Expression of ZmHDZ4, a Maize Homeodomain-Leucine Zipper I Gene, Confers Tolerance to Drought Stress in Transgenic Rice

Overexpression of the class I homeodomain transcription factor TaHDZipI‐5 increases drought and frost tolerance in transgenic wheat

“…These data, using T 2 plants, suggested approximately fivefold to eightfold enhancement of drought tolerance in both transgenic lines compared to control plants (Figure a). This observation is in contradiction with that obtained for Oshox22 , overexpressed in transgenic rice (Zhang et al ., ), but correlates with the data obtained for Zmhdz4 , overexpressed in transgenic Arabidopsis and rice (Wu et al ., ). For these discrepancies, we offer the following explanation.…”

“…A series of CDS deletions encoding truncated variants of TaHDZipI‐5 were generated, and the constructs were transformed in yeast cells to detect transactivation activity. Similar to Zmhdz4 (Wu et al ., ) and Oshox22 (Zhang et al ., ), TaHDZipI‐5 was found to contain an AD at the C‐terminal region of the protein (Figure a), which is a highly conserved sequence in homologous proteins from various grasses (Figure b).…”

“…In contrast, overexpression of the similar ZmHDZ4 gene (HD-Zip I c-clade) from maize in transgenic rice enhanced plant tolerance to drought, despite an increased sensitivity to ABA. ZmHDZ4-expressing transgenic plants had a lower relative electrolyte leakage, lower malondialdehyde levels and increased proline contents under drought compared to wildtype (WT) plants (Wu et al, 2016). All of these changes could potentially contribute to enhanced drought tolerance.…”

“…The effect of overexpression of HD‐Zip TFs on the ability of transgenic plants to survive severe stress conditions has also been demonstrated (Bhattacharjee et al ., ; Cabello et al ., ; Cabello and Chan, ; Kovalchuk et al ., ; Wu et al ., ; Zhang et al ., ). For instance, overexpression of the Oshox22 and Oshox24 genes (HD‐Zip I γ‐clade) in transgenic rice and Arabidopsis led to an increased ABA content and increased sensitivity to drought and high salinity (Bhattacharjee et al ., , ; Zhang et al ., ).…”

“…Homeodomain–leucine zipper class I TFs were isolated from a variety of species such as Arabidopsis thaliana (Ariel et al ., ; Schena and Davis, ), resurrection plant Craterostigma plantagineum (Deng et al ., ; Frank et al ., ), sunflower (Cabello and Chan, ; Cabello et al ., ), rice (Agalou et al ., ), maize (Zhao et al ., ) and wheat (Harris et al ., ; Lopato et al ., ). Some of these TFs have been reported to respond to various abiotic stresses on transcriptional and/or post‐translational levels (Bhattacharjee et al ., ; Harris et al ., ; Kovalchuk et al ., ; Olsson et al ., ; Wu et al ., ; Zhao et al ., ). For instance, transcription of Athb7 and Athb12 from Arabidopsis was induced by elevated levels of abscisic acid (ABA) and by water deficiency (Olsson et al ., ; Söderman et al ., ).…”