Hd3a, RFT1 and Ehd1 integrate photoperiodic and drought stress signals to delay the floral transition in rice.
Plants show a high degree of developmental plasticity in response to external cues, including day length and environmental stress. Water scarcity in particular can interfere with photoperiodic flowering, resulting in the acceleration of the switch to reproductive growth in several species, a process called drought escape. However, other strategies are possible and drought stress can also delay flowering, albeit the underlying mechanisms have never been addressed at the molecular level. We investigated these interactions in rice, a short day species in which drought stress delays flowering. A protocol that allows the synchronization of drought with the floral transition was set up to profile the transcriptome of leaves subjected to stress under distinct photoperiods. We identified clusters of genes that responded to drought differently depending on day length. Exposure to drought stress under floral-inductive photoperiods strongly reduced transcription of EARLY HEADING DATE 1 (Ehd1), HEADING DATE 3a (Hd3a) and RICE FLOWERING LOCUS T 1 (RFT1), primary integrators of day length signals, providing a molecular connection between stress and the photoperiodic pathway. However, phenotypic and transcriptional analyses suggested that OsGIGANTEA (OsGI) does not integrate drought and photoperiodic signals as in Arabidopsis, highlighting molecular differences between long and short day model species.
Department of Biosciences, University of Milan, Via Celoria 26, 20133, Milan, Italy.|Department of Agricultural and Environmental Sciences - Production, Territory, Agroenergy, University of Milan, Via Celoria 2, 20133, Milan, Italy.
Francesca
F
Galbiati
Institute of Agricultural Biology and Biotechnology, National Research Council, Via Bassini 15, 20133, Milan, Italy.
Remo
R
Chiozzotto
Institute of Agricultural Biology and Biotechnology, National Research Council, Via Bassini 15, 20133, Milan, Italy.
Franca
F
Locatelli
Department of Agricultural and Environmental Sciences - Production, Territory, Agroenergy, University of Milan, Via Celoria 2, 20133, Milan, Italy.
Alberto
A
Spada
Institute of Agricultural Biology and Biotechnology, National Research Council, Via Bassini 15, 20133, Milan, Italy.
Annamaria
A
Genga
Department of Biosciences, University of Milan, Via Celoria 26, 20133, Milan, Italy.
Fabio
F
Fornara
D055864:Droughts; D035264:Flowers / Q000254:growth & development*; D020869:Gene Expression Profiling; D012275:Oryza / Q000254:growth & development* / Q000378:metabolism; D017440:Photoperiod; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D013312:Stress, Physiological
D010940:Plant Proteins
OsGI; RNA-Sequencing; florigen; photoperiodic flowering