TCP transcription factors play important regulatory roles in plantgrowth
and development
[www.sciencedirect.com];
however, their function in response to salt and drought stress in
sea-island cotton (/Gossypium barbadense
[www.sciencedirect.com])
is unknown.

Here,/GbTCP4/expression was induced byabscisic acid
[www.sciencedirect.com]),
drought, and NaCl treatments. Under drought stress, compared to
wild-type (WT)/Arabidopsis
[www.sciencedirect.com],
transgenic/GbTCP4/-overexpressing/Arabidopsis/showed increasedseed
germination
[www.sciencedirect.com],
root length and survival rate; additionally, it was ABA-insensitive at
the germination stage but ABA-sensitive at the seedling stage, showing
reduced stomatal opening and ABA enrichment.

Under salt stress, compared to WT/Arabidopsis/,
transgenic/GbTCP4-/overexpressing/Arabidopsis/showed greater root
length, survival rate, and SPAD value and lower malondialdehyde (MDA)
content. Conversely, under drought or salt stress, virus-induced
gene-silenced/GbTCP4/cotton showed decreased root length, area and
volume and increased MDA content and sensitivity to drought and salt
stress compared with control cotton.

RNA-seq and quantitative real-time PCR analyses showed
that/GbTCP4/affected the transcription levels of genes across multiple
abiotic stress-related metabolic pathways. Furthermore, GbTCP4 activated
the transcription of/GbUVR8/and/GbbHLH130/by binding to their promoters.
These results suggest that GbTCP4 positively regulates drought and salt
stress responses and is a suitable candidate gene for improving plant
drought and salt tolerance.

[www.sciencedirect.com]