A mutation in the Cap Binding Protein 20 gene confers drought

Abstract

In a genetic screen for Arabidopsis mutants displaying pleiotropic alterations in vegetative development and stress responses we have identified a T-DNA insertion mutation in the Cap Binding Protein 20 (CBP20) gene, that encodes the 20kDa subunit of the nuclear mRNA cap binding complex (nCBC). Plants homozygous for the recessive cbp20 mutation show mild developmental abnormalities, such as serrated rosette leaves, delayed development and slightly reduced stature. Loss of the cbp20 function also confers hypersensitivity to abscisic acid during germination, significant reduction of stomatal conductance and greatly enhanced tolerance to drought. Expression of the wild type cDNA by CaMV35S promoter provides full genetic complementation of the pleiotropic cbp20 phenotype. Phenotypic characteristics of the cbp20 mutant are very similar to those of recently described abh1 mutant that is defective in the 80kDa subunit of nCBC. Our data thus confirm that both genes are dedicated to the same function. CBP20 provides a new target for breeding efforts that aim at the improvement of drought tolerance in plants. Our results also show that screening for pleiotropic phenotypes in mutant plant populations may be a fruitful strategy to isolate genes for agronomically important traits.

Characterization of EMU, the Arabidopsis homolog of the yeast THO complex member HPR1

“…The observed genetic interactions between emu and se-1 may provide a clue to the mechanism of action of EMU. Interestingly, mutations in the Arabidopsis genes that encode the two cap-binding complex (CBC) subunits-CAP-BINDING PROTEIN20 (CBP20) and ABSCISIC ACID HYPERSESITIVE1 (ABH1)/CBP80-cause a serrated leaf phenotype and mRNA splicing defects as observed in emu and se-1 mutants (Hugouvieux et al 2001;Papp et al 2004;Kuhn et al 2007;Laubinger et al 2008;Raczynska et al 2010). It is also noteworthy that the abh1-8 mutation enhanced the phyllotaxy defect of ago1-38 mutant inflorescences as seen in emu ago1-27 plants (Gregory et al 2008).…”

“…The intensity of the hybridization signal relative to WT is indicated and was calculated after normalization to rRNA. (Hugouvieux et al 2001;Bezerra et al 2004;Papp et al 2004). These observations raise the possibility that EMU is involved in connecting SE and CBC, which are involved in miRNA biogenesis but do not appear to interact directly with each other (Gregory et al 2008;Kim et al 2008;Laubinger et al 2008).…”

Low and high ψ ways from post-transcriptional RNA regulation to drought tolerance

“…On the contrary in Arabidopsis nCBC mutants are viable, display ABA hypersensitivity, develop with slight morphological abnormalities and exhibit drought tolerance. 16,17 Recent studies have shed light on the molecular details of nCBC function in plants, participating in pre-mRNA splicing and pri-miRNA processing. [18][19][20][21] Although transcription levels of only a few genes have changed in these mutants, splicing of a large set of genes and miRNA pools were profoundly affected.…”

“…26 A decrease in stomatal conductance was also observed in the cbp20 mutant. 17 Improved functioning of stomata may result from sensitization of closure mechanisms, orchestrated by ABA.…”

C-Repeat Binding Factor and Dehydrin Genes are Induced Co-Ordinately in Drought Tolerance Response of Wheat Cultivars

“…hormone regulates, such as germination, growth retardation or other stress responses leading to tolerance. Although these responses probably do not use the same set of signalling components, ABA sensitivity at germination for instance was found to be associated with enhanced drought tolerance in a number of cases (Cutler et al, 1996;Hugouvieux et al, 2001;Papp et al, 2004). Measuring retardation of root elongation at the seedling stage is a relatively simple way to characterize responsiveness to exogenously applied ABA (Thole et al, 2014).…”