مستخلص: |
Class III peroxidases (PRX) are a family of plant-specific peroxidases that play an important role in plant growth and development as well as in abiotic stresses. Foxtail millet (Setaria italica L.), as a C4 plant, is a model plant for stress resistance. However, the function of class III peroxidases family genes is rarely reported in foxtail millet. A genome-wide expression analysis was conducted to investigate the expression pattern of class III peroxidase gene family (SitPRXs) under drought stress and ABA induction. In this study, 132 members of the Class III PRX gene family were identified in the whole genome in foxtail millet by bioinformatics and named SitPRX1-SitPRX132 according to their chromosomal position. 132 members were classified into Mα, Mβ, Mγ, MIKCC, and MIKC* subfamilies by phylogenetic analysis of foxtail millet, Arabidopsis, and rice. Gene structure and conserved motif analysis indicated a high level of conservation in the same subfamily. Gene duplication analysis revealed fragmental duplication in 17 SitPRX genes (13%) and tandem duplication in 78 SitPRX genes (59%), thus tandem duplication events playing an important role in SitPRX gene amplification. Interspecies homology analysis with Arabidopsis, rice and maize revealed that most SitPRXs were formed after dicotyledonous and monocotyledonous plants diverged. Transcriptome analysis implied that members of the SitPRX gene family were differentially expressed in seedlings, roots, stems, and leaves, as well as in panicles in foxtail millet. Analysis of promoter cis-acting elements showed that 79 SitPRXs contained cis-acting elements associated with drought stress response, and further qRT-PCR analysis showed that SitPRX12, SitPRX41, SitPRX81, SitPRX110, and SitPRX126 were induced to be expressed by PEG and ABA, suggesting that these genes may be regulated through an ABA-dependent signalling pathway in response to drought stress and could be used as these genes may be candidates for further studies on the drought resistance function of the class III PRX gene family. These results of this study provide new information for the comprehensive analysis of the structure and biological functions of SitPRX genes, the molecular mechanism of drought resistance, and molecular breeding in foxtail millet, with a view of providing ideas for the breeding of new varieties of highly efficient stress-resistant crops in the future. [ABSTRACT FROM AUTHOR] |