Molecular Plant
Volume 6, Issue 2, March 2013, Pages 396-410
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Research Article
The RdDM Pathway Is Required for Basal Heat Tolerance in Arabidopsis

https://doi.org/10.1093/mp/sst023Get rights and content
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ABSTRACT

Heat stress affects epigenetic gene silencing in Arabidopsis. To test for a mechanistic involvement of epigenetic regulation in heat-stress responses, we analyzed the heat tolerance of mutants defective in DNA methylation, histone modifications, chromatin-remodeling, or siRNA-based silencing pathways. Plants deficient in NRPD2, the common second-largest subunit of RNA polymerases IV and V, and in the Rpd3-type histone deacetylase HDA6 were hypersensitive to heat exposure. Microarray analysis demonstrated that NRPD2 and HDA6 have independent roles in transcriptional reprogramming in response to temperature stress. The misexpression of protein-coding genes in nrpd2 mutants recovering from heat correlated with defective epigenetic regulation of adjacent transposon remnants which involved the loss of control of heat-stress-induced read-through transcription. We provide evidence that the transcriptional response to temperature stress, at least partially, relies on the integrity of the RNA-dependent DNA methylation pathway.

SUMMARY

This work shows that a successful heat response depends on the integrity of epigenetic pathways and provides evidence that heat-dependent gene expression is influenced by closely located transposon sequences and read-through transcription.

Key words

heat stress
RNA-directed DNA methylation
transposons
read-through transcription

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Published by the Molecular Plant Shanghai Editorial Office in association with Oxford University Press on behalf of CSPB and IPPE, SIBS, CAS.

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