Abstract
Grain number, plant height, and heading date7 (Ghd7) has been regarded as an important regulator of heading date and yield potential in rice (Oryza sativa). In this study, we investigated functions of Ghd7 in rice growth, development, and environmental response. As a long-day dependent negative regulator of heading date, the degree of phenotypic effect of Ghd7 on heading date and yield traits is quantitatively related to the transcript level and is also influenced by both environmental conditions and genetic backgrounds. Ghd7 regulates yield traits through modulating panicle branching independent of heading date. Ghd7 also regulates plasticity of tiller branching by mediating the PHYTOCHROME B-TEOSINTE BRANCHED1 pathway. Drought, abscisic acid, jasmonic acid, and high-temperature stress strongly repressed Ghd7 expression, whereas low temperature enhanced Ghd7 expression. Overexpression of Ghd7 increased drought sensitivity, whereas knock-down of Ghd7 enhanced drought tolerance. Gene chip analysis of expression profiles revealed that Ghd7 was involved in the regulation of multiple processes, including flowering time, hormone metabolism, and biotic and abiotic stresses. This study suggests that Ghd7 functions to integrate the dynamic environmental inputs with phase transition, architecture regulation, and stress response to maximize the reproductive success of the rice plant.
Highlights
Grain number, plant height, and heading date7 (Ghd7) has been regarded as an important regulator of heading date and yield potential in rice (Oryza sativa)
Molecular evidence revealed that FLOWERING LOCUS T (FT) and TWIN SISTER OF FT (TSF) proteins directly interact with BRANCHED1/TEOSINTE BRANCHED1LIKE1 (BRC1) protein, a homolog of TEOSINTE BRANCHED1 (TB1) (Takeda et al, 2003; Choi et al, 2012), and modulate florigen activity in the axillary buds to prevent premature floral transition of the axillary meristems (Niwa et al, 2013)
We show that the flowering time gene Ghd7 regulates plant architecture and such regulation is dependent on both genetic background and environmental signaling
Summary
Plant height, and heading date (Ghd7) has been regarded as an important regulator of heading date and yield potential in rice (Oryza sativa). This study suggests that Ghd functions to integrate the dynamic environmental inputs with phase transition, architecture regulation, and stress response to maximize the reproductive success of the rice plant. Rice Indeterminate acts as a master switch for the transition from vegetative to reproductive phase and regulates the expression of Ghd independent of the photoperiod Molecular evidence revealed that FT and TSF proteins directly interact with BRANCHED1/TEOSINTE BRANCHED1LIKE1 (BRC1) protein, a homolog of TEOSINTE BRANCHED1 (TB1) (Takeda et al, 2003; Choi et al, 2012), and modulate florigen activity in the axillary buds to prevent premature floral transition of the axillary meristems (Niwa et al, 2013) Our results suggest that Ghd may function as a sensor for the plant to adapt to dynamic environmental inputs and that Ghd is involved in the plant architecture regulation and stress-response pathways
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