Background: Wheat (Triticum aestivum L.) is a staple crop in the world, but is only moderately salt tolerant. However, salt stress affects one-fth of irrigated agricultural land in the world, it is of great importance to cultivate salt-tolerant varieties to improve the global wheat production.Results: In this study, over 90,000 wheat seeds of cultivar 'Luyuan502' were mutated by EMS, and 2000 salt-tolerant lines were harvested from salinized eld. By analysis of ethylene sensitivity, salt related physiological factors, and preliminary crop yield, 12 salt-tolerant wheat lines with high production were selected among the crop plants. Transcriptome analysis indicated that a large number of the transcripts levels were signi cantly altered, mainly based on antenna proteins involved in photosynthesis, biosynthesis of secondary metabolites, cyanoamino acid metabolism, carotenoid biosynthesis, thiamine metabolism, and cutin, suberine and wax biosynthesis pathways including CABs, PERs/PODs, BGLUs, CYP707s, and ZEPs. qRT-PCR analysis revealed that the expressions of salt-related genes in the wheat lines were mostly higher than the wild type, and salt stress can signi cantly increase the expression levels of the ethylene-related genes in the wheat lines. Based on transcriptomic data, nine novel wheat ERFs were identi ed and analyzed, and it is suggested that they may play important roles in mediation of ethylene response and salt tolerance.Conclusion: Salt-tolerant wheat mutant lines with ethylene insensitivity were obtained from screen of a wheat EMS-mutagenized pool. Transcriptome data showed that the mutant plants exhibit signi cant alterations in the antenna proteins involved in various biological processes. Expression analysis suggests that ERFs may mediate ethylene response and salt tolerance of the wheat lines.

The ETR1 receptor plays a predominant role in ethylene signaling in Arabidopsis thaliana. Previous studies showed that both RTE1 and CPR5 can directly bind to the ETR1 receptor and regulate ethylene signaling. RTE1 was suggested to promote the ETR1 receptor signaling by in uencing its conformation, but little is known about the regulatory mechanism of CPR5 in ethylene signaling. In this study, we presented data showing that both RTE1 and CPR5 bound to the N-terminal domains of ETR1, and regulated ethylene signaling via the ethylene receptor. On the other hand, the research provided evidence indicating that CPR5 could act as a nucleoporin to regulate the ethylene-related mRNAs export out of the nucleus, while RTE1 or its homolog (RTH) had no effect on the nucleocytoplasmic transport of mRNAs.Nuclear qRT-PCR analysis and poly(A)-mRNA in situ hybridization showed that defect of CPR5 restricted nucleocytoplasmic transport of mRNAs. These results advance our understanding of the regulatory mechanism of CPR5 in ethylene signaling. Key MessageArabidopsis CPR5 is involved in regulation of ethylene signaling via two different ways: interacting with the ETR1 N-terminal domains, and controlling nucleocytoplasmic transport of ethylene-related mRNAs.

The ETR1 receptor plays a predominant role in ethylene signaling in Arabidopsis thaliana. Previous studies showed that both RTE1 and CPR5 can directly bind to the ETR1 receptor and regulate ethylene signaling. RTE1 was suggested to promote the ETR1 receptor signaling by influencing its conformation, but little is known about the regulatory mechanism of CPR5 in ethylene signaling. In this study, we presented data showing that both RTE1 and CPR5 bound to the N-terminal domains of ETR1, and regulated ethylene signaling via the ethylene receptor. On the other hand, the research provided evidence indicating that CPR5 could act as a nucleoporin to regulate the ethylene-related mRNAs export out of the nucleus, while RTE1 or its homolog (RTH) had no effect on the nucleocytoplasmic transport of mRNAs. Nuclear qRT-PCR analysis and poly(A)-mRNA in situ hybridization showed that defect of CPR5 restricted nucleocytoplasmic transport of mRNAs. These results advance our understanding of the regulatory mechanism of CPR5 in ethylene signaling.

Background: Wheat (Triticum aestivum L.) is a staple crop in the world, but is only moderately salt tolerant. However, salt stress affects one-fifth of irrigated agricultural land in the world, it is of great importance to cultivate salt-tolerant varieties to improve the global wheat production. Results: In this study, over 90,000 wheat seeds of cultivar ‘Luyuan502’ were mutated by EMS, and 2000 salt-tolerant lines were harvested from salinized field. By analysis of ethylene sensitivity, salt related physiological factors, and preliminary crop yield, 12 salt-tolerant wheat lines with high production were selected among the crop plants. Transcriptome analysis indicated that a large number of the transcripts levels were significantly altered, mainly based on antenna proteins involved in photosynthesis, biosynthesis of secondary metabolites, cyanoamino acid metabolism, carotenoid biosynthesis, thiamine metabolism, and cutin, suberine and wax biosynthesis pathways including CABs, PERs/PODs, BGLUs, CYP707s, and ZEPs. qRT-PCR analysis revealed that the expressions of salt-related genes in the wheat lines were mostly higher than the wild type, and salt stress can significantly increase the expression levels of the ethylene-related genes in the wheat lines. Based on transcriptomic data, nine novel wheat ERFs were identified and analyzed, and it is suggested that they may play important roles in mediation of ethylene response and salt tolerance.Conclusion: Salt-tolerant wheat mutant lines with ethylene insensitivity were obtained from screen of a wheat EMS-mutagenized pool. Transcriptome data showed that the mutant plants exhibit significant alterations in the antenna proteins involved in various biological processes. Expression analysis suggests that ERFs may mediate ethylene response and salt tolerance of the wheat lines.

Key message:This study reveals that CPR5 is involved in the regulation of ethylene 15 signaling via two different ways: interacting with the N-terminal domains of ERT1 16 and controlling the nucleocytoplasmic transport of mRNAs in ethylene signaling 17 pathway. 18 19 2 Abstract ETR1 is the major ethylene receptor in Arabidopsis thaliana. Previous 20 studies showed that RTE1 and CPR5 can bind to ETR1 and play regulatory roles in 21 ethylene signaling. RTE1 has been suggested to promote ETR1 signal transduction by 22 influencing the conformation of ETR1, but little is known about the mechanism of 23 CPR5 on the regulation of ETR1 signaling. In this study, we showed that both CPR5 24 and RTE1 could interact with the N-terminal transmembrane domains of ETR1, and 25 CPR5 needs at least three transmembrane domains of ETR1 while RTE1 needs only 26 two for the binding. As CPR5 has also been shown to be localized in the nuclear 27 membrane and might act as a nucleoporin, we analyzed the effects of CPR5 on the 28 nucleocytoplasmic transport of ethylene-related mRNAs using poly(A)-mRNA in situ 29 hybridization and real-time quantitative PCR (qPCR), and the results indicated that 30 CPR5 could selectively regulate the nucleocytoplasmic transport of mRNAs in 31 ethylene signaling pathway. In contrast, the nucleoporin mutants (nup160, nup96-1 32 and nup96-2) dramatically accumulated all the examined mRNAs in the nucleus. In 33 conclusion, the present study provides evidence demonstrating that CPR5 regulates 34 ethylene signaling through interacting with the ETR1 receptor and controlling the 35 mRNAs nucleocytoplasmic transport in ethylene signaling pathway. 36 37