Browsing by Subject "callose synthase"

Despite their immobile nature, their ability for adaptation allows plants to face harmful conditions from the environment to successfully survive and reproduce. Plant cells sense and integrate signals from the environment and activate response mechanisms. Participants in these mechanisms are the receptor-like protein kinases (RLKs) and a subgroup of RLKs, the cysteine-rich receptor-like kinases (CRKs). Members of this family have been associated with functions related to environmental stress responses in plants. CRK2 is one interesting member of the CRK clade of RLKs. While roles of CRK2 in the response to biotic and abiotic stimuli have been recently described, many aspects of the diverse functions of CRK2 remain elusive. The reduced size of the crk2 mutant suggests that developmental processes are affected by the absence of the protein. One of the objectives of this work was to analyse potential reasons for the smaller size of crk2. The difference in plant size could be due to a reduced number of cells. Results from the analysis of young cotyledons showed that the smaller plant size is not due to a reduced cell number in leaves when compared to Arabidopsis thaliana (Arabidopsis) ecotype Columbia (Col-0). Another way to understand the processes in which a protein is involved is to target possible interaction partners. Therefore, genotyping and analysis of growth phenotypes of T-DNA insertion mutant lines for candidate interaction partners for CRK2 was performed. The results revealed smaller phenotype for a nitrate transporter (NRT1.7) mutant in fresh weight and rosette area whereas for a protein kinase (QSK1) mutant, higher fresh weight but reduced rosette area was observed compared to Col-0. Generation of constructs for fusion protein expression and purification revealed the possibility of expressing tagged cytoplasmic regions of these proteins for further analysis of protein-protein interaction through kinase assays due to the kinase activity of CRK2. Generation of fluorescent-tagged proteins from the candidate interaction partners allowed for localization studies via confocal microscopy to determine the co-localization to the plasma membrane of these proteins with CRK2, which is located to plasma membrane under standard growth conditions. The co-localization results suggest that the proteins NRT1.7 and QSK1 colocalize with CRK2, which is a step forward in the verification of their possible interaction in planta. The smaller size of the nrt1.7 and qsk1 mutants indicates that the lack of these proteins affects plant development.