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Impacts of light and temperature on shoot branching gradient and expression of strigolactone synthesis and signalling genes in rose
Author(s) -
DJENNANE SAMIA,
HIBRANDSAINT OYANT LAURENCE,
KAWAMURA KOJI,
LALANNE DAVID,
LAFFAIRE MICHEL,
THOUROUDE TATIANA,
CHALAIN SÉVERINE,
SAKR SOULAIMAN,
BOUMAZA RACHID,
FOUCHER FABRICE,
LEDUC NATHALIE
Publication year - 2014
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12191
Subject(s) - plant stem , strigolactone , shoot , biology , botany , phloem , axillary bud , gene expression , microbiology and biotechnology , gene , mutant , arabidopsis , genetics , tissue culture , in vitro
Light and temperature are two environmental factors that deeply affect bud outgrowth. However, little is known about their impact on the bud burst gradient along a stem and their interactions with the molecular mechanisms of bud burst control. We investigated this question in two acrotonic rose cultivars. We demonstrated that the darkening of distal buds or exposure to cold (5 °C) prior to transfer to mild temperatures (20 °C) both repress acrotony, allowing the burst of quiescent medial and proximal buds. We sequenced the strigolactone pathway MAX ‐homologous genes in rose and studied their expression in buds and internodes along the stem. Only expressions of RwMAX 1 , RwMAX 2 and RwMAX 4 were detected. Darkening of the distal part of the shoot triggered a strong increase of RwMAX 2 expression in darkened buds and bark‐phloem samples, whereas it suppressed the acropetal gradient of the expression of RwMAX 1 observed in stems fully exposed to light. Cold treatment induced an acropetal gradient of expression of RwMAX 1 in internodes and of RwMAX 2 in buds along the stem. Our results suggest that the bud burst gradient along the stem cannot be explained by a gradient of expression of RwMAX genes but rather by their local level of expression at each individual position.