A proteomic approach was used to identify droughtresponsive proteins in leaves of two cultivars of common bean (Phaseolus vulgaris L.) differing in their response to drought, more sensitive Starozagorski čern and Tiber. 2DDIGE was used to compare differences in protein abundance between control and stressed plants. Fiftyeight proteins whose abundance changed significantly were identified by LCMS/MS in Tiber and 64 in Starozagorski čern. The majority of identified proteins were classified into functional categories that include energy metabolism, photosynthesis, ATP interconversion, protein synthesis and proteolysis, stress and defence related proteins. Details of the function of the identified proteins and their abundance profiles in Tiber and Starozagorski are discussed. Interactions between identified proteins were demonstrated by bioinformatics analysis, enabling a more complete insight into biological pathways and molecular functions affected by drought stress.
COBISS.SI-ID: 3924072
Protein breakdown by proteases is basic to the plant response to abiotic stresses such as drought. A large number of genes encoding proteases or putative proteases exist in plants. Only a few of those involved in the response to drought have been characterized, and their regulation is poorly understood. We have identified two new subtilases from leaves of Phaseolus vulgaris L. cultivar Zorin, PvSLP1 and PvSLP2. PvSLP1 was identified at the gene level, using primers based on the gene sequence of the putative drought induced serine protease from Arachis hypogaea L. In P. vulgaris, expression of the PvSLP1 transcript did not change on water withdrawal. PvSLP2 was isolated and characterized at the protein level, together with complete gene and cDNA sequences. The deduced amino acid sequences of both PvSLP1 and PvSLP2 are characteristic of plant subtilases of the S8 family of clan SB. PvSLP2 shows 33% sequence identity to PvSLP1. Expression of the PvSLP2 transcript did not change on withdrawal of water, but its proteolytic activity in leaves increased, depending on the age and position of the leaf. In addition, the level of activity in senescent leaves of well watered plants was higher than in mature or young leaves. These results, together with the fact that PvSLP2 cleaves peptide bonds following an Arg residue, point to regulation of PvSLP2 subtilase activity at translational and/or posttranslational levels and suggest a specific role in the response to drought and senescence.
COBISS.SI-ID: 26305831
Abiotic stresses with a dehydration component (drought, salt, and freezing) involve, as a common feature, increased numbers of inactive proteins – denatured, aggregated or oxidatively damaged. Maintaining proteins in their functional conformation, preventing aggregation of nonnative proteins, refolding of denatured proteins to their native conformation and removal of nonfunctional and potentially harmful polypeptides are all vital for cell survival under dehydration stress. To achieve this, plants respond to drought by synthesis of protective proteins such as dehydrins and chaperones and by degradation of irreversibly damaged proteins by proteases. Here we review the important cellular functions of dehydrins, chaperones, proteases and protease inhibitors, together with their role in the response to drought, that make them potential biochemical markers for assessing drought tolerance.
COBISS.SI-ID: 3815784
Controlled protein degradation is required for the growth and development of plants and for them to survive abiotic and biotic stresses. Uncontrolled proteolysis, that is often induced by stress, is however deleterious for plants. Proteases are essential for carrying out and regulating protein breakdown, functions that are regulated by specific endogenous protein inhibitors. General information on proteases and their inhibitors is reviewed, followed by descriptions of some of the increasing numbers of reports on their involvement in the plant response to abiotic stress, particularly drought. Levels of proteases are increasingly seen to be associated with the degree of tolerance and sensitivity to abiotic stress. Further definition of the role of proteases in plant stress will thus contribute in establishing the necessary basis for crop improvement.
COBISS.SI-ID: 27830823
Genetic diversity and the population structure of 167 common bean accessions divided into four groups according to geographical origin (Slovenia and Austria) and time periods (historical and present) was evaluated using 14 SSR markers. Great allelic polymorphism was detected in all four groups of examined accessions, indicating that Slovene and Austrian bean germplasm in the past possessed significant variation that has been well preserved until today. In factorial correspondence analysis, accessions from different groups clustered together indicating potential gene flow between countries. The uncovered diversity corresponded very well to the two recognized gene pools (Andean and Mesoamerican). The majority of accessions in every single group belonged to the Andean gene pool. Strong predominance of Andean genotypes classifies Slovenia among other Mediterranean countries, like Spain and Italy. The latter appears as a most probable source of first beans in Slovenia and Austria. We assumed that in the beginning of the previous century after very tight relationships between Slovenia and Austria loosened, introgression of genotypes from western and northern European countries took place in Austria, which resulted in a very high proportion of Mesoamerican genotypes that we found in the present Austrian germplasm (44%).
COBISS.SI-ID: 4208744