Convergent starvation signals and hormone crosstalk in regulating nutrient mobilization upon germination in cereals.

Abstract

Germination is a unique developmental transition from metabolically quiescent seed to actively growing seedling that requires an ensemble of hydrolases for coordinated nutrient mobilization to support heterotrophic growth until autotrophic photosynthesis is established. This study reveals two crucial transcription factors, MYBS1 and MYBGA, present in rice (Oryza sativa) and barley (Hordeum vulgare), that function to integrate diverse nutrient starvation and gibberellin (GA) signaling pathways during germination of cereal grains. Sugar represses but sugar starvation induces MYBS1 synthesis and its nuclear translocation. GA antagonizes sugar repression by enhancing conuclear transport of the GA-inducible MYBGA with MYBS1 and the formation of a stable bipartite MYB-DNA complex to activate the α-amylase gene. We further discovered that not only sugar but also nitrogen and phosphate starvation signals converge and interconnect with GA to promote the conuclear import of MYBS1 and MYBGA, resulting in the expression of a large set of GA-inducible but functionally distinct hydrolases, transporters, and regulators associated with mobilization of the full complement of nutrients to support active seedling growth in cereals.

• Authors: Ya-Fang Hong, Tuan-Hua David Ho, Chin-Feng Wu, Shin-Lon Ho, Rong-Hwei Yeh, Chung-An Lu, Peng-Wen Chen, Lin-Chih Yu, Annlin Chao, Su-May Yu
• Journal: The Plant cell (Plant Cell) Vol. 24 Issue 7 Pg. 2857-73 (Jul 2012) ISSN: 1532-298X [Electronic] England
• PMID: 22773748 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Gibberellins
• Nuclear Localization Signals
• Phosphates
• Plant Growth Regulators
• Plant Proteins
• Recombinant Fusion Proteins
• Transcription Factors
• Green Fluorescent Proteins
• Carbon
• alpha-Amylases
• Nitrogen

Topics

• Biological Transport
• Carbon (metabolism)
• Cell Nucleus (metabolism)
• Endosperm (genetics, metabolism, physiology)
• Gene Expression Regulation, Plant
• Germination (physiology)
• Gibberellins (metabolism)
• Green Fluorescent Proteins
• Hordeum (genetics, metabolism, physiology)
• Models, Biological
• Mutation
• Nitrogen (metabolism)
• Nuclear Localization Signals
• Oryza (genetics, metabolism, physiology)
• Phosphates (metabolism)
• Plant Growth Regulators (metabolism)
• Plant Proteins (genetics, metabolism)
• Recombinant Fusion Proteins
• Seedlings (genetics, metabolism, physiology)
• Seeds (genetics, metabolism, physiology)
• Signal Transduction (physiology)
• Transcription Factors (genetics, metabolism)
• alpha-Amylases (metabolism)