Chen, Peilei: Analysis of two selected cell wall proteins and one lncRNA involved in desiccation tolerance of the resurrection plant Craterostigma plantagineum. - Bonn, 2020. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5-57039
@phdthesis{handle:20.500.11811/8257,
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5-57039,
author = {{Peilei Chen}},
title = {Analysis of two selected cell wall proteins and one lncRNA involved in desiccation tolerance of the resurrection plant Craterostigma plantagineum},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2020,
month = jan,

note = {Water deficit is a severe stress negatively affecting plant growth and productivity. Extreme dehydration, termed desiccation, will lead to substantial water loss from cells and eventually results in less than 10% RWC (relative water content). Resurrection plants are a small group of desiccation-tolerant angiosperms, which are able to circumvent or overcome the desiccation stress in their unique ways. Craterostigma plantagineum Hochst. (Scrophulariaceae) is the model resurrection plant for dissecting the mechanisms underlying desiccation tolerance. It can revive after being desiccated for more than two years. The recovery requires cell wall remodeling during dehydration and rehydration. The cell wall protein CpWAK1 (C. plantagineum wall associated kinase 1) is supposed to be involved in cell wall remodeling by forming a CpWAK1-CpGRP1 (C. plantagineum glycine-rich protein 1) complex. This interaction between CpWAK1 and CpGRP1 was demonstrated in yeast and in planta. The activity of the complex was envisaged to be affected by cell wall pectin given that AtWAKs bind to pectins in vivo and in vitro. However, neither the binding of CpWAK1 to pectins nor the role of the CpWAK1-CpGRP1 complex has been investigated. In addition, there are other candidate genes implicated in the resistance to desiccation in C.plantagineum. The cell wall protein gene CpCRP1 (C.plantagineum cysteine-rich protein 1) and the lncRNA 28852 (long non-coding RNA 28852) were taxonomically restricted genes responsive to desiccation. The CpGLP1 (C. plantagineum germin-like protein) was identified as a putative interaction partner of CpCRP1 in a yeast-two-hybrid assay. Like many other GLPs, CpGLP1 also has SOD activity. The interaction between CpGLP1 and CpCRP1 in planta and whether CpGLP1 participates in the cross linking of cell walls under drought still need to be explored. A substantial amount of plant lncRNAs were discovered. Some of them are characterized as target mimicry of miRNAs, precursors of sRNAs or the scaffolds for chromatin modifiers. The newly identified taxonomically restricted gene lncRNA 28852 is induced by dehydration, especially desiccation. However, its functions and the mechanisms it participates in are still obscure.
In this thesis, the main study is focused on CpWAKs. To understand the genome organization and the evolutionary patterns of CpWAKs, the full-length sequences and the upstream and downstream sequences of CpWAK genes were identified using genome-walking. The alignments of CpWAK genes and the phylogenetic analyses using CpWAK protein sequences suggest gene duplications for CpWAK genes after species divergence. The expression profiles of CpWAKs on the transcript and protein levels reveal that CpWAKs are involved in various biological processes, including regulation of the circadian clock, drought-induced responses and SA- and JA-related plant resistance to pathogens and wounding. The interactions of CpWAKs with pectins and CpGRP1 in vitro were demonstrated by ELISA assays. In the presence of DTT no band shift was seen on protein gels. This indicates that the formation of CpWAK multimers is the prerequisite for the CpWAK-pectin linkage. CpGRP1 shows a positive effect on the binding of CpWAKs to pectins in the ELISA assays. This effect was detected at different pH values as well. The CpWAK-pectin binding was determined using different pectin extracts. Different pectin extracts lead to the opposite trend of CpWAK-pectin binding in the presence of Ca2+ CpWAKs are potential sensors which can distinguish the cell wall signals caused by diverse stimuli with the aid of other elements, such as CpGRPs, pHapo, Ca2+ [apo] and the formation of CpWAK multimers or dimers.
Pull-down assays and BiFC assays did not confirm the interaction of CpCRP1 and CpGLP1 in vitro or in planta. But the detection of CpGLP1 in cell wall protein extracts and its accumulation in dehydrated and rehydrated leaves showed that it may also affect the cell wall remodeling during dehydration and rehydration.
The expression of the lncRNA 28852 was analyzed on total and polysomal RNA levels. The lncRNA 28852 is abundantly expressed during desiccation on the total RNA level, while the lncRNA 28852 from polysomal RNA only accumulated during dehydration and rehydration not during desiccation. The opposite accumulation of the lncRNA 28852 implies the interaction of lncRNA 28852 and ribosomes in the early stage of dehydration and rehydration. This interaction is considered an effective protection against RNA degradation and contributes to the accumulation of lncRNA 28852 under desiccation. The down-regulated lncRNA 28852 in polysomal RNA of desiccated leaves indicates that the lncRNA 28852 is presumably not implicated in protein translation during desiccation. Because no similarity to the sequences in the GenBank database was found, Arabidopsis thaliana lines overexpressing the lncRNA 28852 were established for functional analysis. To further uncover possible processes in which the lncRNA 28852 is involved, comparative RNA-seq analysis of wild-type and mutants was performed. The non-repeatable gene expression patterns and the non-conspicuous changes in the phenotypes of the mutants suggest the ineffective role or the intricate effect of C. plantagineum lncRNA 28852 in Arabidopsis thaliana.},

url = {https://hdl.handle.net/20.500.11811/8257}
}

Die folgenden Nutzungsbestimmungen sind mit dieser Ressource verbunden:

InCopyright