Thierry Tétu
University of Picardie Jules Verne
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Featured researches published by Thierry Tétu.
Plant Cell Reports | 1992
Benoit Jacq; Thierry Tétu; Rajbir S. Sangwan; Ad De Laat; Brigitte S. Sangwan-Norreel
A simple and reproducible protocol for regeneration of sugarbeet plants from hypocotyl expiants derived from 21 day-old-seedlings has been developed. Expiants were cultured on MS medium containing 0.3 mg/l N6-Benzylaminopurine, 0.1 mg/l Naphthalene Acetic Acid, 50 mg/l adenine and 0.5% (w/v) fructose, 0.5% (w/v) sucrose and 0.5% (w/v) glucose to induce the formation of organogenic calli (2.3% to 46.5% organogenic efficiency, depending on populations). Shoot formation was induced in callus cultures of more than 1600 genotypes. Physiological age affected culture response and different genotypes had different temperature optima for organogenesis. Following transfer of regenerated plants to the greenhouse, DNA determinations were made to study the stability of ploidy. Differences in ploidy were observed in plants derived from both shortterm and long-term callus cultures; diploid true-to-type regenerants were 96% and 83%, respectively, from shortterm and long-term callus cultures.
Plant Science | 2017
Julien Verzeaux; Bertrand Hirel; Frédéric Dubois; Peter J. Lea; Thierry Tétu
Nitrogen cycling in agroecosystems is heavily dependent upon arbuscular mycorrhizal fungi (AMF) present in the soil microbiome. These fungi develop obligate symbioses with various host plant species, thus increasing their ability to acquire nutrients. However, AMF are particularly sensitive to physical, chemical and biological disturbances caused by human actions that limit their establishment. For a more sustainable agriculture, it will be necessary to further investigate which agricultural practices could be favorable to maximize the benefits of AMF to improve crop nitrogen use efficiency (NUE), thus reducing nitrogen (N) fertilizer usage. Direct seeding, mulch-based cropping systems prevent soil mycelium disruption and increase AMF propagule abundance. Such cropping systems lead to more efficient root colonization by AMF and thus a better establishment of the plant/fungal symbiosis. In addition, the use of continuous cover cropping systems can also enhance the formation of more efficient interconnected hyphal networks between mycorrhizae colonized plants. Taking into account both fundamental and agronomic aspects of mineral nutrition by plant/AMF symbioses, we have critically described, how improving fungal colonization through the reduction of soil perturbation and maintenance of an ecological balance could be helpful for increasing crop NUE.
Plant Science | 1996
Shanjun Tu; Thierry Tétu; Rajbir S. Sangwan; Brigitte S. Sangwan-Norreel
Abstract A rapid and efficient regeneration system via somatic embryogenesis has been developed from zygotic embryos of Hyoscyamus niger (black henbane). The effect of 2-(n-morpholino)ethanesulfonic acid (MES), myo-inositol (MI) and different combinations of them with a number of growth regulators on somatic embryogenesis was evaluated. Maximum frequency of direct somatic embryogenesis and germination (30.6%) was achieved after 2–5 weeks by a one-step culture procedure on Murashige and Skoogs (MS) basal medium containing 1 mg/l naphthaleneacetic acid, 2 g/l MI and 0.5 g/l MES. Ploidy level of twenty randomly selected regenerants was determined using flow cytometry. No variation in their ploidy levels was observed. This regeneration system may be of value for application with a microparticle gun and Agrobacterium tumefaciens-mediated genetic transformation of black henbane.
PLOS ONE | 2017
Elodie Nivelle; Julien Verzeaux; David Roger; Fabien Spicher; Jérôme Lacoux; Jose-Edmundo Nava-Saucedo; Manuella Catterou; Thierry Tétu
The use of nitrogen (N) fertilizer and glyphosate-based herbicides is increasing worldwide, with agriculture holding the largest market share. The agronomic and socioeconomic utilities of glyphosate are well established; however, our knowledge of the potential effects of glyphosate applied in the presence or absence of long-term N fertilization on microbial functional activities and the availability of soil nutrients remains limited. Using an ex situ approach with soils that did (N+) or did not (N0) receive synthetic N fertilization for 6 years, we assessed the impact of different rates (no glyphosate, CK; field rate, FR; 100 × field rate, 100FR) of glyphosate application on biological and chemical parameters. We observed that, after immediate application (1 day), the highest dose of glyphosate (100FR) negatively affected the alkaline phosphatase (AlP) activity in soils without N fertilization history and decreased the cation exchange capacity (CEC) in N0 compared to CK and FR treatments with N+. Conversely, the 100FR application increased nitrate (NO3-) and available phosphorus (PO43-) regardless of N fertilization history. Then, after 8 and 15 days, the N+\100FR and N+\FR treatments exhibited the lowest values for dehydrogenase (DH) and AlP activities, respectively, while urease (URE) activity was mainly affected by N fertilization. After 15 days and irrespective of N fertilization history, the FR glyphosate application negatively affected the degradation of carbon substrates by microbial communities (expressed as the average well color development, AWCD). By contrast, the 100FR treatment positively affected AWCD, increasing PO43- by 5 and 16% and NO3- by 126 and 119% in the N+ and N0 treatments, respectively. In addition, the 100FR treatment resulted in an increase in the average net nitrification rate. Principal component analysis revealed that the 100FR glyphosate treatment selected microbial communities that were able to metabolize amine substrates. Overall, the lack of N fertilization in the 6 past years combined with the highest glyphosate application rate (100FR) induced the highest values of AWCD, functional diversity, NO3-, PO43- and nitrification. We concluded that the intensive use of N fertilization for 6 years may change the non-target effects of glyphosate application on enzyme activities. The functional activities, nitrification and nutrient contents were increased by glyphosate only when applied at 100 times the field application rate.
PLOS ONE | 2016
Hazzar Habbib; Julien Verzeaux; Elodie Nivelle; David Roger; Jérôme Lacoux; Manuella Catterou; Bertrand Hirel; Frédéric Dubois; Thierry Tétu
A two-year experiment was conducted in the field to measure the combined impact of tilling and N fertilization on various agronomic traits related to nitrogen (N) use efficiency and to grain yield in maize cultivated in the presence of a cover crop. Four years after conversion to no-till, a significant increase in N use efficiency N harvest index, N remobilization and N remobilization efficiency was observed both under no and high N fertilization conditions. Moreover, we observed that grain yield and grain N content were higher under no-till conditions only when N fertilizers were applied. Thus, agronomic practices based on continuous no-till appear to be a promising for increasing N use efficiency in maize.
Sustainability | 2011
Bertrand Hirel; Thierry Tétu; Peter J. Lea; Frédéric Dubois
Plant and Cell Physiology | 2006
Jean-Xavier Fontaine; Francesca Saladino; Caterina Agrimonti; Magali Bedu; Thérèse Tercé-Laforgue; Thierry Tétu; Bertrand Hirel; Francesco Maria Restivo; Frédéric Dubois
Plant Breeding | 1993
B. Jaco; Thierry Tétu; R. S. Sangwani; A. De Laat; Brigitte S. Sangwan-Norreel
Applied Soil Ecology | 2016
Elodie Nivelle; Julien Verzeaux; Hazzar Habbib; Yakov Kuzyakov; Guillaume Decocq; David Roger; Jérôme Lacoux; Jérôme Duclercq; Fabien Spicher; Jose-Edmundo Nava-Saucedo; Manuella Catterou; Frédéric Dubois; Thierry Tétu
Geoderma | 2016
Julien Verzeaux; Abdelrahman Alahmad; Hazzar Habbib; Elodie Nivelle; David Roger; Jérôme Lacoux; Guillaume Decocq; Bertrand Hirel; Manuella Catterou; Fabien Spicher; Frédéric Dubois; Jérôme Duclercq; Thierry Tétu