Genetic and transformation studies reveal negative regulation of ERS1 ethylene receptor signaling in Arabidopsis
<p>Abstract</p> <p>Background</p> <p>Ethylene receptor single mutants of Arabidopsis do not display a visibly prominent phenotype, but mutants defective in multiple ethylene receptors exhibit a constitutive ethylene response phenotype. It is inferred that ethylene respo...
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BMC
2010-04-01
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Series: | BMC Plant Biology |
Online Access: | http://www.biomedcentral.com/1471-2229/10/60 |
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author | Wen Chi-Kuang Xu Chan Liu Qian |
author_facet | Wen Chi-Kuang Xu Chan Liu Qian |
author_sort | Wen Chi-Kuang |
collection | DOAJ |
description | <p>Abstract</p> <p>Background</p> <p>Ethylene receptor single mutants of Arabidopsis do not display a visibly prominent phenotype, but mutants defective in multiple ethylene receptors exhibit a constitutive ethylene response phenotype. It is inferred that ethylene responses in Arabidopsis are negatively regulated by five functionally redundant ethylene receptors. However, genetic redundancy limits further study of individual receptors and possible receptor interactions. Here, we examined the ethylene response phenotype in two quadruple receptor knockout mutants, (<it>ETR1</it>) <it>ers1 etr2 ein4 ers2 </it>and (<it>ERS1</it>) <it>etr1 etr2 ein4 ers2</it>, to unravel the functions of ETR1 and ERS1. Their functions were also reciprocally inferred from phenotypes of mutants lacking <it>ETR1 </it>or <it>ERS1</it>. Receptor protein levels are correlated with receptor gene expression. Expression levels of the remaining wild-type receptor genes were examined to estimate the receptor amount in each receptor mutant, and to evaluate if effects of <it>ers1 </it>mutations on the ethylene response phenotype were due to receptor functional compensation. As <it>ers1 </it>and <it>ers2 </it>are in the Wassilewskija (Ws) ecotype and <it>etr1</it>, <it>etr2</it>, and <it>ein4 </it>are in the Columbia (Col-0) ecotype, possible effects of ecotype mixture on ethylene responses were also investigated.</p> <p>Results</p> <p>Ethylene responses were scored based on seedling hypocotyl measurement, seedling and rosette growth, and relative <it>Chitinase B </it>(<it>CHIB</it>) expression. Addition of <it>ers1 </it>loss-of-function mutations to any <it>ETR1</it>-containing receptor mutants alleviated ethylene growth inhibition. Growth recovery by <it>ers1 </it>mutation was reversed when the <it>ers1 </it>mutation was complemented by <it>ERS1p:ERS1</it>. The addition of the <it>ers2-3 </it>mutation to receptor mutants did not reverse the growth inhibition. Overexpressing ERS1 receptor protein in (<it>ETR1 ERS1</it>)<it>etr2 ein4 ers2 </it>substantially elevated growth inhibition and <it>CHIB </it>expression. Receptor gene expression analyses did not favor receptor functional compensation upon the loss of <it>ERS1</it>.</p> <p>Conclusions</p> <p>Our results suggest that ERS1 has dual functions in the regulation of ethylene responses. In addition to repressing ethylene responses, ERS1 also promotes ethylene responses in an ETR1-dependent manner. Several lines of evidence support the argument that ecotype mixture does not reverse ethylene responses. Loss of <it>ERS1 </it>did not lead to an increase in total receptor gene expression, and functional compensation was not observed. The inhibitory effects of ERS1 on the ethylene signaling pathway imply negative receptor collaboration.</p> |
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spelling | doaj.art-ee6aab0460f84ebdb848e3db0374273a2022-12-21T20:55:32ZengBMCBMC Plant Biology1471-22292010-04-011016010.1186/1471-2229-10-60Genetic and transformation studies reveal negative regulation of ERS1 ethylene receptor signaling in ArabidopsisWen Chi-KuangXu ChanLiu Qian<p>Abstract</p> <p>Background</p> <p>Ethylene receptor single mutants of Arabidopsis do not display a visibly prominent phenotype, but mutants defective in multiple ethylene receptors exhibit a constitutive ethylene response phenotype. It is inferred that ethylene responses in Arabidopsis are negatively regulated by five functionally redundant ethylene receptors. However, genetic redundancy limits further study of individual receptors and possible receptor interactions. Here, we examined the ethylene response phenotype in two quadruple receptor knockout mutants, (<it>ETR1</it>) <it>ers1 etr2 ein4 ers2 </it>and (<it>ERS1</it>) <it>etr1 etr2 ein4 ers2</it>, to unravel the functions of ETR1 and ERS1. Their functions were also reciprocally inferred from phenotypes of mutants lacking <it>ETR1 </it>or <it>ERS1</it>. Receptor protein levels are correlated with receptor gene expression. Expression levels of the remaining wild-type receptor genes were examined to estimate the receptor amount in each receptor mutant, and to evaluate if effects of <it>ers1 </it>mutations on the ethylene response phenotype were due to receptor functional compensation. As <it>ers1 </it>and <it>ers2 </it>are in the Wassilewskija (Ws) ecotype and <it>etr1</it>, <it>etr2</it>, and <it>ein4 </it>are in the Columbia (Col-0) ecotype, possible effects of ecotype mixture on ethylene responses were also investigated.</p> <p>Results</p> <p>Ethylene responses were scored based on seedling hypocotyl measurement, seedling and rosette growth, and relative <it>Chitinase B </it>(<it>CHIB</it>) expression. Addition of <it>ers1 </it>loss-of-function mutations to any <it>ETR1</it>-containing receptor mutants alleviated ethylene growth inhibition. Growth recovery by <it>ers1 </it>mutation was reversed when the <it>ers1 </it>mutation was complemented by <it>ERS1p:ERS1</it>. The addition of the <it>ers2-3 </it>mutation to receptor mutants did not reverse the growth inhibition. Overexpressing ERS1 receptor protein in (<it>ETR1 ERS1</it>)<it>etr2 ein4 ers2 </it>substantially elevated growth inhibition and <it>CHIB </it>expression. Receptor gene expression analyses did not favor receptor functional compensation upon the loss of <it>ERS1</it>.</p> <p>Conclusions</p> <p>Our results suggest that ERS1 has dual functions in the regulation of ethylene responses. In addition to repressing ethylene responses, ERS1 also promotes ethylene responses in an ETR1-dependent manner. Several lines of evidence support the argument that ecotype mixture does not reverse ethylene responses. Loss of <it>ERS1 </it>did not lead to an increase in total receptor gene expression, and functional compensation was not observed. The inhibitory effects of ERS1 on the ethylene signaling pathway imply negative receptor collaboration.</p>http://www.biomedcentral.com/1471-2229/10/60 |
spellingShingle | Wen Chi-Kuang Xu Chan Liu Qian Genetic and transformation studies reveal negative regulation of ERS1 ethylene receptor signaling in Arabidopsis BMC Plant Biology |
title | Genetic and transformation studies reveal negative regulation of ERS1 ethylene receptor signaling in Arabidopsis |
title_full | Genetic and transformation studies reveal negative regulation of ERS1 ethylene receptor signaling in Arabidopsis |
title_fullStr | Genetic and transformation studies reveal negative regulation of ERS1 ethylene receptor signaling in Arabidopsis |
title_full_unstemmed | Genetic and transformation studies reveal negative regulation of ERS1 ethylene receptor signaling in Arabidopsis |
title_short | Genetic and transformation studies reveal negative regulation of ERS1 ethylene receptor signaling in Arabidopsis |
title_sort | genetic and transformation studies reveal negative regulation of ers1 ethylene receptor signaling in arabidopsis |
url | http://www.biomedcentral.com/1471-2229/10/60 |
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