The Difference of Physiological and Proteomic Changes in Maize Leaves Adaptation to Drought, Heat, and Combined Both Stresses

Abstract

At the eight-leaf stage, maize is highly sensitive to stresses such as drought, heat, and their combination, which greatly affect its yield. At present, few studies have analyzed maize response to combined drought and heat stress at the eight-leaf stage. In this study, we measured certain physical parameters of maize at the eight-leaf stage when it was exposed to drought, heat, and their combination. The results showed an increase in the content of H2O2 and malondialdehyde (MDA), and in the enzyme activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR), but a decrease in the quantum efficiency of photosystem II (ΦPSII). The most obvious increase or decrease in physical parameters was found under the combined stress condition. Moreover, to identify proteins differentially regulated by the three stress conditions at the eight-leaf stage, total proteins from the maize leaves were identified and quantified using multiplex iTRAQ-based quantitative proteomic and LC-MS/MS methods. In summary, the expression levels of 135, 65, and 201 proteins were significantly changed under the heat, drought and combined stress conditions, respectively. Of the 135, 65, and 201 differentially expressed proteins, 61, 28, and 16 responded exclusively to drought stress, heat stress, and combined stress, respectively. Bioinformatics analysis implied that chaperone proteins and proteases play important roles in the adaptive response of maize to heat stress and combined stress, and that the leaf senescence promoted by ethylene-responsive protein and ripening-related protein may play active roles in maize tolerance to combined drought and heat stress. The signaling pathways related to differentially expressed proteins were obviously different under all three stress conditions. Thus, the functional characterization of these differentially expressed proteins will be helpful for discovering new targets to enhance maize tolerance to stress.

Influence of drought and heat stress, applied independently or in combination during seed development, on qualitative and quantitative aspects of seeds of lentil (Lens culinarisMedikus) genotypes, differing in drought sensitivity

“…Chlorophyll fluorescence, an indicator of efficiency of electron transport during the light reaction of photosynthesis, decreased in the present study due to damage to chlorophyll and possibly proteins of reaction centres, which might impair the electron flow in leaves of stressed lentil plants, in a way similar reports in Kentucky bluegrass ( Poa pratensis L; Jiang & Huang, ), chickpea (Awasthi et al, ), and tomato (Nankishore & Farrell, ). The reduction in photosynthesis, especially in combined stressed plants, might have occurred due to decline in stomatal conductance, decreased leaf water content, damaged chlorophyll, and inhibited carbon fixation enzymes (Zhao et al, ) and is similar to findings in tomato (Nankishore & Farrell, ), chickpea (Awasthi et al, ), and barley (Jedmowski, Ashoub, Momtaz, & Brüggemann, ). The increase in stomatal conductance during heat stress is an adaptive response, which facilitates transpirational cooling of the leaves and is similar to observations in wheat (Sharma, Andersen, Ottosen, & Rosenqvist, ), whereas decrease in stomatal conductance during drought stress may be due to reduced leaf water potential (Ludlow & Muchow, ) or humidity in the atmosphere (Maroco, Pereira, & Chaves, ).…”

Physiology and proteomics of two maize genotypes with different drought resistance

“…In this study, the content of proteases increased in the stressed plants of both the genotypes, which imply a higher rate of damaged/unnecessary protein degradation occurred under stress, indicating the need for sensitive and selective regulation of both protein synthesis and degradation. Similarly, Aranjuelo et al (2011) found an upregulation of one of proteasome subunits in the leaves of alfalfa upon its subjection to a low water supply, and Zhao et al (2016) observed the promotion of protein hydrolysis in maize leaves subjected to drought stress. Carbohydrate and energy metabolism-related proteins like glyceraldehyde-3-phosphate dehydrogenase (GAPDH), malate dehydrogenase 2 and NDPK1 increased in DH, but GAPDH was abundant in LY.…”

Impact of Post-Translational Modifications of Crop Proteins under Abiotic Stress

“…Stable isotope labeling by amino acids in cell culture (SILAC) is one of the in vivo labeling techniques that is applied to plants, and it makes use of metabolic reactions of sample organisms [22,23]. In vitro labeling includes techniques such as an isotope-coded affinity tag (ICAT) and an isobaric tag for relative and absolute quantitation (iTRAQ) [24,25]. The acquisition of mass signals in large-scale proteomic studies employs data-dependent acquisition (DDA) strategies where a fixed number of intact peptides (MS 1 ) are selected as precursors and subsequently analyzed as fragments by tandem mass (MS/MS) [21].…”