Polyploidization mechanisms: Temperature environment can induce diploid gamete formation in Rosa sp.

Pecrix Yann, Rallo Géraldine, Folzer Hélène, Cigna Mireille, Gudin Serge, Le Bris Manuel. 2011. Polyploidization mechanisms: Temperature environment can induce diploid gamete formation in Rosa sp.. Journal of Experimental Botany, 62 (10) : 3587-3597.

Quartile : Q1, Sujet : PLANT SCIENCES

Résumé : Polyploidy is an important evolutionary phenomenon but the mechanisms by which polyploidy arises still remain underexplored. There may be an environmental component to polyploidization. This study aimed to clarify how temperature may promote diploid gamete formation considered an essential element for sexual polyploidization. First of all, a detailed cytological analysis of microsporogenesis and microgametogenesis was performed to target precisely the key developmental stages which are the most sensitive to temperature. Then, heat-induced modifications in sporad and pollen characteristics were analysed through an exposition of high temperature gradient. Rosa plants are sensitive to high temperatures with a developmental sensitivity window limited to meiosis. Moreover, the range of efficient temperatures is actually narrow. 36 °C at early meiosis led to a decrease in pollen viability, pollen ectexine defects but especially the appearance of numerous diploid pollen grains. They resulted from dyads or triads mainly formed following heat-induced spindle misorientations in telophase II. A high temperature environment has the potential to increase gamete ploidy level. The high frequencies of diplogametes obtained at some extreme temperatures support the hypothesis that polyploidization events could have occurred in adverse conditions and suggest polyploidization facilitating in a global change context.

Mots-clés libres : Diploid gamete, Meiosis, Microsporogenesis, Pollen viability, Polyploidization, Rosa sp., Temperature

Auteurs et affiliations

• Pecrix Yann, Institut méditerranéen d'écologie et de paléoécologie (FRA) ORCID: 0000-0002-6537-3145
• Rallo Géraldine, Institut méditerranéen d'écologie et de paléoécologie (FRA)
• Folzer Hélène, Institut méditerranéen d'écologie et de paléoécologie (FRA)
• Cigna Mireille, Institut méditerranéen d'écologie et de paléoécologie (FRA)
• Gudin Serge, Institut méditerranéen d'écologie et de paléoécologie (FRA)
• Le Bris Manuel, Institut méditerranéen d'écologie et de paléoécologie (FRA) - auteur correspondant

Source : Cirad-Agritrop (https://agritrop.cirad.fr/600448/)

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