Overexpression of oligouridylate binding protein 1b results in ABA hypersensitivity

Abstract

Oligouridylate binding protein 1b (UBP1b), a marker protein of plant stress granules (SGs), plays a role in heat stress tolerance in plants. A previous microarray analysis revealed that the expression of several ABA signaling-related genes is higher in UBP1b-overexpressing Arabidopsis plants (UBP1b-ox) subjected to both non-stressed and heat stress conditions. Root elongation and seed germination assays demonstrated that UBP1b-ox exhibited hypersensitivity to ABA. RT-qPCR analysis confirmed that mitogen-activated protein kinase (MAPK) cascade genes, such as MPK3, MKK4, and MKK9 were upregulated in UBP1b-ox plants. ABA receptor genes, including PYL5 and PYL6, were also upregulated in UBP1b-ox plants. mRNA of WRKY33 -a downstream gene of MPK3 and an upstream gene of ethylene biosynthesis, exhibited high levels of accumulation, although the level of endogenous ABA was not significantly different between UBP1b-ox and control plants. In addition, RNA decay analysis revealed that WRKY33 was more stable in UBP1b-ox plants, indicating that the mRNA of WRKY33 was protected within UBP1b SGs. Collectively, these data demonstrate that UBP1b plays an important role in plant response to ABA.

Ethylene involvement in the regulation of heat stress tolerance in plants

“…Another protein, the oligouridylate-binding protein 1b (UBP1b) plays also an important role in plant heat stress tolerance by protecting mRNAs from degradation. The RT-qPCR analysis showed that expression of ABA signaling-related genes and genes of ET biosynthesis (ACS6, ACS7, ACS8, and ACS11) were higher in UBP1b-overexpressing Arabidopsis plants (Nguyen et al 2017). It can be concluded that ET, ABA, JA, and SA are rapidly accumulated by heat stress but with different kinetics depending on the plant species, the strength of heat, or other environmental factors such as light intensity.…”

Polysomes, Stress Granules, and Processing Bodies: A Dynamic Triumvirate Controlling Cytoplasmic mRNA Fate and Function

“…UBP1A and UBP1C reversibly aggregate Gloggnitzer et al (2014) into cytoplasmic poly(A) mRNA granules upon hypoxic and heat stress (Sorenson and Bailey-Serres, 2014). Similarly, UBP1B reversibly forms SGs under heat stress and plays a crucial role in ABA signaling and heat stress tolerance (Nguyen et al, 2016(Nguyen et al, , 2017). An analysis of RNA decay kinetics suggested that UBP1B complexes (UBP1B-SGs) protect stress-related mRNAs from degradation during heat stress (Nguyen et al, 2016).…”

Arabidopsis thaliana G3BP Ortholog Rescues Mammalian Stress Granule Phenotype across Kingdoms

“…Of the Arabidopsis RBP45/47 family, RBP47B relocates from the nucleus to cytoplasmic foci in response to heat, salt and hypoxic stress [7,[36][37][38]. UBP1B localizes to SGs under heat stress and plays a crucial role in phytohormone signaling and heat-stress tolerance [39,40]. AtG3BP-2 condenses into SGs and interacts with the nuclear shuttle protein of the begomovirus Abutilon mosaic virus and Pea necrotic yellow dwarf virus upon heat stress [18].…”