Nitrogen Deficiency Outperforms Water Stress in Triggering Strigolactone-Dependent Responses in Maize

Area of Science:

• Plant Biology
• Molecular Plant Science
• Agricultural Science

Background:

• Strigolactones (SLs) are plant hormones regulating various developmental processes and stress responses.
• Understanding SLs' role in crop adaptation to abiotic stress is vital for food security.

Purpose of the Study:

• To investigate the role of strigolactones in maize response to nitrogen and water limitation.
• To compare the physiological and molecular responses of an SL-biosynthesis mutant (zmccd8) and wild-type (WT) maize.

Main Methods:

• Maize seedlings (zmccd8 mutant and WT) were grown under nutrient and water limitation.
• Analyses included plant growth, pigment accumulation, gene expression, and root transcriptomics.
• Comparative analysis between mutant and WT under different stress conditions.

Main Results:

• The zmccd8 mutant showed impaired leaf senescence and nutrient remobilization under nitrogen deficiency.
• Nitrogen deficiency induced significant transcriptional changes in WT, largely absent in the mutant.
• Water stress elicited only minor SL-dependent regulation, with limited genotypic differences.

Conclusions:

• Strigolactones play a predominant, stress-specific role in maize acclimatization to nitrogen deficiency.
• SLs coordinate senescence, nutrient remobilization, root architecture, and gene expression for stress adaptation.
• SLs contribute marginally to water-stress acclimatization, highlighting their nuanced role in plant plasticity.