Expansion and adaptive evolution of the

Area of Science:

• Plant genomics
• Evolutionary biology
• Molecular adaptation

Background:

• Mangroves thrive in intertidal zones with extreme environmental conditions.
• WRKY transcription factors (TFs) regulate plant responses to abiotic stressors.
• The mangrove genus Avicennia faces significant environmental challenges.

Purpose of the Study:

• Investigate the landscape and evolutionary patterns of WRKY genes in Avicennia.
• Understand the role of WRKYs in mangrove adaptation to salinity.
• Analyze the expansion and functional divergence of WRKYs in Avicennia marina.

Main Methods:

• Omic data analysis (genomics and transcriptomics).
• Comparative genomic analysis of WRKY gene families.
• Experimental salt gradient exposure and root gene expression profiling.

Main Results:

• Avicennia exhibits a significant expansion of WRKY genes compared to inland relatives.
• Two recent whole-genome duplication (WGD) events contributed to WRKY expansion, with high retention rates.
• Differential expression of WRKY genes under varying salinity levels suggests roles in salt tolerance.
• Interactions between WRKYs and other genes enhance salt tolerance and adaptation.

Conclusions:

• WRKY gene family expansion and diversification are key to Avicennia's adaptation to intertidal zones.
• Whole-genome duplications played a crucial role in shaping the WRKY repertoire in mangroves.
• Understanding WRKYs in Avicennia provides insights into plant adaptation mechanisms to environmental stress.