Pfam domain adaptation profiles reflect plant species' evolutionary history

The increase in global temperatures predicted by climate change models presents a serious problem for agriculture because high temperatures reduce crop yields. Protein biochemistry is at the core of plant heat stress response, and understanding the interactions between protein biochemistry and temperature will be key to developing heat-tolerant crop varieties. Current experimental studies of proteome-wide plant thermostability are limited by the complexity of plant proteomes: evaluating function for thousands of proteins across a variety of temperatures is simply not feasible with existing technologies. In this paper, we use homologous prokaryote sequences to predict plant Pfam temperature adaptation and gain insights into how thermostability varies across the proteome for three species: maize, Arabidopsis, and poplar. We find that patterns of Pfam domain adaptation across organelles are consistent and highly significant between species, with cytosolic proteins having the largest range of predicted Pfam stabilities and a long tail of highly-stable ribosomal proteins. Pfam adaptation in leaf and root organs varies between species, and maize root proteins have more low-temperature Pfam domains than do Arabidopsis or poplar root proteins. Both poplar and maize populations have an excess of low-temperature mutations in Pfam domains, but only the mutations identified in poplar accessions have a negative effect on Pfam temperature adaptation overall. These Pfam domain adaptation profiles provide insight into how different plant structures adapt to their surrounding environment and can help inform breeding or protein editing strategies to produce heat-tolerant crops.

Alterations in the root proteomes of Brassica napus cultivars under salt stress

Soil salinization is an important environmental problem affecting agricultural production worldwide. Seed germination is a critical process, and seedling establishment under saline conditions can be achieved by successful germination. In the present study, comparative proteomics combined with physiological analyses were used to investigate the protein alterations in germinating Brassica napus cultivars (Caravel and Sary) under NaCl stress. Seed germination declined with the increasing NaCl concentration. However, Caravel exhibited better performance in terms of seed germination and seedling growth under salinity stress. Therefore, Caravel was found to be more tolerant to salinity than Sary. The root proteins were extracted from B. napus cultivars germinating on a plant growth medium with or without 100 mM NaCl for seven days. After the root proteins had been separated by two-dimensional (2-D) gel electrophoresis, the differentially accumulated proteins were identified using MALDI-TOF/TOF MS. The comparative proteomics analysis revealed 12 and 27 statistically significant proteins accumulated in the NaCl-treated roots of Caravel and Sary, respectively. The identified proteins were mostly involved in protein metabolism, stress defense, cytoskeleton and cell wall metabolism, and energy metabolism. The salt-sensitive cultivar Sary displayed an elevated accumulation of proteins involved in antioxidant defense and the protein catabolic process such as superoxide dismutase [Fe], L-ascorbate peroxidase 1, and different components of the proteasome system. On the other hand, the levels of molecular chaperones including 20 kDa chaperonin, chaperonin CPN60, heat shock cognate protein HSC70, and heat shock 70 kDa protein 1 were higher in Caravel than Sary under salt stress. These findings will provide the possible mechanisms which contribute to salt tolerance and may serve as the basis for improving salinity tolerance in rapeseed.

Investigation of Echinacea purpurea Root Proteins with Hemagglutinating Activity

Proteins were extracted and fractionated from Echinacea purpurea L. (Moench) (purple coneflower) roots, to evaluate their hemagglutinating activity. Our data suggests that the ~ 25 kDa glycosylated protein is responsible for the hemagglutinating activity and might be worth for its investigation for other biological activities.