Abstract
BackgroundDrought is one of the most adverse environmental factors limiting crop productions and it is important to identify key genetic determinants for food safety. Calcium-dependent protein kinases (CPKs) are known to be involved in plant growth, development, and environmental stresses. However, biological functions and regulatory mechanisms of many plant CPKs have not been explored. In our previous study, abundance of the wheat CPK34 (TaCPK34) protein was remarkably upregulated in wheat plants suffering from drought stress, inferring that it could be involved in this stress. Therefore, here we further detected its function and mechanism in response to drought stress.ResultsTranscripts of the TaCPK34 gene were significantly induced after PEG-stimulated water deficiency (20% PEG6000) or 100 μM abscisic acid (ABA) treatments. The TaCPK34 gene was transiently silenced in wheat genome by using barley stripe mosaic virus-induced silencing (BSMV-VIGS) method. After 14 days of drought stress, the transiently TaCPK34-silenced wheat seedlings showed more sensitivity compared with control, and the plant biomasses and relative water contents significantly decreased, whereas soluble sugar and MDA contents increased. The iTRAQ-based quantitative proteomics was employed to measure the protein expression profiles in leaves of the transiently TaCPK34-silenced wheat plants after drought stress. There were 6103 proteins identified, of these, 51 proteins exhibited significantly altered abundance, they were involved in diverse function. And sequence analysis on the promoters of genes, which encoded the above identified proteins, indicated that some promoters harbored some ABA-responsive elements. We determined the interactions between TaCPK34 and three identified proteins by using bimolecular fluorescent complementation (BiFC) method and our data indicated that TaCPK34directly interacted with the glutathione S-transferase 1 and prx113, respectively.ConclusionsOur study suggested that the TaCPK34 gene played positive roles in wheat response to drought stress through directly or indirectly regulating the expression of ABA-dependent manner genes, which were encoding identified proteins from iTRAQ-based quantitative proteomics. And it could be used as one potential gene to develop crop cultivars with improved drought tolerance.
Highlights
Drought is one of the most adverse environmental factors limiting crop productions and it is important to identify key genetic determinants for food safety
One protein that matched to TuCPK34
EMS58754) were identified from Triticum urartu, and its sequence of amino acid alignment showed 87% similarity to Chinese Spring (CS) (Figure S1), suggesting that the wheat CPK34 (TaCPK34) was the homologue of TuCPK34 in Triticum aestivum (Figure S1)
Summary
Drought is one of the most adverse environmental factors limiting crop productions and it is important to identify key genetic determinants for food safety. Calcium-dependent protein kinases (CPKs) are known to be involved in plant growth, development, and environmental stresses. Cold, heat, and salt are major adverse environmental stresses that greatly limit crop yields and quality. It is pivotal to understand the molecular mechanisms underlying stress responses,identify important genetic genes and develop crop cultivars with enhanced stress tolerance. Plants respond to environmental stresses by regulating the expression of numerous stress-responsive genes through complicated signaling pathways. Several classes of Ca2+ sensors: calcium-dependent protein kinases (CPKs or CDPKs), calmodulins (CaMs) and CaM-like proteins and calcineurin B-like proteins (CBLs) have been reported to involve in the perception and transmission of intracellular Ca2+ concentrations [3]. CaMs and CBLs do not have enzymatic activities and do not directly transmit the Ca2+ signals, whereas CPKs can sense Ca2+ signals and directly mediate a variety of cellular responses [4]
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