Genetic regulation of the 2D to 3D growth transition in the moss Physcomitrella patens

Wed January 31st, 2018

A team of researchers at the Department of Plant Sciences have used forward genetics, somatic hybridization, and genome sequencing to identify a gene that regulates the two-dimensional (2D) to three-dimensional (3D) growth transition in the moss Physcomitrella patens. This discovery marks the earliest identified transition stage of 2D to 3D growth.

Colonisation of land by plants has been one of the most important events in the history of life on earth, and this transition was most likely enabled by the evolution of 3D growth. Today the diverse morphologies seen across the terrestrial biosphere arise from the differential regulations of 3D growth processes during development.

In many plants 3D growth occurs during the first zygote divisions, so genetic basis can’t be studied. However in mosses, 3D shoot growth is preceded by a 2D filamentous phase and so the genetic regulators controlling the transition from 2D to 3D growth can be identified.

By studying the moss Physcomitrella patens, researchers identified a causative mutation - they found that the NO GAMETOPHORES 1 (PpNOG1) gene promotes the formation of apical initials that are required for the establishment of 3D growth. In mutants lacking PpNOG1 function, apical initial cells specified for 3D growth were not formed. 

PpNOG1 acts as the earliest identified stage of the 2D to 3D transition, possibly through degradation of proteins that suppress 3D growth. The acquisition of NOG1 function in land plants could thus have enabled the evolution and development of 3D morphology.  

Read the full paper by Dr Laura Moody, Prof Steven Kelly, Ester Rabbinowitsch and Prof Jane Langdale here: http://www.cell.com/current-biology/pdf/S0960-9822(17)31685-8.pdf\