Three-dimensional growth: a developmental innovation that facilitated plant terrestrialization

Area of Science:

• Evolutionary developmental biology
• Plant science
• Algal biology

Background:

• The aquatic-to-terrestrial transition of plants ~470 million years ago was a pivotal evolutionary event.
• Charophyte green algae, the closest relatives to land plants, exhibit diverse body plans evolved from unicellular to complex multicellular forms.
• Early plant evolution involved 1D and 2D growth strategies, leading to filaments, mats, and branches.

Purpose of the Study:

• To review the evolving developmental complexities from early Charophytes to the first land plants.
• To investigate the independent evolution of three-dimensional (3D) apical growth in brown algae.
• To understand the developmental innovations facilitating terrestrial colonization.

Main Methods:

• Review of existing literature on plant and algal evolution.
• Analysis of developmental strategies in early divergent Charophytes.
• Comparative investigation of 3D apical growth in green and brown algal lineages.

Main Results:

• Charophytes developed diverse body plans using 1D and 2D growth before the land transition.
• The evolution of 3D apical growth with multi-faced apical cells was crucial for adapting to terrestrial environments.
• 3D apical growth evolved convergently in brown algae, separate from the green lineage.

Conclusions:

• The development of 3D growth was a fundamental innovation for plant terrestrialization.
• Convergent evolution of 3D apical growth highlights its adaptive significance in different lineages.
• Understanding these early developmental shifts provides insights into plant colonization of diverse environments.