Overexpression of <italic>Hevea brasiliensis</italic> ethylene response factor <italic>HbERF‐IXc5</italic> enhances growth and tolerance to abiotic stress and affects laticifer differentiation.

Summary: Ethylene response factor 1 (ERF1) is an essential integrator of the jasmonate and ethylene signalling pathways coordinating a large number of genes involved in plant defences. Its orthologue in <italic>Hevea brasiliensis</italic>,<italic> HbERF‐IXc5</italic>, has been assumed to play a major role in laticifer metabolism and tolerance to harvesting stress for better latex production. This study sets out to establish and characterize rubber transgenic lines overexpressing <italic>HbERF‐IXc5</italic>. Overexpression of <italic>HbERF‐IXc5</italic> dramatically enhanced plant growth and enabled plants to maintain some ecophysiological parameters in response to abiotic stress such as water deficit, cold and salt treatments. This study revealed that <italic>HbERF‐IXc5</italic> has rubber‐specific functions compared to <italic>Arabidopsis </italic>ERF1 as transgenic plants overexpressing <italic>HbERF‐IXc5</italic> accumulated more starch and differentiated more latex cells at the histological level. The role of HbERF‐IXc5 in driving the expression of some target genes involved in laticifer differentiation is discussed. [ABSTRACT FROM AUTHOR]