An endoplasmic reticulum-localized NtHSP70-8 confers drought tolerance in tobacco by regulating water loss and antioxidant capacity

•NtHSP70-8 involvement in drought, ABA and auxin responses in tobacco.•NtHSP70-8 is an endoplasmic reticulum-localized protein and overexpression of NtHSP70-8 enhance the drought tolerance in tobacco.•Overexpression of NtHSP70-8 reduce the water loss of leaves by regulating ABA and IAA signaling pathway.•NtHSP70-8 is involved regulating the antioxidant capacity, possibly caused by the expression of antioxidant-related genes.