PsnWRKY70 Negatively Regulates NaHCO₃ Tolerance in Populus

Area of Science:

• Plant Biotechnology
• Molecular Biology
• Environmental Science

Background:

• Poplar is vital for afforestation in Northeast China, where saline-alkali lands pose challenges.
• Developing salt-tolerant poplar varieties is crucial for effective afforestation in these areas.
• WRKY transcription factors are known to be involved in plant responses to abiotic stress.

Purpose of the Study:

• To investigate the role of the PsnWRKY70 gene in poplar's response to sodium bicarbonate (NaHCO3) stress.
• To assess the genetic stability and stress tolerance of PsnWRKY70 transgenic poplars.
• To identify molecular mechanisms underlying enhanced NaHCO3 tolerance in modified poplar lines.

Main Methods:

• Genetic stability analysis of PsnWRKY70 transgenic poplars at the mRNA level.
• Evaluation of growth and alkali damage index under NaHCO3 stress for gene interference (RE) and overexpression (OE) lines compared to wild-type (WT).
• Biochemical assays (POD activity, MDA content) and transcriptome analysis to understand stress response pathways.

Main Results:

• PsnWRKY70 expression was genetically stable at the mRNA level in transgenic poplars.
• Gene interference (RE) lines showed significantly lower alkali damage index and higher POD activity than WT and OE lines under NaHCO3 stress.
• RE lines exhibited lower MDA content and up-regulated genes involved in cell wall organization and biogenesis pathways, crucial for NaHCO3 stress tolerance.

Conclusions:

• Interference expression of the PsnWRKY70 gene enhances NaHCO3 tolerance in poplar.
• Targeting PsnWRKY70 offers a promising strategy for breeding salt-tolerant poplar trees for saline-alkali land afforestation.
• Understanding the molecular mechanisms, particularly cell wall-related pathways, is key to improving poplar stress resilience.