A key role of transcription factor in grafted cucumbers exhibits salt tolerance in crops

Affecting about 1 billion square hectometres worldwide, soil salinity significantly inhibits crop growth. Plants counter this through signaling pathways involving molecules such as H₂oh₂ and ABA. NAC transcription factors, unique to plants, play important roles in regulating these stress responses.

In grafted vegetables such as cucumbers on cucurbit rootstocks, these factors appear to be important for improving salt tolerance by modulating stomatal closure. However, the detailed regulatory role of NAC factors in this context remains unclear, highlighting an important area for research.

A study Published Inside Horticultural research „CmoNAC1 in pumpkin rootstocks enhances salt tolerance of grafted cucumbers by binding to the promoters of CmoRBOHD1, CmoNCED6, CmoAKT1;2 and CmoHKT1;1 to regulate H₂oh₂ABA Signaling and K+/Na+ Homeostasis” provides new insights into improving salt tolerance in cucumbers and valuable hints for molecular breeding of salt-tolerant pumpkin rootstocks.

Initially, homologues of the enzyme NCED were identified in pumpkin, CmoNCED6 emerged as the key gene for ABA synthesis under salt stress. Analysis of transcription factors binding to the promoters of CmoRBOHD1 and CmoNCED6 identified CmoNAC1 as a significant regulator.

Root transformation experiments demonstrated that CmoNAC1 knockout resulted in reduced H₂oh₂ABA content and K⁺/ That⁺ ratio in grafted cucumbers, while overexpression had the opposite effect, confirming the role of CmoNAC1 in increasing salt tolerance.

Further research showed that CmoNAC1 affects the production of H₂oh₂ and ABA in grafted cucumber leaves and roots by regulating the expression of CsaRBOHD, CsaNCED3, CmoRBOHD1 and CmoNCED6, thereby regulating physiological responses under salt stress.

In addition, this study confirmed the important role of CmoNCED6 in salt tolerance of grafted cucumbers, specifically influencing ABA signal transduction, stomatal regulation and ion balance regulation. CmoNAC1 can bind to the promoters of CmoRBOHD1, CmoNCED6, CmoAKT1;2, ​​and CmoHKT1;1, thereby regulating their expression.

This binding was confirmed using yeast one-hybrid, luciferase, and electrophoretic mobility shift assays. A regulatory effect of CmoNAC1 on K+/Na+ transporters under salt stress was established, showing that knockout and overexpression of CmoNAC1 significantly modulated the expression of key transporters.

In conclusion, this research demonstrated that CmoNAC1 is an important transcription factor in grafted cucumbers, contributing to salt tolerance by regulating H.₂oh₂ and ABA signaling and K⁺/ That⁺ Homeostasis. This finding adds valuable knowledge to the field of plant biology and agricultural practices, particularly in the context of increasing crop resilience to environmental stresses such as soil salinity.