Functional analysis of cold-induced protein PEACI11.8 of pea (Pisum sativum L.)
Date Issued
2005
Date
2005
Author(s)
Shih, Han-Wei
DOI
en-US
Abstract
The pea cold acclimation induced protein PEACI11.8 is a group 2 late embryogenesis abundant protein involved in plant responses to stress. Previous study showed that the accumulation of its transcripts began within 6 hours of cold treatment and peaked between 4 and 10 days of treatment. The expression of this gene was rapidly down-regulated after the acclimated seedlings were transferred to normal ambient temperature. Otherwise, PEACI11.8 was also induced by ABA and PEG treatment. In the first part of this study, we provide evidence of the tissue and cell specificity of PEACI11.8 expression. We performed histochemical analysis of PEACI11.8 using β-glucuronidase (GUS) assays in Arabidopsis. The expression of PEACI11.8 promoter::GUS was detected at high level in shoot apical meristem, root vascular tissue and lateral root initiation zone of unstressed plant. In the 7-d-old stressed plants, whole plants appeared blue and the order of induction is ABA>PEG>NaCl>Cold. In adult plants, intense staining was detected in stigma, suggesting that PEACI11.8 has roles during pollen germination or pollen tube growth. Another intense staining site is abscission zone, these cells (stigma and abscission zone) share the characterization that they are unprotected by mechanical barriers and therefore are susceptible to microbial attack and one ELRE (elicitor response element) cis-element in PEACI11.8 promoter. We suggest that PEACI11.8 may play a secondary role of local defense response in stigma and abscission zone. We also used PEACI11.8 promoter to drive GFP-PEACI11.8 fusion protein in stable transformants to investigate subcellular localization. In T1 seedlings, we observed GFP::PEACI11.8 fusion protein expressed in guard cell, root maturation zones and elongation zones. Unfortunately, only one line treated with ABA (total 23 lines) in T2 seedlings expressed GFP-PEACI11.8 fusion protein in the lateral root initiation zone. This results is consistent to histochemical staining result, suggesting that PEACI11.8 may plays a important role in lateral root cells initiation. In the second part of this study, we used two expression systems to test the contribution of PEACI11.8 to stress tolerance in Saccharomyces cerevisiae and Arabidopsis thaliana. In the Saccharomyces cerevisiae expression system, PEACI11.8 was inserted into a multicopy plasmid under the transcriptional control of the yeast GAL1 promoter, and the expression of PEACI11.8 protein was confirmed by immunochemical methods. Yeast cells expressing PEACI11.8 did not show improved growth in 1.2M NaCl, 1.2M KCl and 4℃. In the Arabidopsis thaliana expression system, PEACI11.8 coding sequence was driven by cauliflower mosaic virus 35S promoter. Transgenic plants showed no differences from wild type in normal or stress conditions.
Subjects
低溫馴化
胚胎成熟晚期第二群富含蛋白質
Cold acclimation
Group 2 LEA protein
Type
other
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