Calmodulin-binding transcription activator (CAMTA) 6 is a key regulator of Na+ homeostasis and salinity stress responses during early germination

In view of the continuous salinization of arable lands world-wide, there is an urgent need to better understand the mechanisms underlying plant responses to salt stress at different stages of their development. We investigated the role of calmodulin (CaM)-binding transcription activator 6 (CAMTA6) under salinity stress during early germination in Arabidopsis. These analyses suggest that ABA signaling is involved in CAMTA6-dependent salt-responsive gene expression, consistent with the ABA hyper-tolerance phenotype and the lack of HKT1 response to ABA and NaCl in the camta6 mutants. In order to study the germination behavior of camta6 mutants in the presence of salt (NaCl), seeds of wild-type (Col-0) and an allele of camta6 mutant (camta6-5) with 0 (control) or 200 mM NaCl.