Comparative Proteomic and Physiological Analyses of Two Divergent Maize Inbred Lines Provide More Insights into Drought-Stress Tolerance Mechanisms

Abstract

Drought stress is the major abiotic factor threatening maize (Zea mays L.) yield globally. Therefore, revealing the molecular mechanisms fundamental to drought tolerance in maize becomes imperative. Herein, we conducted a comprehensive comparative analysis of two maize inbred lines contrasting in drought stress tolerance based on their physiological and proteomic responses at the seedling stage. Our observations showed that divergent stress tolerance mechanisms exist between the two inbred-lines at physiological and proteomic levels, with YE8112 being comparatively more tolerant than MO17 owing to its maintenance of higher relative leaf water and proline contents, greater increase in peroxidase (POD) activity, along with decreased level of lipid peroxidation under stressed conditions. Using an iTRAQ (isobaric tags for relative and absolute quantification)-based method, we identified a total of 721 differentially abundant proteins (DAPs). Amongst these, we fished out five essential sets of drought responsive DAPs, including 13 DAPs specific to YE8112, 107 specific DAPs shared between drought-sensitive and drought-tolerant lines after drought treatment (SD_TD), three DAPs of YE8112 also regulated in SD_TD, 84 DAPs unique to MO17, and five overlapping DAPs between the two inbred lines. The most significantly enriched DAPs in YE8112 were associated with the photosynthesis antenna proteins pathway, whilst those in MO17 were related to C5-branched dibasic acid metabolism and RNA transport pathways. The changes in protein abundance were consistent with the observed physiological characterizations of the two inbred lines. Further, quantitative real-time polymerase chain reaction (qRT-PCR) analysis results confirmed the iTRAQ sequencing data. The higher drought tolerance of YE8112 was attributed to: activation of photosynthesis proteins involved in balancing light capture and utilization; enhanced lipid-metabolism; development of abiotic and biotic cross-tolerance mechanisms; increased cellular detoxification capacity; activation of chaperones that stabilize other proteins against drought-induced denaturation; and reduced synthesis of redundant proteins to help save energy to battle drought stress. These findings provide further insights into the molecular signatures underpinning maize drought stress tolerance.

Physiological and proteomic responses to drought stress in leaves of Amygdalus Mira (Koehne) Yü et Lu

“…Two mechanism including to drought avoidance and drought tolerance were used to adapt to drought stress (Kooyers 2015). By drought avoidance, plants often reduce growth to save energy cost and reduce water losses (Zenda et al, 2018). Compared to controls seedlings, growth of A. Mira seedlings was inhibited after drought treatment, demonstrating the suppression of drought on growth of A.…”

DIA (Data Independent Acquisition) proteomic based study on maize filling-kernel stage drought stress-responsive proteins and metabolic pathways

“…Moreover, the ubiquitin-dependent proteolytic pathway degrades most proteins and is the major proteolytic mechanism in eukaryotic cells [55]. Thus, here, the up-regulation of SCE1 implies that cells promote the proteins and enzymes involved in protein ubiquitination in order to protect themselves under drought stress [35].…”

“…Earlier, we employed the isobaric tags for absolute quantification (iTRAQ) strategy to perform proteomics analysis and identify key proteins and metabolic pathways regulating the drought stress response in maize [35][36][37][38]. We observed diverse key drought responsive proteins, including chlorophyll a-b binding proteins (Lhcb5-1 and 542320/Lhcb5-2) associated with the light-harvesting complex; lipid metabolism related non-specific lipid transfer proteins [35]; histone H2A proteins (Zm00001d006547, 100216750), carbohydrate metabolism-related protein malate dehydrogenase (MDH; Zm00001d009640) and several peroxidases [36]; histone deacetylase (HDAC), HSPs, MDH, GSTs, seed storage proteins 50kD c-zein, Z1D alpha zein [37]; peroxidase (Zm00001d008898), stress responsive protein (100283176) and oxidoreductase family proteins [38]. Notably, these genes and proteins were mainly involved in photosynthesis antenna proteins, nitrogen metabolism, secondary metabolism related pathways, especially in the tolerant maize genotype ND476 under drought stress [28,35,38].…”

Adapting Cereal Grain Crops to Drought Stress: 2020 and Beyond

“…Photosynthesis (antenna protein) pathway related genes lhcb5-1 and lhcb5-2 are part of the light harvesting complexes (LHCs) and the electron transport components of the PSII of the plant photosynthesis machinery, where they participate as peripheral antenna systems enabling more efficient absorption of light energy [125,126]. Further, Lhch5-1 is involved in the intracellular non-photochemical quenching and the cysteine biosynthesis processes [91]. Previously, the photosynthesis pathway has been significantly enriched in drought stress response in maize, with chlorophyll a-b binding proteins being up-regulated in an ABA-dependent manner [87,91], and pearl millet [127].…”

“…Further, Lhch5-1 is involved in the intracellular non-photochemical quenching and the cysteine biosynthesis processes [91]. Previously, the photosynthesis pathway has been significantly enriched in drought stress response in maize, with chlorophyll a-b binding proteins being up-regulated in an ABA-dependent manner [87,91], and pearl millet [127]. This photosynthesis related pathway plays a critical role in balancing light capture and utilization to avoid photoinhibition of the PSII [87].…”