Multilevel regulation of seed dormancy and germination in hexaploid wheat revealed through proteogenomic, redox proteomic, and biochemical approaches


Bykova NV, Radovanovic N, Huang M, Rampitsch M, Yao Z, Wijesinghe MKPS, Junjie Hu-Skrzenta J (2023) Multilevel regulation of seed dormancy and germination in hexaploid wheat revealed through proteogenomic, redox proteomic, and biochemical approaches. The 5th Conference of the International Plant Proteomics Organization – ThessInPPO2023, Thessaloniki, Central Macedonia, Greece, May 22-25, 2023.


Seed dormancy control in wheat is complex, and genetic factors responsible for it are dispersed on almost every wheat chromosome. Consistent with the genetic complexity is wide range of physiological and physical attributes affecting dormancy. Generation of reactive oxygen species (ROS), antioxidative systems, phytohormonal regulation and their reciprocal signaling play important roles in releasing embryo cells from the quiescent state during seed dormancy removal. In this study, proteins and genes essential to regulation of dormant or high germination potential physiological states, ROS-mediated modification of redox responding proteins, and antioxidant systems involved in governing complex seed dormancy trait were revealed. Hard white spring wheat (Triticum aestivum L.) doubled haploid population and integration of proteogenomic, pharmacological, quantitative thiol-specific redox proteomic, and biochemical approaches were employed. In dormant embryos, phenotype-specific alterations were found for proteins involved in modulation of ROS in cell wall, extracellular compartment, and mitochondria. Proteomic signatures of dormancy phenotype consisted of signaling proteins associated with flowering, downstream targets of ABA-dependent germination repression pathway, enzymes responsible for alteration of intracellular ABA levels and structural integrity of plant cell wall. Induction of early germination in embryos was accompanied by higher capacity for the provision of NADPH reducing equivalents for biosynthetic processes, generation of lipid second messengers, protein targeting to 26S proteasome, positive modulation of GA signaling, and regulation of osmosensory responses. Inhibition of ROS production in the presence of ABA had synergistic effect on blocking germination in non-dormant seeds. Our results demonstrate that germination induction is mediated through the redox control, and antioxidative pathways in wheat embryos are involved in dormancy regulation. The total glutathione levels were significantly higher in dormant than in non-dormant embryos, whereas the total ascorbate levels increased upon dormancy release indicating high capacity for ascorbate regeneration and different roles of ascorbate and glutathione in regulation of seed germination.

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