Exploring Cell Division and Development in Moss: Insights from Physcomitrium patens and Plant Protoplasts

Exploring Cell Division and Development in Moss: Insights from Physcomitrium patens and Plant Protoplasts

Introduction:

Cell division and development are fundamental processes in plant biology, governing growth, patterning, and the establishment of new organismal axes. In this article, we will delve into two fascinating areas of research: the study of oriented cell divisions in Physcomitrium patens (P. patens) and the design of a comprehensive microfluidic and microscopic toolbox for studying plant protoplasts development and physiology.

Physcomitrium patens: A Model for Oriented Cell Divisions in Patterning:

P. patens, a moss species, offers a unique model to study oriented cell divisions in 1D to 3D patterning. This moss exhibits two types of filaments: chloronemata and caulonemata. Chloronemata are slow-growing, photosynthetically active filaments, while caulonemata are rapidly expanding filaments with underdeveloped chloroplasts. Both types of filaments undergo highly polarized tip growth to explore their immediate environment.

One intriguing aspect of P. patens is the transition from chloronemal to caulonemal identity, which is controlled by the plant hormone auxin and a set of conserved transcription factors. The division planes in chloronemata are perpendicular to the growth axis, while those in caulonemata are consistently slanted. The physiological or developmental relevance of the slanted cross walls in caulonemata is yet to be established.

P. patens offers four tissues/life stages where cell division plane orientation and the establishment of new organismal axes can be studied. Protonemata, which consist of chloronemata and caulonemata, exhibit polarized, unidimensional cell expansion at their apex. Division planes in chloronemata are perpendicular to the growth axis, while caulonemata display tilting of the division apparatus, resulting in slanted division planes.

Secondary growth axes can be established within protonemal tissue through branching of subapical cells. Branching is initiated by a subapical cell and is influenced by hormonal and carbon-related signaling. The branching occurs on the apex-directed side of a mother cell and is oriented based on environmental inputs such as gravity and light. Intracellular reorganization and cell polarization occur in the mother cell before visible outgrowth of a new branch.

Protoplasts Development and Physiology: A Microfluidic and Microscopic Toolbox:

Protoplasts, plant cells with their cell walls removed, provide an excellent system to study plant development and physiology in a controlled environment. A recent study introduced a comprehensive microfluidic and microscopic toolbox designed specifically for the ultra-wide spatio-temporal study of plant protoplasts development and physiology.

The toolbox enables the observation of protoplasts with a homogeneous size distribution, allowing for precise measurements and analysis. Protoplasts have an average size of 32 ± 5 µm. The microfluidic setup provides precise control over the culture conditions, enabling researchers to manipulate various factors such as nutrient availability, hormone concentrations, and light exposure.

The microscopic imaging capabilities of the toolbox allow for high-resolution spatio-temporal analysis of protoplast development. This includes monitoring cell division, organelle dynamics, and gene expression patterns. By combining microfluidics and microscopy, researchers can gain valuable insights into the intricate processes occurring within plant protoplasts.

Unique Insights and Actionable Advice:

• 1. Understanding the mechanisms behind oriented cell divisions in moss, as exemplified by P. patens, can provide valuable insights into the development and patterning of more complex plant organisms. Exploring the physiological and developmental relevance of slanted division planes in caulonemata may uncover novel regulatory pathways.

• 2. The microfluidic and microscopic toolbox for studying protoplasts development and physiology offers a powerful experimental system. Researchers can leverage this technology to investigate the impact of various environmental factors, such as nutrient availability and hormone concentrations, on protoplast development. This can provide a deeper understanding of plant growth and response to external cues.

• 3. The combination of microfluidics and microscopy opens up new avenues for studying the spatio-temporal dynamics of cell division, organelle movement, and gene expression within plant protoplasts. This integrated approach allows for precise measurements and observations, facilitating comprehensive analyses of plant development.

Conclusion:

The study of oriented cell divisions in P. patens and the design of a microfluidic and microscopic toolbox for protoplasts development and physiology offer exciting avenues for plant biology research. By unraveling the mechanisms behind cell division and exploring the dynamics of protoplast development, we can gain valuable insights into the fundamental processes that shape plant growth and patterning. Leveraging these insights, researchers can contribute to advancements in agriculture, biotechnology, and our understanding of plant biology as a whole.