Cloning and Expression Analysis of Aerenchyma Development Related Gene ShRBOH1 in Saussurea inversa Raab-Straube

Abstract

Abstract 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.