Evolutionary Diversification of the Maize Str-like Gene Family Revealed Through Sequence, Structural and Functional...

Area of Science:

• Plant molecular biology
• Evolutionary genomics
• Biochemistry

Background:

• Strictosidine synthases (STRs) are key in plant alkaloid biosynthesis.
• STR-like (STRL) genes in cereals, particularly maize, are poorly understood regarding their evolution and function.
• Previous maize STRL studies focused on identification and expression, but evolutionary constraints and diversification mechanisms require further investigation.

Purpose of the Study:

• To investigate the evolutionary constraints and molecular mechanisms driving the diversification of the maize STR-like (STRL) gene family.
• To integrate evolutionary analyses with structural and expression data for a comprehensive understanding of ZmSTRL genes.
• To identify candidate ZmSTRL genes and structural features for future functional validation.

Main Methods:

• Comparative and phylogenetic analysis of 21 ZmSTRL genes.
• Analysis of sequence divergence, codon usage bias, and selection pressure.
• Protein structural modeling and Gene Ontology (GO) enrichment analysis.
• Tissue-specific quantitative real-time PCR (qRT-PCR) expression analysis.

Main Results:

• Phylogenetic analysis revealed conserved lineages and maize-specific expansion patterns within the ZmSTRL family.
• Codon usage and neutrality analyses indicated heterogeneous evolutionary constraints, suggesting divergence beyond mutational pressure.
• Structural modeling showed conserved catalytic frameworks with localized variations in loop and terminal regions.
• Divergent tissue-specific expression patterns were observed for selected ZmSTRL genes, implying regulatory specialization.

Conclusions:

• The study establishes an evolutionary-constraint-based framework for understanding ZmSTRL diversification in maize.
• ZmSTRL genes exhibit a combination of conserved structural features and localized divergence, contributing to functional specialization.
• The findings highlight potential regulatory specialization and identify specific ZmSTRL genes and structural elements for future functional research.