R. Haïcour - Academia.edu (original) (raw)

Papers by R. Haïcour

Plant Cell, Tissue and Organ Culture, 1996

Mannopine and cucumopine strains of Agrobacterium rhizogenes were used for genetic transformation... more Mannopine and cucumopine strains of Agrobacterium rhizogenes were used for genetic transformation in two cultivars of potato (Solanum tuberisum L.). An overnight pretreatment of internodes with a-naphthaleneacetic acid prior to bacterial infection was found to strongly inhibit shoot formation. On the contrary, infection with bacterial strains enhanced the frequency of shoot formation, compared with the controls, except for the strain

Plant Cell Reports, 2001

Protoplast culture and plant regeneration of the dessert banana cultivar Grande Naine (Musa spp.,... more Protoplast culture and plant regeneration of the dessert banana cultivar Grande Naine (Musa spp., Cavendish subgroup AAA) were achieved through somatic embryogenesis. Protoplasts were isolated from cell suspensions at a yield of 3×10 7 protoplasts/ml packed cell volume (0.5 g). For the induction of cell divisions, two banana cell suspensions, SF265 (AA) and IRFA903 (AA), were used as feeder layers. SF265 (AA) was found to be more efficient for inducing cell divisions than IRFA903 (AA). The first embryogenic cell suspensions were established from protoplast-derived microcalli. The transfer of microcalli and protoplast-derived cell suspensions onto regeneration medium containing plant growth regulators slightly increased the number of embryos relative to those maintained on a feeder layer with growth regulators. Plant regeneration was achieved in the same regeneration medium.

Theoretical and Applied Genetics, 1989

Somatic hybrid plants between eggplant (Solanum melongena) and Solanum torvum have been produced ... more Somatic hybrid plants between eggplant (Solanum melongena) and Solanum torvum have been produced by the electrofusion of mesophyll protoplasts in a movable multi-electrode fusion chamber. Using hair structure as a selection criteria, we identified a total of 19 somatic hybrids, which represented an overall average of 15.3% of the 124 regenerated plants obtained in the two fusion experiments. Several morphological traits were intermediate to those of the parents, including trichome density and structure, height, leaf form and inflorescence. Cytological analyses revealed that the chromosome numbers of the somatic hybrids approximated the expected tetraploid level (2n=4x=48). Fifteen hybrid plants were homogeneous and had relatively stable chromosome numbers (46-48), while four other hybrids had variable chromosome numbers (35-48) and exhibited greater morphological variation. The hybridity of these 19 somatic hybrid plants was confirmed by analyses of phosphoglucomutase (Pgm) and esterase zymograms.

Applications of biotechnologies to bananas breeding Conference Paper

Biotechnology in Agriculture and Forestry, 1996

The cultivated potato (Solanum tuberosum L.) is a tetraploid (2n = 4x = 48) and is thought to hav... more The cultivated potato (Solanum tuberosum L.) is a tetraploid (2n = 4x = 48) and is thought to have derived from a primitive diploid species, Solanum stenotomum (2n = 2x = 24). Since tetraploids are more vigorous and more productive, the other degrees of ploidy have been progressively eliminated. The outcome of crosses between tetraploid parental lines is often unpredictable. Since the parents are highly heterozygous, the Fx usually shows a large genetic variation for a number of characteristics, diminishing the chance of finding a new variety. In addition, breeding efforts may be hampered by the fact that sexual incompatibility and male sterility can also occur between and within potato parental lines.

Deep metagenomic shotgun sequencing has emerged as a powerful tool to interrogate composition and... more Deep metagenomic shotgun sequencing has emerged as a powerful tool to interrogate composition and function of complex microbial communities. Computational approaches to assemble genome fragments have been demonstrated to be an effective tool for de novo reconstruction of genomes from these communities. However, the resultant "genomes" are typically fragmented and incomplete due to the limited ability of short-read sequence data to assemble complex or low-coverage regions. Here, we use single-molecule, real-time (SMRT) sequencing to reconstruct a high-quality, closed genome of a previously uncharacterized Corynebacterium simulans and its companion bacteriophage from a skin metagenomic sample. Considerable improvement in assembly quality occurs in hybrid approaches incorporating short-read data, with even relatively small amounts of longread data being sufficient to improve metagenome reconstruction. Using short-read data to evaluate strain variation of this C. simulans in its skin community at single-nucleotide resolution, we observed a dominant C. simulans strain with moderate allelic heterozygosity throughout the population. We demonstrate the utility of SMRT sequencing and hybrid approaches in metagenome quantitation, reconstruction, and annotation. IMPORTANCE The species comprising a microbial community are often difficult to deconvolute due to technical limitations inherent to most short-read sequencing technologies. Here, we leverage new advances in sequencing technology, single-molecule sequencing, to significantly improve reconstruction of a complex human skin microbial community. With this long-read technology, we were able to reconstruct and annotate a closed, high-quality genome of a previously uncharacterized skin species. We demonstrate that hybrid approaches with short-read technology are sufficiently powerful to reconstruct even single-nucleotide polymorphism level variation of species in this a community.

Theoretical and Applied Genetics, 1989

Plant Cell, Tissue and Organ Culture, 2005

Optimization of protoplast fusion parameters is a prerequisite for the establishment of somatic f... more Optimization of protoplast fusion parameters is a prerequisite for the establishment of somatic fusion technology for banana breeding. In the present investigations, we compared the most frequently used fusion methods: the electrofusion technique and chemical procedure (polyethylene glycol). With regard to frequency of binary fusion, protoplast fusion with the fusogen polyethylene glycol was best. Conversely, electric fusion was found to be better with respect to mitotic activities, somatic embryogenesis and plantlet regeneration rate. Abbreviations: 2,4-D D-2,4-dichlorophenoxyacetic acid; BA-benzylaminopurine; CIRAD-Center for International Cooperation in Agricultural Research for Development; IAA-indole-3-acetic acid; MES-2-(N-morpholino) ethanesulfonic acid; NAAa-naphthaleneacetic acid; PCV-packed cell volume; PEGpolyethylene glycol

Plant Cell, Tissue and Organ Culture, 2005

Plant Cell Reports, 1993

Suspensions of embryogenic cells of a triploid banana (Musa spp., cv. Bluggoe) were initiated fro... more Suspensions of embryogenic cells of a triploid banana (Musa spp., cv. Bluggoe) were initiated from the uppermost part of meristematic buds, and used as protoplast source. After 20 weeks in culture, the suspension contained a mixture of globular structures or globules and embryogenic cell clusters, as well as single cells. Two types of protoplasts were obtained from embryogenic suspension culture: small (20-30 l.tm) and larger (30-50 gm) protoplasts with a dense cytoplasm and large starch grains respectively. The small protoplasts probably originated from embryogenic cell clusters, and also from pseudocambial cells of globules, while larger protoplasts were probably released from oval starchy cells and those of the globule peripheral area. In co-culture with a suitable feeder, consisting of suspensions of diploid banana cells, the protoplasts of triploid banana reformed the cell wall within 24 h and underwent sustained divisions leading to the formation of small clusters of 2-3 cells within 7 days. The latter developed directly into embryos without passing through an apparent callus phase. 10% of such embryos gave rise to plantlets when subcultured in 2.2 pM 6benzylaminopurine and 2 ~tM 4 amino-3,5,6trichloropicolinic acid for 1 week, before transfer to MS medium containing 10 pM 6-benzylaminopurine. The rest of the embryos underwent intensive direct secondary embryogenesis which could lead to the formation of plantlets with a frequency of up to 50% upon further transfer to hormone-free medium.

Plant Cell …, 1993

1ER. RESUMEN: Suspensiones de células embriogénicas de los bananos triploides (# Musa# spp., cv.&... more 1ER. RESUMEN: Suspensiones de células embriogénicas de los bananos triploides (# Musa# spp., cv.'Bluggoe'), fueron iniciadas a partir de brotes meristemáticos y utilizadas como fuente de protoplastos. Después de 20 semanas, las mismas contenían una mezcla ...

… of Bananas for …, 1993

(French) L'extension de certaines maladies des bananiers a induit la creation de cv. resista... more (French) L'extension de certaines maladies des bananiers a induit la creation de cv. resistants. Les outils de la biotechnologie sont envisages pour completer les methodes classiques d'amelioration des bananiers. 1 systeme fiable de regeneration a partir de ...

Canadian Journal of Botany, 1984

In this article, we analyse the results of the study of morphological characteristics observed in... more In this article, we analyse the results of the study of morphological characteristics observed in various taxons of the urinaria complex regrouped by the authors under the Urinariae subsection of the Linné Urinaria section. By comparing these results with a taxonomic classification based on a previous genetic study, the qualitative analysis has shown that the discriminating characteristics in systematic units of rank equal to or higher than the species mainly belong to the reproductive apparatus. The vegetative apparatus provides only infraspecific characteristics, with the exception of pilosity and the colour of leaves common to the subsection. The quantitative analysis has shown that (i) practically all the information (90–95%) is provided by the plagiotropic branches (their length, the length of their internodes; dimension and number of their leaves) and by the pollen (dimensions); (ii) the various taxons of the subsection exhibit a wide polymorphism but, within the same populati...

Applications of biotechnologies to bananas breeding Conference Paper

Protoplast technology is an important adjunct to conventional plant breeding. The culture of bana... more Protoplast technology is an important adjunct to conventional plant breeding. The culture of banana protoplasts has advanced considerably in recent years through the use of embryogenic cell suspensions as a source of protoplasts, combined with nurse cultures. Protoplast transformation and somatic hybridization have also become feasible techniques to support the genetic improvement of banana. The present discussion reviews the advantages and disadvantages of the use of protoplasts compared with other methods of genetic transformation and conventional sexual hybridization. General protocols for protoplast culture, genetic transformation and somatic hybridization are presented. _____________________________________________________________________________________________________________

Cahiers Agricultures, 1998

Plants have two natural modes of multiplication, i.e. sexual and vegetative as a consequence of p... more Plants have two natural modes of multiplication, i.e. sexual and vegetative as a consequence of propagation via the production of axillary buds, which are copies of the shoot meristem. These buds, after isolation from the mother plant, produce new shoots and plants with the formation of adventitious roots. This type of multiplication occurs irrespective of flowering and sexual reproduction, and results in clonal propagation. Clonal propagation has long been used by man, mainly for multiplying most tuber-bearing plants. Moreover, fruit trees, ornamental plants and many flowers are propagated from cuttings or scions. Although clonal propagation is traditionally used for plant multiplication, new techniques are now available (including tissue culture) that take recent findings on fundamental mechanisms involved in plant embryogenesis and organogenesis into account. The aim of this paper is to summarize the state of the art and review recent progress and prospects concerning clonal prop...

Banana and plantain are staple foods for nearly 400 million people. High-quality dessert bananas ... more Banana and plantain are staple foods for nearly 400 million people. High-quality dessert bananas for export account for about 12% of the total production, whereas the overall production level is severely threatened by diseases and pests such as fungi (Mycosphaerella and Fusarium), nematodes and viruses. Biotechnology could provide efficient solutions to the problem of plant breeding limitations (sterility of most cultivars) and difficulties encountered with plant protection treatments (not economically feasible under low input sustainable systems, and detrimental to the environment). Over the past 10 years, there has been great progress in the development of banana and plantain biotechnologies. Micropropagation of banana is currently achieved industrially, and transgenic banana plants have already been obtained. Due to the sterility of most cultivated edible banana varieties, plant propagation has been achieved traditionally by vegetative multiplication using naturally occurring pla...

Plant Cell, Tissue and Organ Culture, 1996

Plant Cell Reports, 2001

Theoretical and Applied Genetics, 1989

Applications of biotechnologies to bananas breeding Conference Paper

Biotechnology in Agriculture and Forestry, 1996

Theoretical and Applied Genetics, 1989

Plant Cell, Tissue and Organ Culture, 2005

Plant Cell Reports, 1993

Plant Cell …, 1993

… of Bananas for …, 1993

Canadian Journal of Botany, 1984

Applications of biotechnologies to bananas breeding Conference Paper

Cahiers Agricultures, 1998