An Arabidopsis homeodomain transcription factor gene, HOS9 , mediates cold tolerance through a CBF-independent pathway

Abstract

To investigate essential components mediating stress signaling in plants, we initiated a large-scale stress response screen using Arabidopsis plants carrying the firefly luciferase reporter gene under the control of the stress-responsive RD29A promoter. Here we report the identification and characterization of a mutant, hos9-1 (for high expression of osmotically responsive genes), in which the reporter construct was hyperactivated by low temperature, but not by abscisic acid or salinity stress. The mutants grow more slowly, and flower later, than do wild-type plants and are more sensitive to freezing, both before and after acclimation, than the wild-type plants. The HOS9 gene encodes a putative homeodomain transcription factor that is localized to the nucleus. HOS9 is constitutively expressed and not further induced by cold stress. Cold treatment increased the level of transcripts of the endogenous RD29A, and some other stress-responsive genes, to a higher level in hos9-1 than in wild-type plants. However, the C repeat͞ dehydration responsive element-binding factor (CBF) transcription factor genes that mediate a part of cold acclimation in Arabidopsis did not have their response to cold altered by the hos9-1 mutation. Correspondingly, microarray analysis showed that none of the genes affected by the hos9-1 mutation are controlled by the CBF family. Together, these results suggest that HOS9 is important for plant growth and development, and for a part of freezing tolerance, by affecting the activity of genes independent of the CBF pathway.

A DEAD Box RNA Helicase Is Critical for Pre-mRNA Splicing, Cold-Responsive Gene Regulation, and Cold Tolerance inArabidopsis

“…Our results show that the defective splicing of SK12 and PRR5 explains at least part of the compensatory response in the rcf1-1 mutant. We have observed a similar phenomenon in hos9-1 and hos15 mutants, which accumulate higher levels of some cold-responsive genes but are hypersensitive to cold stress (Zhu et al, 2004(Zhu et al, , 2008. Unlike rcf1-1, however, hos9-1 and hos15 mutations do not affect cold induction of CBF genes.…”

“…Fully developed rosette leaves were used for electrolyte leakage measurements as described (Sukumaran and Weiser, 1972;Ristic and Ashworth, 1993;Zhu et al, 2004). Whole-plant freezing tests were as described ) with modifications.…”

Relationship between water use efficiency (WUE) and production of different wheat genotypes at soil water deficit

“…WUE and production are related closely related to the redox state in plants, through which plants complete transportation and conversion of photosynthetic products and their life circle, further making plant physiological potential into full use [21,22,26,71,[79][80].…”

“…Drought is a worldwide problem, constraining global crop production and quality seriously and recent global climate Therefore, drought is connected with almost all aspects of biology [71,[79][80][81][82][83]. Currently, drought study has been one of the main directions in global plant biology and biological breeding.…”

Overexpression of the Arabidopsis 10-Kilodalton Acyl-Coenzyme A-Binding Protein ACBP6 Enhances Freezing Tolerance

“…Freezing treatment was carried out following Zhu et al (2004). NA plants were grown in a growth chamber under 16-h-light (23°C)/8-h-dark (21°C) cycles until treatment, while CA plants were transferred from the growth chamber to a cold room (4°C) and grown for 3 d prior to treatment.…”