Unraveling the Root Proteome Changes and Its Relationship to Molecular Mechanism Underlying Salt Stress Response in Radish (Raphanus sativus L.)

Abstract

To understand the molecular mechanism underlying salt stress response in radish, iTRAQ-based proteomic analysis was conducted to investigate the differences in protein species abundance under different salt treatments. In total, 851, 706, and 685 differential abundance protein species (DAPS) were identified between CK vs. Na100, CK vs. Na200, and Na100 vs. Na200, respectively. Functional annotation analysis revealed that salt stress elicited complex proteomic alterations in radish roots involved in carbohydrate and energy metabolism, protein metabolism, signal transduction, transcription regulation, stress and defense and transport. Additionally, the expression levels of nine genes encoding DAPS were further verified using RT-qPCR. The integrative analysis of transcriptomic and proteomic data in conjunction with miRNAs was further performed to strengthen the understanding of radish response to salinity. The genes responsible for signal transduction, ROS scavenging and transport activities as well as several key miRNAs including miR171, miR395, and miR398 played crucial roles in salt stress response in radish. Based on these findings, a schematic genetic regulatory network of salt stress response was proposed. This study provided valuable insights into the molecular mechanism underlying salt stress response in radish roots and would facilitate developing effective strategies toward genetically engineered salt-tolerant radish and other root vegetable crops.

Comparative proteomic analysis provides insight into a complex regulatory network of taproot formation in radish (Raphanus sativus L.)

“…The relatively weak correlation of genes at mRNA and protein level indicates that an alteration in a proportion of transcripts may not be translated into changes in protein abundance. Low congruency of genes in mRNA and protein level was similar with other previous studies 20 , 35 .…”

iTRAQ-based quantitative proteomic analysis of dark-germinated soybeans in response to salt stress

“…NaCl stress signicantly enhanced the accumulation of POD (Q9XFI8) while decreasing the POD (C6TBQ4) abundance, suggesting that different POD members may have different functions in salt stress responses in soybeans, which has also been reported in radishes under salt stress. 40 In addition, from the present iTRAQ data, some defenserelated DAPs were also induced under salt stress conditions, such as stress responsive alpha-beta barrel domain-containing protein (C6T5C9), low-temperature-induced 65 kDa protein (K7LDT9), heat shock 70 kDa protein (P26413) and stressinduced protein SAM22 (P26987). Cellular dehydration can be caused by the decreased water potential of a salt solution.…”

“…These results potentially implied that dark germinated soybeans cope with salt stress by promoting protein synthesis and suppressing protein degradation to maintain the protein metabolic balance, which was similar to the results of a previous study. 45 Beyond that, two of the four eukaryotic translation initiation factors, associated with protein biosynthesis pathways, were induced by salt treatment. Metabolism represents the basic physiological processes that maintain cell living.…”

Peer Review #1 of "The photo-inhibition of camphor leaves (Cinnamomum camphora L.) by NaCl stress based on physiological, chloroplast structure and comparative proteomic analysis (v0.1)"

“…Malate dehydrogenase family proteins participate in the TCA cycle, which is the second step of respiration. A 100 mM NaCl treatment caused a 0.47-fold increased expression of malate dehydrogenase proteins in radish (Raphanus sativus L.) (Sun et al, 2017). Mitogen-activated protein kinase 4 (MKK4), a member of the MAP kinase family, is expressed in response to cellular stress (Cuenda, 2000).…”

“…Isobaric tags for relative and absolute quantitation (iTRAQ) analysis has been used for elucidating various mechanisms of responses to salt stress radish (Raphanus sativus L.) (Sun et al, 2017), Paulownia fortunei (Deng et al, 2017), tomato (Lycopersicon esculentum) and apple (Malus domestica) (Hu et al, 2016). The current study attempts to investigate the influence of 103.45 mM NaCl, which is the average salinity of Jiangsu coastal lands, on camphor seedling by the iTRAQ method combined with physiological analyses.…”