Physiological and Differential Proteomic Analyses of Imitation Drought Stress Response in Sorghum bicolor Root at the Seedling Stage

Abstract

Drought is one of the most important constraints on the growth and productivity of many crops, including sorghum. However, as a primary sensing organ, the plant root response to drought has not been well documented at the proteomic level. In the present study, we compared physiological alteration and differential accumulation of proteins in the roots of sorghum (Sorghum bicolor) inbred line BT×623 response to Polyethylene Glycol (PEG)-induced drought stress at the seedling stage. Drought stress (up to 24 h after PEG treatment) resulted in increased accumulation of reactive oxygen species (ROS) and subsequent lipid peroxidation. The proline content was increased in drought-stressed plants. The physiological mechanism of sorghum root response to drought was attributed to the elimination of harmful free radicals and to the alleviation of oxidative stress via the synergistic action of antioxidant enzymes, such as superoxide dismutase, peroxidase, and polyphenol oxidase. The high-resolution proteome map demonstrated significant variations in about 65 protein spots detected on Coomassie Brilliant Blue-stained 2-DE gels. Of these, 52 protein spots were identified by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF-TOF MS) representing 49 unique proteins; the levels of 43 protein spots were increased, and 22 were decreased under drought condition. The proteins identified in this study are involved in a variety of cellular functions, including carbohydrate and energy metabolism, antioxidant and defense response, protein synthesis/processing/degradation, transcriptional regulation, amino acid biosynthesis, and nitrogen metabolism, which contribute jointly to the molecular mechanism of outstanding drought tolerance in sorghum plants. Analysis of protein expression patterns and physiological analysis revealed that proteins associated with changes in energy usage; osmotic adjustment; ROS scavenging; and protein synthesis, processing, and proteolysis play important roles in maintaining root growth under drought stress. This study provides new insight for better understanding of the molecular basis of drought stress responses, aiming to improve plant drought tolerance for enhanced yield.

Sorghum’s Whole-Plant Transcriptome and Proteome Responses to Drought Stress: A Review

“…In this section, we summarize proteomic studies of sorghum plants under drought stress. Compared to the sorghum whole-plant transcriptomic analyses discussed above, the complementary proteomic work of this crop is extremely limited to a few publications [ 71 , 115 , 116 , 117 ] ( Table 3 ). This highlights the need for more studies to analyze the dynamics of sorghum proteomes in response to water deprivation as we seek to understand the molecular networks that contribute to the crop’s natural resilience to drought.…”

“…Another recent study [ 116 ] also analyzed the root proteome changes of the Bx623 sorghum inbred line in response to a 24 h treatment in 10% PEG-induced osmotic stress using 2D gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF-TOF MS) analysis. The study reported 105 differentially accumulated proteins in response to the PEG treatment, with 65 of these with a 2-fold change in abundance.…”

“…In summary, sorghum molecular responses to water deprivation involve stress perception/signaling events followed by gene, protein, and metabolite expression changes. The reviewed transcriptomics [ 19 , 73 , 74 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 ] and proteomics [ 71 , 115 , 116 , 117 ] studies also affirm such complexities in drought tolerance mechanisms of the crop. However, because the studies employed a wide range of experimental designs, detailed comparisons between individual drought-responsive genes and proteins are difficult to perform across experiments.…”

An efficient protein extraction method applied to mangrove plant Kandelia obovata leaves for proteomic analysis

“…Proteomics has been developed as an important approach for studying plant functional genomics [ 1 ], which can be used to detect the post-transcriptional modification [ 2 ]. Two-dimensional gel electrophoresis (2-DE) was an efficient and powerful strategy to study complex gene expression at the protein level [ 3 – 5 ]. The quality of protein sample was the most crucial steps for optimal results in proteomic analysis.…”

Changes in the Flower and Leaf Proteome of Common Buckwheat (Fagopyrum esculentum Moench) under High Temperature

“…To study the proteome we used two-dimensional electrophoresis in combination with liquid chromatography-mass spectrometry (nanoLC-MS/MS) and peptide mass fingerprinting (PMF). Although there have been advances in the methodology of proteome research in recent years, the methods used in our study are still adequate and widely used in studies similar to ours [ 22 , 23 , 24 , 25 ]. We identified proteins showing differences in abundance in response to heat in the two buckwheat accessions.…”