iTRAQ-Based Comparative Proteomic Analysis Provides Insights into Molecular Mechanisms of Salt Tolerance in Sugar Beet (Beta vulgaris L.)

Abstract

Salinity is one of the major abiotic stress factors that limit plant growth and crop yield worldwide. To understand the molecular mechanisms and screen the key proteins in response of sugar beet (Beta vulgaris L.) to salt, in the present study, the proteomics of roots and shoots in three-week-old sugar beet plants exposed to 50 mM NaCl for 72 h was investigated by isobaric Tags for Relative and Absolute Quantitation (iTRAQ) technology. The results showed that 105 and 30 differentially expressed proteins (DEPs) were identified in roots and shoots of salt-treated plants compared with untreated plants, respectively. There were 46 proteins up-regulated and 59 proteins down-regulated in roots; and 13 up-regulated proteins and 17 down-regulated proteins found in shoots, respectively. These DEPs were mainly involved in carbohydrate metabolism, energy metabolism, lipid metabolism, biosynthesis of secondary metabolites, transcription, translation, protein folding, sorting, and degradation as well as transport. It is worth emphasizing that some novel salt-responsive proteins were identified, such as PFK5, MDH, KAT2, ACAD10, CYP51, F3H, TAL, SRPR, ZOG, V-H+-ATPase, V-H+-PPase, PIPs, TIPs, and tubulin α-2/β-1 chain. qRT-PCR analysis showed that six of the selected proteins, including BvPIP1-4, BvVP and BvVAP in root and BvTAL, BvURO-D1, and BvZOG in shoot, displayed good correlation between the expression levels of protein and mRNA. These novel proteins provide a good starting point for further research into their functions using genetic or other approaches. These findings should significantly improve the understanding of the molecular mechanisms involved in salt tolerance of sugar beet plants.

iTRAQ protein profile analysis of sugar beet under salt stress: different coping mechanisms in leaves and roots

“…In Yu et al [12] the changes were only induced by short-term salt stress (30 min and 1 h) and examined only proteome/phosphoproteome changes in M14 leaves. Finally, Wu et al studied proteome changes in seedlings, but only in shoots and roots, and after a very long exposure (50 mm NaCl for 72 h) [13]. While these studies are useful, we note that plant proteome responses to salt stress depend on its intensity, duration and the organ examined [14,15].…”

Sugar Beet (Beta vulgaris) Guard Cells Responses to Salinity Stress: A Proteomic Analysis

“…Among environmental factors, salinity can have a serious impact on plant yield. With the reported rate of soil salinization 3 ha/min [1], salinity becomes a major challenge worldwide [2]. Moreover, the current trends in population dynamics, urbanization, and climate change will exacerbate the process of land salinization.…”

“…Therefore, this plant could be a good resource to explore salt tolerance mechanisms and to identify proteins and genes involved in salt tolerance [13]. Currently, proteomic studies on salt tolerance in sugar beet have been limited to tissues such as shoot, root, and leaf [2,14,15], with no studies on GCs reported to date. In this study, the GCs isolated for proteomic analysis were validated with microscopic observation, viability tests and comparing guard cell-specific proteins in mesophyll and guard cell samples.…”

iTRAQ protein profile analysis of leaves and roots of sugar beet (Beta vulgaris) differing in response to salt stress

“…Yu et al analyzed the changes in proteome and phosphoproteome of M14 leaves induced by short-term salt stress (30min and 1 hour) [12] . Wu et al studied changes in the proteome of beet seedlings treated with 50mm NaCl for 72h and 30 and 105 differentially expressed proteins were identified in the shoots and roots, respectively [13] . However, how plants respond to salinity depends on the organ, intensity and duration of the stress, which may lead to various changes at the proteome level [14,15] .…”