Comparison of the Drought Stress Responses of Tolerant and Sensitive Wheat Cultivars during Grain Filling: Impact of Invertase Activity on Carbon Metabolism during Kernel Development

Water-deficit stresses such as drought and salinity are the most important factors limiting crop productivity. Hence, understanding the plant responses to these stresses is key for the improvement of their tolerance and yield. In this study M. truncatula plants were subjected to 250 mM NaCl as well as reduced irrigation (No-W) and 250 g/L polyethylene glycol (PEG)-6000 to induce salinity and drought stress, respectively, provoking a drop to −1.7 MPa in leaf water potential. The whole plant physiology and metabolism was explored by characterizing the stress responses at root, phloem sap and leaf organ level. PEG treatment led to some typical responses of plants to drought stress, but in addition to PEG uptake, an important impairment of nutrient uptake and a different regulation of carbon metabolism could be observed compared to No-W plants. No-W plants showed an important redistribution of antioxidants and assimilates to the root tissue, with a distinctive increase in root proline degradation and alkaline invertase activity. On the contrary, salinity provoked an increase in leaf starch and isocitrate dehydrogenase activity, suggesting key roles in the plant response to this stress. Overall, results suggest higher protection of salt-stressed shoots and non-irrigated roots through different mechanisms, including the regulation of proline and carbon metabolism, while discarding PEG as safe mimicker of drought. This raises the need to understand the effect at the whole plant level of the different strategies employed to apply water-deficit stress.

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Comparison of the Drought Stress Responses of Tolerant and Sensitive Wheat Cultivars During Grain Filling: Changes in Flag Leaf Photosynthetic Activity, ABA Levels, and Grain Yield

Journal of Plant Growth Regulation ◽

10.1007/s00344-009-9085-8 ◽

2009 ◽

Vol 28 (2) ◽

pp. 167-176 ◽

Cited By ~ 67

Author(s):

Adrienn Guóth ◽

Irma Tari ◽

Ágnes Gallé ◽

Jolán Csiszár ◽

Attila Pécsváradi ◽

...

Keyword(s):

Drought Stress ◽

Grain Yield ◽

Stress Responses ◽

Photosynthetic Activity ◽

Flag Leaf ◽

Grain Filling ◽

Wheat Cultivars

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Effect of Exogenous Abscisic Acid on psbA Expression at Grain Filling Stage in Two Wheat Cultivars Under Drought Stress

Acta Agronomica Sinica ◽

10.1016/s1875-2780(11)60038-2 ◽

2011 ◽

Vol 37 (8) ◽

pp. 1372-1377

Author(s):

Yue-Xia WANG ◽

Biao SUO ◽

Peng-Fei ZHAO ◽

Xiao-Fei QU ◽

Li-Gang YUAN ◽

...

Keyword(s):

Abscisic Acid ◽

Drought Stress ◽

Grain Filling ◽

Wheat Cultivars ◽

Filling Stage ◽

Grain Filling Stage

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Global Transcriptome and Weighted Gene Co-expression Network Analyses of Growth-Stage-Specific Drought Stress Responses in Maize

Frontiers in Genetics ◽

10.3389/fgene.2021.645443 ◽

2021 ◽

Vol 12 ◽

Author(s):

Songtao Liu ◽

Tinashe Zenda ◽

Anyi Dong ◽

Yatong Yang ◽

Nan Wang ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Transcriptome Analysis ◽

Stress Responses ◽

Growth Stage ◽

Molecular Mechanisms ◽

Grain Filling ◽

Growth Stages ◽

Specific Response ◽

Network Analyses

Drought is the major abiotic stress threatening maize (Zea mays L.) production globally. Despite recent scientific headway in deciphering maize drought stress responses, the overall picture of key genes, pathways, and co-expression networks regulating maize drought tolerance is still fragmented. Therefore, deciphering the molecular basis of maize drought tolerance remains pertinent. Here, through a comprehensive comparative leaf transcriptome analysis of drought-tolerant hybrid ND476 plants subjected to water-sufficient and water-deficit treatment conditions at flared (V12), tasseling (VT), the prophase of grain filling (R2), and the anaphase of grain filling (R4) crop growth stages, we report growth-stage-specific molecular mechanisms regulating maize drought stress responses. Based on the transcriptome analysis, a total of 3,451 differentially expressed genes (DEGs) were identified from the four experimental comparisons, with 2,403, 650, 397, and 313 DEGs observed at the V12, VT, R1, and R4 stages, respectively. Subsequently, 3,451 DEGs were divided into 12 modules by weighted gene co-expression network analysis (WGCNA), comprising 277 hub genes. Interestingly, the co-expressed genes that clustered into similar modules exhibited diverse expression tendencies and got annotated to different GO terms at different stages. MapMan analysis revealed that DEGs related to stress signal transduction, detoxification, transcription factor regulation, hormone signaling, and secondary metabolites biosynthesis were universal across the four growth stages. However, DEGs associated with photosynthesis and amino acid metabolism; protein degradation; transport; and RNA transcriptional regulation were uniquely enriched at the V12, VT, R2, and R4 stages, respectively. Our results affirmed that maize drought stress adaptation is a growth-stage-specific response process, and aid in clarifying the fundamental growth-stage-specific mechanisms regulating drought stress responses in maize. Moreover, genes and metabolic pathways identified here can serve as valuable genetic resources or selection targets for further functional validation experiments.

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Contrasting response of biomass and grain yield to severe drought in Cappelle Desprez and Plainsman V wheat cultivars

PeerJ ◽

10.7717/peerj.1708 ◽

2016 ◽

Vol 4 ◽

pp. e1708 ◽

Cited By ~ 11

Author(s):

Kenny Paul ◽

János Pauk ◽

Zsuzsanna Deák ◽

László Sass ◽

Imre Vass

Keyword(s):

Drought Stress ◽

Grain Yield ◽

Electron Transport Rate ◽

Biomass Accumulation ◽

Grain Filling ◽

Photosynthetic Parameters ◽

Wheat Cultivars ◽

Flag Leaves ◽

Use Efficiency ◽

Grain Filling Period

We report a case study of natural variations and correlations of some photosynthetic parameters, green biomass and grain yield in Cappelle Desprez and Plainsman V winter wheat (Triticum aestivumL.) cultivars, which are classified as being drought sensitive and tolerant, respectively. We monitored biomass accumulation from secondary leaves in the vegetative phase and grain yield from flag leaves in the grain filling period. Interestingly, we observed higher biomass production, but lower grain yield stability in the sensitive Cappelle cultivar, as compared to the tolerant Plainsman cv. Higher biomass production in the sensitive variety was correlated with enhanced water-use efficiency. Increased cyclic electron flow around PSI was also observed in the Cappelle cv. under drought stress as shown by light intensity dependence of the ratio of maximal quantum yields of Photosystem I and Photosystem II, as well by the plot of the Photosystem I electron transport rate as a function of Photosystem II electron transport rate. Higher CO2uptake rate in flag leaves of the drought-stressed Plainsman cv. during grain filling period correlates well with its higher grain yield and prolonged transpiration rate through spikes. The increase in drought factor (DFI) and performance (PI) indices calculated from variable chlorophyll fluorescence parameters of secondary leaves also showed correlation with higher biomass in the Cappelle cultivar during the biomass accumulation period. However, during the grain filling period, DFI and PI parameters of the flag leaves were higher in the tolerant Plainsman V cultivar and showed correlation with grain yield stability. Our results suggest that overall biomass and grain yield may respond differentially to drought stress in different wheat cultivars and therefore phenotyping for green biomass cannot be used as a general approach to predict grain yield. We also conclude that photosynthetic efficiency of flag and secondary leaves is correlated with grain yield and green biomass, respectively. In addition, secondary trait associated mechanisms like delayed senescence and higher water-use efficiency also contribute to biomass stability. Our studies further prove that photosynthetic parameters could be used to characterize environmental stress responses.

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