Plant Vascular Cell Division Is Maintained by an Interaction between PXY and Ethylene Signalling
Open Access
- 15 November 2012
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLoS Genetics
- Vol. 8 (11), e1002997
- https://doi.org/10.1371/journal.pgen.1002997
Abstract
The procambium and cambium are meristematic tissues from which vascular tissue is derived. Vascular initials differentiate into phloem towards the outside of the stem and xylem towards the inside. A small peptide derived from CLV-3/ESR1-LIKE 41 (CLE41) is thought to promote cell divisions in vascular meristems by signalling through the PHLOEM INTERCALLATED WITH XYLEM (PXY) receptor kinase. pxy mutants, however, display only small reductions in vascular cell number, suggesting a mechanism exists that allows plants to compensate for the absence of PXY. Consistent with this idea, we identify a large number of genes specifically upregulated in pxy mutants, including several AP2/ERF transcription factors. These transcription factors are required for normal cell division in the cambium and procambium. These same transcription factors are also upregulated by ethylene and in ethylene-overproducing eto1 mutants. eto1 mutants also exhibit an increase in vascular cell division that is dependent upon the function of at least 2 of these ERF genes. Furthermore, blocking ethylene signalling using a variety of ethylene insensitive mutants such as ein2 enhances the cell division defect of pxy. Our results suggest that these factors define a novel pathway that acts in parallel to PXY/CLE41 to regulate cell division in developing vascular tissue. We propose a model whereby vascular cell division is regulated both by PXY signalling and ethylene/ERF signalling. Under normal circumstances, however, PXY signalling acts to repress the ethylene/ERF pathway. Plants transport water and nutrients throughout their bodies using a specialised vascular system. Vascular tissue is also responsible for providing structural support to plants; for example, wood is made up of specialised vascular cells. Consequently, the vascular system constitutes the majority of plant biomass. Chemicals from plant biomass could be used to make the next generation of biofuels in order to reduce dependence on fossil fuels. Vascular tissue is derived from a group of dividing cells present in a structure called the procambium, but mechanisms controlling cell division in this structure remain poorly understood. Understanding the events that occur in the procambium may help us to understand how we can best utilise plants for increased plant biomass, for example, for biofuel and wood production. We have identified a number of genes that regulate cell division in the procambium that are controlled by the gaseous plant hormone ethylene. We show that ethylene signalling, in turn, interacts with PXY, a gene encoding a signalling component that also controls vascular cell division. Our results demonstrate that the interaction between ethylene and PXY signalling is responsible for maintaining the plant vascular system.Keywords
This publication has 66 references indexed in Scilit:
- From thin to thick: major transitions during stem developmentTrends in Plant Science, 2012
- Strigolactone signaling is required for auxin-dependent stimulation of secondary growth in plantsProceedings of the National Academy of Sciences of the United States of America, 2011
- Multiple feedback loops through cytokinin signaling control stem cell number within the Arabidopsis shoot meristemProceedings of the National Academy of Sciences of the United States of America, 2009
- Ethylene is an endogenous stimulator of cell division in the cambial meristem of PopulusProceedings of the National Academy of Sciences of the United States of America, 2009
- Plant CLE peptides from two distinct functional classes synergistically induce division of vascular cellsProceedings of the National Academy of Sciences of the United States of America, 2008
- Non-cell-autonomous control of vascular stem cell fate by a CLE peptide/receptor systemProceedings of the National Academy of Sciences of the United States of America, 2008
- Mapping methyl jasmonate-mediated transcriptional reprogramming of metabolism and cell cycle progression in cultured Arabidopsis cellsProceedings of the National Academy of Sciences of the United States of America, 2008
- ETHYLENE-INSENSITIVE5 encodes a 5′→3′ exoribonuclease required for regulation of the EIN3-targeting F-box proteins EBF1/2Proceedings of the National Academy of Sciences of the United States of America, 2006
- Different Plant Hormones Regulate Similar Processes through Largely Nonoverlapping Transcriptional ResponsesCell, 2006
- CTR1, a negative regulator of the ethylene response pathway in arabidopsis, encodes a member of the Raf family of protein kinasesCell, 1993