Table 1.
Cotton WRKY genes regulated abiotic stresses.
| WRKY Gene (Sub Group) | Stress | Cellular Localization | Expression in Plant | Traits Regulated | Reference |
|---|---|---|---|---|---|
| GbWRKY1 (I) | Reduced Phosphorus starvation, and tolerance to drought and salt stresses | Nucleus | Overexpressed in Arabidopsis and cotton | Overexpressing lines reduced the accumulation of anthocyanin and enhanced the activity of phosphatase, MDA content, ion leakage and root inhibition | [68,109] |
| GhWRKY3 (I) | Expressed under drought, salt and low temperature | Nucleus | NA | NA | [110] |
| GarWRKY5 (III) | Enhanced salt tolerance | NA | Silenced in cotton and overexpressed in Arabidopsis | Overexpressing lines exhibited higher activities of SOD, POD and enhanced root length | [55] |
| GhWRKY6 | Regulated drought and salt stresses | NA | Silenced in cotton and overexpressed in Arabidopsis | Overexpressing plants showed shorter root length, larger stomatal aperture, increased H2O2 and MDA level, reduced proline accumulation and participated in ABA signaling pathway | [111] |
| GhWRKY6-like | Improved salt and drought tolerance | Nucleus | Overexpressed in Arabidopsis and silenced in cotton | In overexpressing lines, MDA and H2O2 content were reduced and proline, SOD and POD contents were increased. Expression pattern of ABA signaling pathway genes was also reported higher in overexpressing lines. | [58] |
| GhWRKY15 (IId) | Increased resistant against wounding Viral and fungal infection | Nucleus | Overexpressed in Tobacco | Increased POD, APX and expression of stress related genes | [12] |
| GhWRKY17 (IId) | Enhanced drought and salt sensitivity | Nucleus | Overexpressed in Nicotiana benthamiana | Reduced root length, seed germination, stomatal closure, chlorophyll content and expression pattern of marker genes involved in ABA signaling pathway Increased water loss rate, electrolyte leakage and accumulation of O2−, H2O2, MDA content |
[48] |
| GhWRKY25 (I) | Enhanced salt tolerance but reduced drought tolerance and plant defense against fungal pathogen | Nucleus | Overexpressed in Nicotiana benthamiana | Increased MDA, O2−, and H2O2 content Decreased SOD, POD and CAT activities, inhibited root length under drought stress |
[56] |
| GhWRKY27a (III) | Reduced drought tolerance | Nucleus | Overexpressed in Nicotiana benthamiana and silenced in cotton | Overexpressing lines exhibited short roots, closed stomata, high content O2−, and H2O2, and low level of drought related genes expression | [49] |
| GhWRKY33 (III) | Reduced drought tolerance | Nucleus | Overexpressed in Arabidopsis | Inhibited seed germination, early seedling growth and root length, reduced sensitivity to ABA | [24] |
| GhWRKY34 (III) | Enhanced salt tolerance | Nucleus | Overexpressed in Arabidopsis | Seed germination, root length, chlorophyll content and expression pattern of stress related genes was higher | [42] |
| GhWRKY39 (IId) | Enhanced resistance to pathogen infection and salinity | Nucleus | Overexpressed in Nicotiana benthamiana | Reduced hydrogen peroxide accumulation and increased the level of APX, CAT, GST and SOD | [112] |
| GhWRKY39-1 (IId) | Enhanced resistance to pathogen infection and salinity | Nucleus | Overexpressed in Nicotiana benthamiana | Enhanced root length and expression pattern of SOD, GST, APX, and CAT. Decreased H2O2 content |
[57] |
| GhWRKY40 (IIa) | Enhanced tolerance against wounding | Nucleus | Overexpressed in Nicotiana benthamiana | Decreased level of O2− and H2O2
Transcript level of JA and SA associated genes in overexpressing plants was decreased |
[71] |
| GhWRKY41 (III) | Enhanced drought and salinity tolerance | Nucleus | Overexpressed in Nicotiana benthamiana | Reduced MDA, H2O2 content and ABA dependent stomatal opening. Accumulated increased level of SOD, POD and CAT | [41] |
| GhWRKY42 (IId) | Induced drought and salinity stress | Nucleus | Overexpressed in Arabidopsis | Increased senescence | [33] |
| GhWRKY68 (IIc) | Reduced drought and salt tolerance | Nucleus | Overexpressed in Nicotiana benthamiana | Stomatal opening, O2−, H2O2, and MDA content were increased. Reduced total chlorophyll, CAT, SOD and POD content, root length, expression pattern of ABA-dependent pathway genes |
[113] |
| GhWRKY91 (IIe) | Enhanced drought tolerance and delayed senescence | NA | Overexpressed in Arabidopsis | Expression pattern of marker genes involved in drought tolerance was significantly higher. | [77] |
Footnote: ABA = Abscisic acid, APX = Ascrobate peroxidase, CAT = Catalase, GST = Glutathione peroxidase, MDA = Malondialdehyde, NA = Not applicable, POD = Peroxidase, SOD = Superoxide dismutase.