Table 2.

Transcriptional factors in response to heavy metal stresses.

Family	Genes	Heavy Metals	Function	Number of Phosphorylation Sites	Reference
bZIP	RsbZIP010	Cd, Cr and Pb	RsbZIP010 exhibited downregulated expression under Cd, Cr and Pb stresses.		[46]
	GubZIP	Cd	GubZIPs were expressed specifically in different tissues under cadmium stress		[47]
	LOC_Os02g52780/OsbZIP23	Cd	LOC_Os02g52780 related to the tolerance of rice to Cd stress and affected Cd accumulation in rice grains.	39	[48]
	BjCdR15	Cr	TGA3 elevates LCD expression and H2S production to bolster Cr6+ tolerance in Arabidopsis.	35	[49,50,51]
	BnbZIP2 BnbZIP3	Cd	Over expression of BnbZIP2 exhibited more sensitivity to drought and heavy metal Cd stress.	0/44	[52]
	ABI5	Cd	ABI5 interacts with MYB49 and prevented its binding to the downstream genes, resulting in inactivation of IRT1 and reduced Cd uptake.	46	[53]
	bZIP19,23	Zn	Zinc sensors to control plant zinc status.	25/17	[54,55]
MYB	OsMYB45	Cd	Under Cd stress, OsMYB45 is highly expressed. Mutation of OsMYB45 resulted in hypersensitivity to Cd treatment.	37	[56]
	SbMYB15	Cd, Ni	Overexpression of SbMYB15 conferred. Cadmium and nickel tolerance in transgenic tobacco	45	[57]
	AtMYB4	Cd	MYB4 regulates Cd-tolerance via the coordinated activity of improved anti-oxidant defense systems and through the enhanced expression of PCS1 and MT1C under Cd-stress in Arabidopsis.	40	[58]
	JrMYB2	Cd	JrMYB2 acts as an upstream regulator of JrVHAG1 to improve CdCl2 stress tolerance stress tolerance.		[59]
	AtMYB72	Zn, Fe	The Arabidopsis MYB72 knockout mutant was more sensitive to excess Zn or Fe deficiency than wild-type.	43	[60]
	OsARM1	As	OsARM1 regulates arsenic absorption and root-to-shoot translocation.	19	[61]
	AtMYB40	As	AtMYB40 enhances plant As (V) tolerance and reduces As(V) uptake.	28	[62]
	DwMYB2	Fe	The translocation of iron from root to shoot is affected by the DwMYB2.	39	[63]
WRKY	RsWRKY	Cd	RsWRKY transcripts were significantly elevated under Cd and Pb treatments.		[64]
	AtWRKY12	Cd	WRKY12 represses GSH1 expression to negatively regulates cadmium tolerance in Arabidopsis.	31	[65]
	AtWRKY13	Cd	Activates PDR8 expression to positively regulate cadmium tolerance in Arabidopsis.	49	[66]
	AtWRKY13	Cd	WRKY13 activation of DCD during cadmium stress.	49	[67]
	GmWRKY142	Cd	GmWRKY142 confers cadmium resistance by upregulating the cadmium tolerance 1-like genes.	54	[68]
	AtWRKY47	Al	A WRKY transcription factor confers aluminum tolerance via regulation of cell wall modifying genes.	63	[69]
	AtWRKY6	As	WRKY6 transcription factor restricts arsenate uptake and transposon activation in Arabidopsis.	66	[70]
HSF	SaHsfA4c	Cd	The expression of SaHsfA4c was induced by cadmium and enhanced Cd tolerance by ROS -scavenger activities and shock proteins expression.	39	[71,72]
	TaHsfA4a OsHsfA4a	Cd	HsfA4a of wheat and rice confers Cd tolerance by upregulating MT gene expression.	46	[73]
	PvBip1	Cd	HSF/HSP participates in the reconstruction of protein conformation and improves intracellular homeostasis to increase cadmium tolerance.	64	[74]
	HSF1A	Cd	HsfA1a upregulates melatonin biosynthesis to confer cadmium tolerance in tomato plants.	55	[75]
	PuHSFA4a	Zn	PuHSFA4 activates the antioxidant system and root development–related genes and directly targets PuGSTU17 and PuPLA.	39	[76]
Others	AemNAC2	Cd	Overexpression of AemNAC2 led to reduced cadmium concentration.	52	[77]
	VuNAR1	Al	VuNAR1 regulates Al resistance by regulating cell wall pectin metabolism via directly binding to the promoter of WAK1 and inducing its expression.	24	[78]
	ZAT6	Cd	ZAT6 coordinately activates PC synthesis–related gene expression and directly targets GSH1 to positively regulate Cd accumulation and tolerance in Arabidopsis.	40	[79]
	AtbHLH104 AtbHLH38 AtbHLH39	Cd	AtbHLHs positively regulates genes involved in heavy metal absorption and detoxification.	27/27/35	[80,81]
	HIPP22	Cd	MYB49 binds to the promoter regions of the HIPP22 and HIPP44, resulting in upregulation Cd accumulation.	14	[76]
	PvERF15	Cd	PvERF15 and PvMTF-1 form a cadmium-stress transcriptional pathway.	44	[82]