Characterization of a Novel DWD Protein that Participates in Heat Stress Response in Arabidopsis

Abstract

Cullin4-RING ubiquitin ligase (CRL4) is a family of multi-subunit E3 ligases. To investigate the possible involvement of CRL4 in heat stress response, we screened T-DNA insertion mutants of putative CRL4 substrate receptors that exhibited altered patterns in response to heat stress. One of the mutants exhibited heat stress tolerance and was named heat stress tolerant DWD1 (htd1). Introduction of HTD1 gene into htd1-1 led to recovery of heat sensitivity to the wild type level, confirming that the decrease of HTD1 transcripts resulted in heat tolerance. Therefore, HTD1 plays a negative role in thermotolerance in Arabidopsis. Additionally, HTD1 directly interacted with DDB1a in yeast two-hybrid assays and associated with DDB1b in vivo, supporting that it could be a part of a CRL4 complex. Various heat-inducible genes such as HSP14.7, HSP21, At2g03020 and WRKY28 were hyper-induced in htd1-1, indicating that HTD1 could function as a negative regulator for the expression of such genes and that these genes might contribute to thermotolerance of htd1-1, at least in part. HTD1 was associated with HSP90-1, a crucial regulator of thermotolerance, in vivo, even though the decrease of HTD1 did not affect the accumulation pattern of HSP90-1 in Arabidopsis. These findings indicate that a negative role of HTD1 in thermotolerance might be achieved through its association with HSP90-1, possibly by disturbing the action of HSP90-1, not by the degradation of HSP90-1. This study will serve as an important step toward understanding of the functional connection between CRL4-mediated processes and plant heat stress signaling.

The rolB plant oncogene affects multiple signaling protein modules related to hormone signaling and plant defense

“…Another protein upregulated in the transformed cells was DWD1/HTD1. This protein was shown to participate in heat stress responses, possibly by interacting with Hsp90-1 42 . Enzymes that participate in secondary metabolism, such as chalcone-flavonone isomerase 1 and ATP sulfurylase 4, were upregulated.…”

Selection of reference genes suitable for normalization of qPCR data under abiotic stresses in bioenergy crop Arundo donax L.

“…On the other hand, geNorm classified RPN6 as the best reference gene also in root, making the choice difficult in this context. These results are very interesting, giving the fact that until now, this gene was considered as possible reference gene in quantitative RT-PCR only in Arabidopsis 41 – 43 but, to our knowledge, never in monocot species. Its putative orthologue in Arabidopsis ( AT1G29150 ) encodes a protein constituting a lid subunit of the 26 S proteasome, which is involved in the ubiquitin-proteasome system (UPS) for degradation of misfolded proteins and for stress response 44 .…”

Comparative transcriptome analysis reveals potential evolutionary differences in adaptation of temperature and body shape among four Percidae species

“…Likewise, the “Cul4-RING E3 ubiquitin ligase complex” was also significantly enriched and positively selected. A study on Arabidopsis revealed that Cullin4-RING ubiquitin ligase participates in heat stress response through its association with HSP90-1 [97]. Meanwhile, the RING-type E3 in rice promoted tolerance of heat stress via mediating re-localization of nuclear proteins [98, 99].…”