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Summary Boron toxicity is a world‐wide problem for crops, yet we have a limited understanding of the genetic responses and adaptive mechanisms to this stress in plants.We employed a cross‐species comparison between boron stress‐sensitiveArabidopsis thalianaand its boron stress‐tolerant extremophyte relativeSchrenkiella parvula, and a multi‐omics approach integrating genomics, transcriptomics, metabolomics and ionomics to assess plant responses and adaptations to boron stress.Schrenkiella parvulamaintains lower concentrations of total boron and free boric acid than Arabidopsis when grown with excess boron.Schrenkiella parvulaexcludes excess boron more efficiently than Arabidopsis, which we propose is partly driven by SpBOR5, a boron transporter that we functionally characterize in this study. Both species use cell walls as a partial sink for excess boron. When accumulated in the cytoplasm, excess boron appears to interrupt RNA metabolism. The extremophyteS. parvulafacilitates critical cellular processes while maintaining the pool of ribose‐containing compounds that can bind with boric acid.TheS. parvulatranscriptome is pre‐adapted to boron toxicity. It exhibits substantial overlaps with the Arabidopsis boron‐stress responsive transcriptome. Cell wall sequestration and increases in global transcript levels under excess boron conditions emerge as key mechanisms for sustaining plant growth under boron toxicity.
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Positive selection and heat‐response transcriptomes reveal adaptive features of the Brassicaceae desert model, Anastatica hierochuntica
Summary Plant adaptation to a desert environment and its endemic heat stress is poorly understood at the molecular level. The naturally heat‐tolerant Brassicaceae speciesAnastatica hierochunticais an ideal extremophyte model to identify genetic adaptations that have evolved to allow plants to tolerate heat stress and thrive in deserts.We generated anA. hierochunticareference transcriptome and identified extremophyte adaptations by comparingArabidopsis thalianaandA. hierochunticatranscriptome responses to heat, and detecting positively selected genes inA. hierochuntica.The two species exhibit similar transcriptome adjustment in response to heat and theA. hierochunticatranscriptome does not exist in a constitutive heat ‘stress‐ready’ state. Furthermore, theA. hierochunticaglobal transcriptome as well as heat‐responsive orthologs, display a lower basal and higher heat‐induced expression than inA. thaliana. Genes positively selected in multiple extremophytes are associated with stomatal opening, nutrient acquisition, and UV‐B induced DNA repair while those unique toA. hierochunticaare consistent with its photoperiod‐insensitive, early‐flowering phenotype.We suggest that evolution of a flexible transcriptome confers the ability to quickly react to extreme diurnal temperature fluctuations characteristic of a desert environment while positive selection of genes involved in stress tolerance and early flowering could facilitate an opportunistic desert lifestyle.
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- PAR ID:
- 10373252
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 236
- Issue:
- 3
- ISSN:
- 0028-646X
- Page Range / eLocation ID:
- p. 1006-1026
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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