Classical ethylene insensitive mutants of the Arabidopsis EIN2 orthologue lack the expected 'hypernodulation' response in Lotus japonicus

Chan, Pick Kuen, Biswas, Bandana and Gresshoff, Peter M. (2013) Classical ethylene insensitive mutants of the Arabidopsis EIN2 orthologue lack the expected 'hypernodulation' response in Lotus japonicus. Journal of Integrative Plant Biology, 55 4: 395-408. doi:10.1111/jipb.12040


Author Chan, Pick Kuen
Biswas, Bandana
Gresshoff, Peter M.
Title Classical ethylene insensitive mutants of the Arabidopsis EIN2 orthologue lack the expected 'hypernodulation' response in Lotus japonicus
Formatted title
Classical ethylene insensitive mutants of the Arabidopsis EIN2 orthologue lack the expected 'hypernodulation' response in Lotus japonicus
Journal name Journal of Integrative Plant Biology   Check publisher's open access policy
ISSN 1672-9072
1744-7909
Publication date 2013-04
Sub-type Article (original research)
DOI 10.1111/jipb.12040
Open Access Status
Volume 55
Issue 4
Start page 395
End page 408
Total pages 14
Place of publication United Kingdom
Publisher Wiley-Blackwell Publishing
Collection year 2014
Language eng
Formatted abstract
Three independent ethylene insensitive mutants were selected from an EMS- mutagenized population of Lotus japonicus MG-20 (Miyakojima). The mutants, called ‘Enigma’, were mutated in the LjEIN2a gene from Lotus chromosome 1, sharing significant homology with Arabidopsis EIN2 (ethylene-insensitive2). All three alleles showed classical ethylene insensitivity phenotypes (e.g., Triple Response), but lacked the increased nodulation phenotype commonly associated with ethylene insensitivity. Indeed, all showed a marginal reduction in nodule number per plant, a phenotype that is enigmatic to sickle, an ethylene-insensitive EIN2 mutant in Medicago truncatula. In contrast to wild type, but similar to an ETR1-1 ethylene ethylene-insensitive transgenic of L. japonicus, enigma mutants formed nodules in between the protoxylem poles, demonstrating the influence of ethylene on radial positioning. Suppression of nodule numbers by nitrate and colonisation by mycorrhizal fungi in the enigma-1 mutant were indistinguishable from the wild-type MG-20. However, reflecting endogenous ethylene feedback, the enigma-1 mutant released more than twice the wild-type amount of ethylene. enigma-1 had a moderate reduction in growth, greater root mass (and lateral root formation), delayed flowering and ripening, smaller pods and seeds. Expression analysis of ethylene-regulated genes, such as ETR1, NRL1 (neverripe-like 1), and EIL3 in shoots and roots of enigma-1 and MG-20 illustrated that the ethylene-insensitive mutation strongly affected transcriptional responses in the root. These mutants open the possibility that EIN2 in L. japonicus, a determinate nodulating legume, acts in a more complex fashion possibly through the presence of a duplicated copy of LjEIN2.
Keyword ABA
Development
Ethylene
Legume
Nodulation
Symbiosis
Pisum-sativum-L
Signal-transduction pathway
L. cv Sparkle
Medicago-truncatula
Nodule development
Abscisic-acid
Soybean roots
Glycine-max
1-aminocyclopropane-1-carboxylic acid
Symbiotic phenotype
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Centre for Integrative Legume Research Publications
School of Agriculture and Food Sciences
Official 2014 Collection
 
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Citation counts: TR Web of Science Citation Count  Cited 9 times in Thomson Reuters Web of Science Article | Citations
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