essential for their regulation in distal regions. Under dehydration and heat shock conditions, GUS staining detected in leaf midribs and secondary veins of pHP17L-transformed plants was correlated with up-regulated expression of uidA reporter gene while no GUS activities were observed in pHP16L-transformed plants. However, all CcDREB1D promoter haplotypes were positively regulated by cold stress in transgenic tobacco. These results showed that these coffee promoters were recognized by the tobacco transcriptional machinery but were regulated in different manners in response to abiotic stress.

The application of agricultural biotechnology attracts the interest of many stakeholders. Genetically modified (GM) crops, for example, have been rapidly increasing in production for the last 20 years. Despite their known benefits, GM crops also pose many concerns not only to human and animal health but also to the environment. Malaysia, in general, allows the use of GM technology applications but it has to come with precautionary and safety measures consistent with the international obligations and domestic legal frameworks. This paper provides an overview of GM crop technology from international and national context and explores the governance and issues surrounding this technology application in Malaysia. Basically, GM research activities in Malaysia are still at an early stage of research and development and most of the GM crops approved for release are limited for food, feed and processing purposes. Even though Malaysia has not planted any GM crops commercially, actions toward such a direction seem promising. Several issues concerning GM crops as discussed in this paper will become more complex as the number of GM crops and varieties commercialised globally increase and Malaysia starts to plant GM crops. © 2017 Society of Chemical Industry.

Shaker-like K+ outward rectifying channel (SKOR) is involved in mediating long-distance K+ transport from roots to shoots. In this study, a Shaker-like outward K+ channel gene CmSKOR (GenBank accession number MF447462) was isolated from melon (Cucumis melo L.). Phylogenetic analysis showed that CmSKOR belongs to the SKOR-subfamily in the Shaker-like K+ channel family. Electrophysiological experiments indicated that CmSKOR was a K+-permeable channel with low affinity. Expressed in Xenopus oocytes, CmSKOR displayed classical Shaker-like outwardly rectifying K+ currents. Confocal imaging of a CmSKOR – yellow fluorescent fusion protein (YFP) in transgenic Nicotiana tabacum leaves indicated that CmSKOR was located in the plasma membrane. Transcript analysis showed CmSKOR predominantly expressed in melon roots and with lower abundance in stem and leaves. In addition, both external K+ and NaCl treatment could up-regulate the expression of CmSKOR in melon and enhance the K+ content in shoot. Constitutive overexpressed CmSKOR in Arabidopsis thaliana, the transgenic plants showed changes in root length in MS plates, displayed higher maximum photochemical efficiency of PSII (Fv/Fm), higher fresh and dry weight, and accumulation of K+ in shoot, together with the changes of transcript amount of CmSKOR with NaCl treatments in mixture substrate. In conclusion, it was proposed that CmSKOR may play the role on distributing K+ to the shoot in melon and its constitutive expression in Arabidopsis improved saline tolerance by maintaining K+ homeostasis in the plant.

International audience; The selection of the best-fit-for-purpose analytical method to be implemented in the laboratory is difficult due to availability of multiple methods, targets, aims of detection, and different kinds and sources of more or less reliable information. Several factors, such as method performance, practicability, cost of setup, and running costs need to be considered together with personnel training when selecting the most appropriate method. The aim of our work was to prepare a flexible multicriteria decision analysis model suitable for evaluation and comparison of analytical methods used for the purpose of detecting and/or quantifying genetically modified organisms, and to use this model to evaluate a variety of changing analytical methods. Our study included selection of PCR-, isothermal-, protein-, microarray-, and next-generation sequencing-based methods in simplex and/or multiplex formats. We show that the overall result of their fitness for purpose is relatively similar; however, individual criteria or a group of related criteria exposed more substantial differences between the methods. The proposed model of this decision support system enables easy modifications and is thus suitable for any other application of complex analytical methods.

Agricultural sustainability is supported by the three interlocking pillars of profit, planet, and people. Mitigation and adaptation to climate change effects is essentially environmental sustainability. The oil palm is a net sequester of carbon except when replanting forest and peat land and during forest fires. The goal of any transgenic crop modification is to use recombinant DNA methods to alter gene expression in order to create new varieties for breeders that may be difficult or impossible to produce using conventional approaches. Crop models allow one to test the effects of a range of desired prospective traits proposed to be incorporated into the new oil palm lines. This chapter provides an overview of common crop phenotyping techniques that may be useful for nonexpert. Microbial services may include production of plant growth regulators or phytohormones, provision of nutrients, enhanced tolerance to abiotic stresses, alteration of plant functional traits and induction of plant innate immune responses, and perhaps other mechanisms as well.

UMR BFP - Equipe Virologie; National audience

International audience; As a key virulence strategy to cause bacterial leaf blight, Xanthomonas oryzae pv. oryzae (Xoo) injects into the plant cell DNA-binding proteins called transcription activator-like effectors (TALEs) that bind to effector-binding elements (EBEs) in a sequence-specific manner, resulting in host gene induction. TALEs AvrXa7, PthXo3, TalC and Tal5, found in geographically distant Xoo strains, all target OsSWEET14, thus considered as a pivotal TALE target acting as major susceptibility factor during rice-Xoo interactions. Here, we report the generation of an allele library of the OsSWEET14 promoter through stable expression of TALE-nuclease (TALEN) constructs in rice. The susceptibility level of lines carrying mutations in AvrXa7, Tal5 or TalC EBEs was assessed. Plants edited in AvrXa7 or Tal5 EBEs were resistant to bacterial strains relying on the corresponding TALE. Surprisingly, although indels within TalC EBE prevented OsSWEET14 induction in response to BAI3 wild-type bacteria relying on TalC, loss of TalC responsiveness failed to confer resistance to this strain. The TalC EBE mutant line was, however, resistant to a strain expressing an artificial SWEET14-inducing TALE whose EBE was also edited in this line. This work offers the first set of alleles edited in TalC EBE and uncovers a distinct, broader range of activities for TalC compared to AvrXa7 or Tal5. We propose the existence of additional targets for TalC beyond SWEET14, suggesting that TALE-mediated plant susceptibility may result from induction of several, genetically redundant, host susceptibility genes by a single effector.

Cacao swollen shoot virus (CSSV) is a major pathogen of cacao (Theobroma cacao) in Africa, and long-standing efforts to limit its spread by the culling of infected trees have had very limited success. CSSV is a particularly difficult virus to study, as it has a very narrow host range, limited to several tropical tree species. Furthermore, the virus is not mechanically transmissible, and its insect vector can only be used with difficulty. Thus, the only efficient means to infect cacao plants that have been experimentally described so far are by particle bombardment or the agroinoculation of cacao plants with an infectious clone. We have genetically transformed three non-host species with an infectious form of the CSSV genome: two experimental hosts widely used in plant virology (Nicotiana tabacum and N. benthamiana) and the model species Arabidopsis thaliana. In transformed plants of all three species, the CSSV genome was able to replicate, and, in tobacco, CSSV particles could be observed by immunosorbent electron microscopy, demonstrating that the complete virus cycle could be completed in a non-host plant. These results will greatly facilitate the preliminary testing of CSSV control strategies using plants that are easy to raise and to transform genetically.

The roles of potassium channels from the Shaker family in stomatal movements have been investigated by reverse genetics analyses in Arabidopsis (Arabidopsis thaliana), but corresponding information is lacking outside this model species. Rice (Oryza sativa) and other cereals possess stomata that are more complex than those of Arabidopsis. We examined the role of the outward Shaker K+ channel gene OsK5.2. Expression of the OsK5.2 gene (GUS reporter strategy) was observed in the whole stomatal complex (guard cells and subsidiary cells), root vasculature, and root cortex. In stomata, loss of OsK5.2 functional expression resulted in lack of time-dependent outward potassium currents in guard cells, higher rates of water loss through transpiration, and severe slowdown of stomatal closure. In line with the expression of OsK5.2 in the plant vasculature, mutant plants displayed a reduced K+ translocation from the root system toward the leaves via the xylem. The comparison between rice and Arabidopsis show that despite the strong conservation of Shaker family in plants, substantial differences can exist between the physiological roles of seemingly orthologous genes, as xylem loading depends on SKOR and stomatal closure on GORK in Arabidopsis, whereas both functions are executed by the single OsK5.2 Shaker in rice. Since a waxy cuticle covers outer leaf tissues, water vapor diffusion into the atmosphere occurs mainly through the stomatal pores at the leaf surface. The size of the stomatal aperture is tightly regulated to optimize gas exchanges between the leaf inner tissues and the atmosphere, including CO2 intake for photosynthesis and water loss by transpiration (Lawson and Blatt, 2014). This is achieved by fine tuning of the turgor pressure of the two guard cells that surround the stomatal pore and involves a complex coordinated activity of transport systems at the guard cell plasma membrane and vacuolar membrane (Hedrich, 2012; Chen et al., 2012; Hills et al., 2012; Kollist et al., 2014). This control also affects long-distance transport of mineral nutrients from the roots, which take up these nutrients, to the aerial parts, to support plant growth (Marschner et al., 1996). Potassium ion (K+), as a major inorganic constituent of the plant cells and the most abundant cation in the cytosol, is an essential macronutrient for growth and development. It is involved in various functions, including electrical neutralization of negative charges, control of cell membrane polarization, and osmoregulation (Clarkson and Hanson, 1980; Leigh and Wyn Jones, 1984). K+ is thus the main cation absorbed by the roots and circulating within the plant at the cellular or long-distance levels. In guard cells, it is well known as a major contributor, with Cl-, NO3− and malate, to the osmolarity (Raschke and Schnabl, 1978; Willmer and Fricker, 1996). Stomatal opening is initiated by activation of plasma membrane proton pumps in guard cells, which promotes K+ influx through voltage-gated inward K+ channels, as well as anion uptake through H+-anion symporters (Blatt, 1987a; Schroeder et al., 1987; Roelfsema and Prins, 1997; Talbott and Zeiger, 1998; Guo et al., 2003; Jezek and Blatt, 2017). Conversely, stomatal closure requires inhibition of proton pumping at the guard cell membrane and activation of both anion channels and voltage-gated outward K+ channels. The molecular mechanisms responsible for inward and outward K+ fluxes across the plasma membrane have been extensively investigated in Arabidopsis (Arabidopsis thaliana). Shaker channel subunits, present as a nine-member family in Arabidopsis, have been shown to form the major pathways for these fluxes throughout the plant (Véry and Sentenac, 2003). In the Arabidopsis model species, four genes encoding Shaker channel subunits have been identified as playing a major role in root to shoot K+ translocation and in stomatal movements. The SKOR subunit, which is expressed in root pericycle and xylem parenchyma, forms outwardly rectifying channels involved in K+ secretion into the xylem sap (Gaymard et al., 1998). In stomata, the inward Shaker channel subunits KAT1 and KAT2 are involved in guard cell K+ uptake, and the outward Shaker channel GORK mediates guard cell K+ release (Ache et al., 2000; Pilot et al., 2001; Szyroki et al., 2001; Hosy et al., 2003; Lebaudy et al., 2008). Whereas these Shaker subunits have been deeply characterized in Arabidopsis, and the Shaker family, as a whole, can be considered as the best characterized family of plant membrane transport systems, little information at the molecular genetic level is yet available on this family outside Arabidopsis. The stomatal complex in rice (Oryza sativa), the current model cereal, is very different from that of Arabidopsis (Itoh et al., 2005; Franks and Farquhar, 2007; Roelfsema and Hedrich, 2009). In rice, like in other cereals, it comprises two subsidiary cells in addition to the two guard cells. Substantial differences may thus exist between rice and Arabidopsis in stomatal functioning (Mumm et al., 2011). Rice possesses two putative outward Shaker channel subunits (Pilot et al., 2003; Véry et al., 2014), named OsK5.1 (or OsSKOR) and OsK5.2 (or OsGORK; Pilot et al., 2003; Kim et al., 2015). OsK5.1 was reported to be mainly expressed in root vasculature, just as SKOR in Arabidopsis (Kim et al., 2015). In contrast, OsK5.2 was found to be expressed both in roots and shoots (Kim et al., 2015). The expression pattern of this gene at the tissue level has, however, not been described. Here, we investigate the expression pattern and role of this rice outward Shaker gene. OsK5.2 is shown to play two important roles in rice plants: it mediates K+ translocation into the xylem sap toward the shoots, and it is involved in K+ release from guard cells and stomatal movements.

This paper analyses the extent to which farmers in northern China actually benefit from market development for biotech cultivars and seeds, and how they interact with that development. It firstly appraises similarities and discrepancies observed in this development in China when compared to India, for which the experience has been more widely reported to the international community. It then examines the data obtained in Hebei Province. The results reveal strong competition with a large number of cultivars, including a substantial share of illegal cultivars, and, paradoxically, show high seed prices. In return, this competition is heightened by growers' strategies for adapting to uncertainty when buying seeds. The future of commercial seeds and the use of biotech cultivars are at stake. Competition without some form of control and regulation could be detrimental to both growers and operators in the cultivar and seed sector and could jeopardise investment in breeding and biotechnology.

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.

Evolution of resistance in pests can reduce the effectiveness of insecticidal proteins from Bacillus thuringiensis (Bt) produced by transgenic crops. We analyzed results of 77 studies from five continents reporting field monitoring data for resistance to Bt crops, empirical evaluation of factors affecting resistance or both. Although most pest populations remained susceptible, reduced efficacy of Bt crops caused by field-evolved resistance has been reported now for some populations of 5 of 13 major pest species examined, compared with resistant populations of only one pest species in 2005. Field outcomes support theoretical predictions that factors delaying resistance include recessive inheritance of resistance, low initial frequency of resistance alleles, abundant refuges of non-Bt host plants and two-toxin Bt crops deployed separately from one-toxin Bt crops. The results imply that proactive evaluation of the inheritance and initial frequency of resistance are useful for predicting the risk of resistance and improving strategies to sustain the effectiveness of Bt crops.

In plants, MADS-box transcription factors are key regulators of floral and fruit development, organ dehiscence and stress responses. Nevertheless, the functions of most of them are still unknown. In Arabidopsis thaliana, the AGL17-like clade of MAIDS-box transcription factors comprises four members. AGL17 is involved in floral induction, whereas AGL44/ANR1 is involved in the adaptive development of roots in response to nitrate. AGL21 is primarily expressed in the roots and AGL16 in the leaves, suggesting that these transcription factors may be involved in the control of vegetative development. In Oryza sativa, the AGL17-like clade comprises five members, OsMADS23, OsMADS25, O5MADS27, OsMADS57 and OsMADS61. In a first attempt to characterize their functions, we used promoter::Gus reporter gene fusions and RT-qPCR to study the expression patterns of these genes and their regulation by different external stimuli. The OsMADS23, OsMADS25, OsMADS27 and OsMADS57 promoters were active in the root's central cylinder. In addition, the OsMADS57 promoter was active in leaves, whereas the OsMADS61 promoter was only active in the leaf tips and the stem base. OsMADS25 and OsMADS27 transcripts accumulated in response to osmotic stress, whereas the expression levels of OsMADS25, OsMADS27 and OsMADS57 were slightly induced by nitrate. Each of these five genes was responsive to various hormonal treatments. These distinct expression patterns indicate that these five genes have specific and non-redundant functions that likely differs from those of their A. thaliana homologs.

The gaseous plant hormone ethylene has a wide variety of applications in agriculture and horticulture. Ethylene Response Factors (ERF) are the last transcription factors of the ethylene signalling pathway and control a large number of ethylene-responsive genes. Two Hevea brasiliensis ERF, HbERF-IXc4 and HbERF-IXc5 , are orthologs to ERF1 a key regulator at the crosstalk of ethylene and jasmonate signalling pathways. These genes were suggested to play an important role in regulating latex cell metabolism in response to tapping and ethephon stimulation. In this study, transgenic lines overexpressing HbERF-IXc4 and HbERF-IXc5 under control of 35S CaMV and HEV2.1 promoter have been conducted. Transgenic Hevea lines were obtained by Agrobacterium tumefaciens -mediated genetic transformation. The somatic embryogenesis process was affected by these modifications. Agrobacterium tumefaciens genetic transformation procedure has been developed from friable callus line for clone PB260. Hevea callus was sub-cultured as small aggregates on paromomycin selection medium. Transgenic callus lines were established from sub-aggregates showing full GFP activity. Ten transgenic lines were confirmed as transgenic by Southern blot hybridization. This result showed successfully establishment of H. brasiliensis transgenic lines. Further plant regeneration and characterization were necessary to understand the function HbERF-IXc4 and HbERF-IXc5 in latex.

Cet ouvrage traite des conditions et des modes de gestion de la culture du cotonnier, plus particulièrement en Afrique, de la semence à l'utilisation des produits, en se reposant sur les résultats de recherche. Des recommandations pratiques sont formulées à l'intention de tous les acteurs de la filière coton. Ainsi, l'intérêt d'améliorer la production du cotonnier et sa qualité est abordé sous tous les aspects de la culture par des spécialistes dans une approche systémique. Cet ouvrage propose au lecteur professionnel une aide à la décision en agronomie et en gestion des systèmes de culture, sans oublier les aspects phytosanitaires. Il informe également sur l'impact du changement climatique, sur les modalités de la transformation et de l'usage des produits et coproduits. Enfin, l'Analyse de cycle de vie appliquée à l'évaluation environnementale des systèmes cotonniers enrichit particulièrement la manière d'organiser et d'optimiser les différentes étapes de cette production d'importance mondiale. L'objectif de cet ouvrage est de proposer des pratiques agricoles et des recommandations pour l'avenir, contribuant ainsi à améliorer la culture du cotonnier et la qualité de ses produits. Rédigé dans un langage accessible, cet ouvrage est destiné à tous les professionnels de terrain.

Depuis 2008, le Burkina Faso a adopte le coton-Bt en milieu paysan, a partir de varietes africaines transformees. L’etude menee est la premiere etude ex post , couvrant la periode de 2008–2013, relative aux impacts financiers respectifs des societes cotonnieres et des paysans, chaque categorie etant prise globalement. L’etude est originale en tenant compte de la transformation genetique imparfaite des varietes utilisees. L’etude evalue les impacts financiers d’une situation reelle d’utilisation du coton-Bt par rapport a une situation de reference sans recours au coton-Bt. L’evaluation est faite aussi par rapport au scenario anticipe lors de la decision d’adoption et dont l’hypothese d’un gain de rendement au champ de 30 % n’a pas ete confirmee. L’evaluation est realisee par la methode de budget partiel avec des calculs de sensibilite a trois criteres, industriel, commercial et du prix mondial. Pour les paysans, l’impact financier est positif, mais le ratio de rentabilite du surcout des semences est a peine acceptable. Pour les societes cotonnieres, l’impact financier est modeste et est devenu negatif a mesure que le prix mondial du coton est descendu de son record historique, en raison du manque a gagner en quantite de fibre produite, de la reduction en longueur du coton fibre et de l’application d’un malus a la vente a l’exportation. L’image d’un pays fournissant habituellement un coton de qualite est negativement affectee. L’adoption du coton-Bt au Burkina Faso constitue un cas rare d’evolution technologique induisant une divergence d’impacts entre les deux categories d’acteurs avec une incidence negative potentielle sur le financement de la recherche pour poursuivre le progres technique.

The wheat gene Lr34 confers durable and partial field resistance against the obligate biotrophic, pathogenic rust fungi and powdery mildew in adult wheat plants. The resistant Lr34 allele evolved after wheat domestication through two gain-of-function mutations in an ATP-binding cassette transporter gene. An Lr34-like fungal disease resistance with a similar broad-spectrum specificity and durability has not been described in other cereals. Here, we transformed the resistant Lr34 allele into the japonica rice cultivar Nipponbare. Transgenic rice plants expressing Lr34 showed increased resistance against multiple isolates of the hemibiotrophic pathogen Magnaporthe oryzae, the causal agent of rice blast disease. Host cell invasion during the biotrophic growth phase of rice blast was delayed in Lr34-expressing rice plants, resulting in smaller necrotic lesions on leaves. Lines with Lr34 also developed a typical, senescence-based leaf tip necrosis (LTN) phenotype. Development of LTN during early seedling growth had a negative impact on formation of axillary shoots and spikelets in some transgenic lines. One transgenic line developed LTN only at adult plant stage which was correlated with lower Lr34 expression levels at seedling stage. This line showed normal tiller formation and more importantly, disease resistance in this particular line was not compromised. Interestingly, Lr34 in rice is effective against a hemibiotrophic pathogen with a lifestyle and infection strategy that is different from obligate biotrophic rusts and mildew fungi. Lr34 might therefore be used as a source in rice breeding to improve broad-spectrum disease resistance against the most devastating fungal disease of rice.

Background Aphids are serious pest on crops. By probing with their stylets, they interact with the plant, they vector viruses and when they reach the phloem they start a continuous ingestion. Many plant resistances to aphids have been identified, several have been deployed. However, some resistances breaking down have been observed. In the melon, a gene that confers resistance to aphids has been deployed in some melon-producing areas, and aphid colony development on Vat-carrying plants has been observed in certain agrosystems. The Vat gene is a NBS-LRR gene that confers resistance to the aphid species Aphis gossypii and exhibits the unusual characteristic of also conferring resistance to non-persistently transmitted viruses when they are inoculated by the aphid. Thus, we characterized patterns of resistance to aphid and virus using the aphid diversity and we investigated the mechanisms by which aphids and viruses may adapt to the Vat gene. Results Using a Vat-transgenic line built in a susceptible background, we described the Vat- spectrum of resistance to aphids, and resistance to viruses triggered by aphids using a set of six A. gossypii biotypes. Discrepancies between both resistance phenotypes revealed that aphid adaptation to Vat-mediated resistance does not occur only via avirulence factor alterations but also via adaptation to elicited defenses. In experiments conducted with three virus species serially inoculated by aphids from and to Vat plants, the viruses did not evolve to circumvent Vat-mediated resistance. We confirmed discrepancies between both resistance phenotypes by testing each aphid biotype with a set of thirteen melon accessions chosen to reflect the natural diversity of the melon. Inheritance studies revealed that patterns of resistance to virus triggered by aphids are controlled by different alleles at the Vat locus and at least another locus located at a short genetic distance. Therefore, resistance to viruses triggered by aphids is controlled by a gene cluster. Conclusions Under the Flor model, changes in the avirulence gene determine the ability of the pathogen to overcome the resistance conferred by a plant gene. The Vat gene belongs to a resistance gene family that fits this pest/pathogen–plant interaction, and we revealed an additional mechanism of aphid adaptation that potentially exists in other interactions between plants and pests or pathogens. Electronic supplementary material The online version of this article (doi:10.1186/s12870-016-0708-5) contains supplementary material, which is available to authorized users.

Hevea brasiliensis is the main commercial source of natural rubber. Reactive oxygen species (ROS) scavenging systems are involved in various biotic and abiotic stresses. Genetic engineering was undertaken to study the strengthening of plant defences by antioxidants. To that end, Hevea transgenic plant lines over-expressing a Hevea brasiliensis cytosolic HbCuZnSOD gene were successfully established and regenerated. Over-expression of the HbCuZnSOD gene was not clearly related to an increase in SOD activity in plant leaves. The impact of HbCuZnSOD gene over-expression in somatic embryogenesis and in plant development are presented and discussed. The water deficit tolerance of two HbCuZnSOD over-expressing lines was evaluated. The physiological parameters of transgenic plantlets subjected to a water deficit suggested that plants from line TS4T8An displayed lower stomatal conductance and a higher proline content. Over-expression of the HbCuZnSOD gene and activation of all ROS-scavenging enzymes also suggested that protection against ROS was more efficient in the TS4T8An transgenic line.