Confers resistance to low temperatures by limiting chloroplast damage and cell death, thus maintaining growth homeostasis. H2O + NAD(+) = ADP-D-ribose + H(+) + nicotinamide Mostly expressed in leaves, stems and roots, and, to a lower extent, in flowers and siliques. The TIR domain mediates NAD(+) hydrolase (NADase) activity. Self-association of TIR domains is required for NADase activity. Truncated N-terminus.