Association of specific expansins with growth in Maize leaves is maintained under environmental, genetic and developmental sources of variation

B. Muller (1) , G. Bourdais , B. Reidy , C. Bencivenni , Agnès Massonneau (2) , Pascal Condamine (2) , G. Rolland , G. Conéjéro (3) , Peter Rogowsky (2) , François Tardieu (4)

1 IAC - Institute for Atmospheric and Climate Science [Zürich]
2 RDP - Reproduction et développement des plantes
3 BPMP - Biochimie et Physiologie Moléculaire des Plantes
4 LEPSE - Écophysiologie des Plantes sous Stress environnementaux

We aimed to evaluate whether changes in maize (Zea mays) leaf expansion rate in response to environmental stimuli or developmental gradients are mediated by common or specific expansins, a class of proteins known to enhance cell wall extensibility. Among the 33 maize expansin or putative expansin genes analyzed, 19 were preferentially expressed at some point of the leaf elongation zone and these expansins could be organized into three clusters related to cell division, maximal leaf expansion, and cell wall differentiation. Further analysis of the spatial distribution of expression was carried out for three expansins in leaves displaying a large range of expansion rates due to water deficit, genotype, and leaf developmental stage. With most sources of variation, the three genes showed similar changes in expression and consistent association with changes in leaf expansion. Moreover, our analysis also suggested preferential association of each expansin with elongation, widening, or both of these processes. Finally, using in situ hybridization, expression of two of these genes was increased in load-bearing tissues such as the epidermis and differentiating xylem. Together, these results suggest that some expansins may be preferentially related to elongation and widening after integrating several spatial, environmental, genetic, and developmental cues.

Mots clés: HISTOLOGIE

Mots clés: BIOLOGIE DU DEVELOPPEMENT

Domaines: Biologie végétale

B. Muller, G. Bourdais, B. Reidy, C. Bencivenni, Agnès Massonneau, et al.. Association of specific expansins with growth in Maize leaves is maintained under environmental, genetic and developmental sources of variation. Plant Physiology, 2007, 143 (1), pp.278-290. ⟨10.1104/pp.106.087494⟩. ⟨hal-00412583⟩