Saussurea inversa is a perennial herb used in traditional Chinese medicine and is effective against rheumatoid arthritis. In this study, we sequenced the complete mitochondrial (mt) genome of S. inversa (GenBank accession number: ON584565.1). The circular mt genome of S. inversa was 335,372 bp in length, containing 62 genes, including 33 mRNAs, 22 tRNAs, 6 rRNAs, and 1 pseudogene, along with 1626 open reading frames. The GC content was 45.14%. Predictive analysis revealed substantial RNA editing, with ccmFn being the most abundantly edited gene, showing 36 sites. Gene migration between the mt and chloroplast (cp) genomes of S. inversa was observed through the detection of homologous gene fragments. Phylogenetic analysis revealed that S. inversa was clustered with Arctium tomentosum (Asteraceae). Our findings provide extensive information regarding the mt genome of S. inversa and help lay the foundation for future studies on its genetic variations, phylogeny, and breeding via the analysis of the mt genome.

Saussurea inversa is a perennial herb used in traditional Chinese medicine and is effective against rheumatoid arthritis. In this study, we sequenced the complete mitochondrial(mt) genome of S. inversa (GenBank accession number: ON584565.1). The circular mt genome of S. inversa was 335,372 bp in length, containing 62 genes, including 33 mRNAs, 22 tRNAs, six rRNAs, and one pseudo-gene, with 1,626 open reading frames. The GC content was 45.14%. Predictive analysis of substantial RNA-editing of its presence found that the most abundant RNA editing is ccmFn, with 36. Gene migration was observed to occur between the mt and chloroplast(cp) genomes of S. inversa via the detection of homologous gene fragments. Phylogenetic analysis revealed that S. inversa was clustered with Arctium tomentosum (Asteraceae). Our findings provide extensive information regarding the mt genome of S. inversa and help lay the foundation for future studies on the genetic variations, phylogeny, and breeding of S. inversa via an analysis of the mt genome.

Saussurea inversa Raab-Straube is a typical alpine plant with well-developed aerenchyma as its most representative structural feature. It has important theoretical significance for investigating the adaptive mechanisms of alpine plants to the environment through studying the formation and development of aerenchyma in S. inversa. In this study, the aerenchyma development-related gene ShRBOH1 (GenBank accession number OP727799) was cloned from S. inversa by RT-PCR with RACE technology. Sequence analysis showed that the cDNA of ShRBOH1 was 2,158 bp in length, which contained an open reading frame of 2,031 bp encoding 676 amino acids. Subcellular localization prediction showed that the ShRBOH1 protein was located in the cytoplasmic membrane, which was consistent with the localization of the NADPH protein. Comparison of homology amino acid sequence indicated that ShRBOH1 had higher similarity with CcRBOH1 of Cynara cardunculus L.. The qRT-PCR analysis showed that the ShRBOH1 gene was expressed in roots, stems and leaves, and the expression level in stems was significantly lower than in other tissues; the expression of the ShRBOH1 gene was down-regulated under UV stress, up-regulated under cold stress, and first up-regulated, then down-regulated and finally up-regulated under hypoxia stress. By comparing the changes in reactive oxygen species (ROS) content under the three kinds of stresses, the results showed that the changes were significant only under hypoxic stress and were positively correlated with the expression of ShRBOH1. It is hypothesized that ShRBOH1 positively regulates the formation of aerenchyma by ROS mediation, suggesting that the aerenchyma is mainly an important structure for adapting to hypoxia stress in alpine environments.