PdGNC confers drought tolerance by mediating stomatal closure resulting from NO and H₂O₂ production via the direct regulation of PdHXK1 expression in Populus

Abstract

Drought is one of the primary abiotic stresses, seriously implicating plant growth and productivity. Stomata play a crucial role in regulating drought tolerance. However, the molecular mechanism on stomatal movement-mediated drought tolerance remains unclear.Using genetic, molecular and biochemical techniques, we identified that the PdGNC directly activating the promoter of PdHXK1 by binding the GATC element, a hexokinase (HXK) synthesis key gene.Here, PdGNC, a member of the GATA transcription factor family, was greatly induced by abscisic acid and dehydration. Overexpressing PdGNC in poplar (Populus clone 717) resulted in reduced stomatal aperture with greater water-use efficiency and increased water deficit tolerance. By contrast, CRISPR/Cas9-mediated poplar mutant gnc exhibited increased stomatal aperture and water loss with reducing drought resistance. PdGNC activates PdHXK1 (a hexokinase synthesis key gene), resulting in a remarkable increase in hexokinase activity in poplars subjected to water deficit. Furthermore, hexokinase promoted nitric oxide (NO) and hydrogen peroxide (H 2 O 2 ) production in guard cells, which ultimately reduced stomatal aperture and increased drought resistance.Together, PdGNC confers drought stress tolerance by reducing stomatal aperture caused by NO and H 2 O 2 production via the direct regulation of PdHXK1 expression in poplars.

NAC Transcription Factor PwNAC11 Activates ERD1 by Interaction with ABF3 and DREB2A to Enhance Drought Tolerance in Transgenic Arabidopsis

“…Chlorophyll fluorescence is another important parameter reflecting the function of Photosystem II (PSII) and the transfer efficiency of electrons from PSII to PSI [35]. The Fv/Fm ratio and ΦPSII value represent the potential maximum light energy conversion efficiency and actual quantum yield of PSII, respectively [36,37]. However, the delicate photosynthetic system is frequently affected by the external environment, especially drought stress, which can decrease the Fv/Fm ratio and ΦPSII value.…”

Gene Editing for Plant Resistance to Abiotic Factors: A Systematic Review

“…The mutant knockout exhibited increased stomatal opening and water loss with reduced drought tolerance. Thus, it was possible to understand that PdGNC activates PdHXK1 (a key gene of hexokinase synthesis), resulting in a noticeable increase in hexokinase activity in poplars submitted to water deficit which has consequences in tolerance increments [ 124 ].…”

Engineering drought and salinity tolerance traits in crops through CRISPR-mediated genome editing: Targets, tools, challenges, and perspectives

“…Furthermore, the expression of several drought-responsive genes ( GST , DREB ) was severely affected, implying that SlNPR1 has a positive role in tomato drought tolerance. In Populus , CRISPR-based studies of PdNF-YB21 ( Zhou et al., 2020 ) and GNC ( Shen et al., 2021 ) were performed to understand the functions of these TFs in drought-related processes. Similarly, targeting of drought-responsive TFs such as NAC14 from the NAC family ( Liao et al., 2019 ) and ERF83 from the AP2/ERF family ( Jung et al., 2021 ) in rice using CRISPR tools produced drought-sensitive phenotypes, suggesting that both genes are positive regulators of drought-stress tolerance.…”