Embryogenic cell suspension cultures of garlic (Allium sativum L.) as method for mass propagation and potential material for genetic improvement

4th International Symposium on Edible Alliaceae Location: Beijing, China, 2004/04/21-26International audienceEmbryogenic calluses were induced from young leaf explants of garlic (Allium sativum L). Four cultivars, ‘Rouge de la Réunion’, ‘Messidrome’, ‘Morasol’ and ‘Printanor’ have been successfully tested. These calluses expressed up to 90% of embryogenic calluses differentiating globular somatic embryos after 2 months on N6 modified medium supplemented with 2,4-D (0.1 mg l-1) and kinetin (0.5 mg l-1). Embryogenic calluses were used to establish cell suspension cultures of the above-mentioned cultivars. Friable calluses were induced from compact ones, and could give rise to the production of cell suspension cultures composed of small aggregates of embryogenic cells. These suspension cultures were maintained in liquid medium based on N6 modified macro-nutrients and supplemented with 2,4-D/benzyladenine (0.3 mg l-1/0.1 mg l-1). The packed cell volume (PCV) of the suspension cultures increased 2-fold in a 2-week period. These cell suspension cultures led to successful regeneration of mature embryos and their conversion into plantlets. Optimal embryo regeneration efficiency was obtained after plating on semi-solid medium base on N6 macro-nutrients and a balance in 2,4-D/Kinetin (0.1 mg l-1/0.5 mg l-1). A large number of somatic embryos (potentially 8 x 109 to 1011) could be produced per year for each cultivar. The conversion into plantlet was approximately 50%. Plants were successfully acclimatised in greenhouse. Histological analyses were performed along the suspension cultures and regeneration process, and helped for establishing the sequence of culture media. The somatic embryogenic nature was confirmed by single cell origin and polar development of the regenerants. This protocol was used in a goal of mass propagation of garlic plants true to the original type. It would be a key tool for biotechnologies in genetic improvement of garlic

Etude en canal expérimental de l'influence de la vitesse de l'écoulement de surface, de la submergence et de la forme du lit sur le transfert de quatre pesticides

National audienceL'étude a pour objectif de mieux comprendre l'influence de l'hydrodynamique sur le transfert de pesticides dans les fossés agricoles à écoulement permanent, situation très fréquente en saison hivernale en milieu agricole drainé. Trois paramètres ont été retenus : i) la vitesse de l'écoulement de surface ; ii) la submergence (rapport entre les hauteurs moyennes des formes du lit et de la lame d'eau) et iii) la forme du lit. Leur influence a été étudiée en conditions semi-contrôlées au sein d'un canal expérimental saturé en eau et dont le fond était tapissé d'un substrat simplifié constitué d'un assemblage de fibres de chanvre, choisi pour limiter les sources de variabilité liée à la grande hétérogénéité des substrats naturels de fossés. Le substrat retenu présente une composition majoritairement organique et l'existence de produits commerciaux standards (rouleaux de chanvre de 10 cm d'épaisseur et de plusieurs mètres de long) facilite sa mise en ½uvre tout en assurant une bonne homogénéité et stabilité dans le temps. Deux herbicides (isoproturon, diuron) et deux fongicides (azoxystrobine, tébuconazole) ont été sélectionnés dans l'étude. Des essais préliminaires au laboratoire ont montré que leurs capacités d'adsorption sur le substrat simplifié étaient intermédiaires entre celles sur substrats naturels composés de sédiments ou de feuilles mortes. La comparaison des différentes expérimentations en canal indique qu'une augmentation de la vitesse de l'écoulement de surface favorise le transfert des pesticides vers le lit, ainsi que la cinétique de ce transfert. Le constat est le même lorsqu'on augmente la submergence (donc la hauteur relative des formes du substrat), ou bien lorsqu'on passe d'une géométrie de petites formes en « dunes » à une géométrie de grandes formes en « créneau ». L'influence de chaque paramètre semble être interdépendante. Des pistes sont données pour la transposition des résultats en appui à une meilleure gestion des fossés agricoles pour favoriser la limitation du transfert des pesticides

Evidence of a somatic embryogenesis process for plant regeneration in garlic (Allium sativum L.)

A protocol has been developed for somatic embryogenesis and plant regeneration of the garlic (Allium sativum L.) variety Rouge de la Reunion. Young leaf sections or root sections from in vitro plants were used as explants source. Callus was produced on these explants. Callus production was optimal on explants derived from root sections, but callus from young leaves expressed higher embryogenic potential. Up to 75% of such embryogenic callus differentiated globular somatic embryos after 2 months on B5 medium supplemented with 2,4-D (0.1 mg l-1) and kinetin (0.5 mg l-1). Up to 30% of the somatic embryos were converted into plants with shoots and roots after 8 weeks on a BDS medium with BAP (0.3 mg l-1). Histological analysis was performed along the regeneration and confirmed the somatic embryogenic nature of the process. Plants were successfully acclimatised in a greenhouse. (Résumé d'auteur

Optical measurement of edema of limb

This thesis deals with methods of edema measuring. In my work, I designed hardware and software solutions for a device reconstructing surface of the limb part. Purpose of my work is evaluating discussing possibilities of this device. For making 3D reconstruction of scene from 2D images I made reconstruction program. For acquisition of images a device controlled by Arduino platform was constructed, the whole device is realized in program language Matlab. In the end of the thesis is described, how to improve the device for using in real conditions

Building a cluster of NLR genes conferring resistance to pests and pathogens: the story of the Vat gene cluster in cucurbits

International audienceMost molecularly characterized plant resistance genes (R genes) belong to the nucleotide-binding-site-leucine-rich-repeat (NLR) receptor family and are prone to duplication and transposition with high sequence diversity. In this family, the Vat gene in melon is one of the few R genes known for conferring resistance to insect, i.e., Aphis gossypii , but it has been misassembled and/or mispredicted in the whole genomes of Cucurbits. We examined 14 genomic regions (about 400 kb) derived from long-read assemblies spanning Vat -related genes in Cucumis melo , Cucumis sativus, Citrullus lanatus, Benincasa hispida, Cucurbita argyrosperma , and Momordica charantia . We built the phylogeny of those genes. Investigating the paleohistory of the Vat gene cluster, we revealed a step by step process beginning from a common ancestry in cucurbits older than 50 my. We highlighted Vat exclusively in the Cucumis genera, which diverged about 20 my ago. We then focused on melon, evaluating a minimum duplication rate of Vat in 80 wild and cultivated melon lines using generalist primers; our results suggested that duplication started before melon domestication. The phylogeny of 44 Vat-CDS obtained from 21 melon lines revealed gain and loss of leucine-rich-repeat domains along diversification. Altogether, we revealed the high putative recognition scale offered in melon based on a combination of SNPs, number of leucine-rich-repeat domains within each homolog and number of homologs within each cluster that might jointly confer resistance to a large pest and pathogen spectrum. Based on our findings, we propose possible avenues for breeding programs