Regulatory mechanism underlying plant tip growth inferred from conchocelis growth of the red alga Neopyropia yezoensis

Abstract

A wide range of tip-growing cells in fungi and plants display polarized cell growth, which is an essential cellular process for the form and function of individual cells. Vesicles containing new cell wall components and membranes are secreted into the apical dome, and, coupled with turgor pressure-driven cell, this restricts growth to this limited zone. Understanding the regulatory mechanisms underlying tip growth in land plants has been advanced through the use of three main cell types: moss protonemata, root hairs and pollen tubes of seed plants. The relationship between the signal transduction, ion gradient and cytoskeleton, have been a subject of much interest. In some species of algae that form filamentous cells, cellular processes in tip growth have also been investigated, but their regulatory mechanisms remain unclear. In the macro red alga Neopyropia yezoensis, for which genome information has recently been released, the conchocelis apical cell exhibits tip growth and form the filamentous structure. We established a live-imaging system with high-resolution microscopy to analyze tip growth of N. yezoensis conchocelis. This review addresses recent advances in our understanding of plant tip growth, including algae, as well as evolutionary insights from the use of the conchocelis.