Projects / Programmes
Evaluation of common bean (Phaseolus vulgaris L.) genotypes for selected genes conferring drought resistance
| Code |
Science |
Field |
Subfield |
| 4.03.00 |
Biotechnical sciences |
Plant production |
|
| Code |
Science |
Field |
| B225 |
Biomedical sciences |
Plant genetics |
Ph. vulgaris, drought, serin proteases, drought resistance genes, evaluation, molecular markers, genetic maps
Researchers (15)
Organisations (2)
Abstract
Common bean (Phaseolus vulgaris L.) is, worldwide as in Slovenia, one of the most nutritionally important legumes. Its importance has been underlined by the recent formation of an international consortium to improve the quality, yield, and resistance to stress and disease of common beans. Beans provide an important source of protein, vitamins, and minerals and is characterised by a comparatively high content of protein containing essential amino acids, thus has great potential in Europe as a healthy replacement for meat. Common bean is therefore an important component of quality diets and it is essential that effective measures be taken to maintain and improve its yield and quality. In the light of current climatic fluctuation, agricultural production in general in Europe, including Slovenia, is subject to periods of drought and flooding. Thus, across all farming systems, biotic and abiotic stresses increasingly constitute major constraints on the production and economic yield of common bean. It is an important contributor to reduced yields of food legumes. It is important to obtain, by classical breeding or genetic engineering approaches, cultivars more resistant to stress, which will at the same time be economically interesting. In order to achieve this, it is necessary to understand the mechanisms of response to stress of different Phaseolus species and cultivars, in terms of differences in their genetic background. Differential gene expression is among the prerequisites for plant success. One important consequence of changes in gene expression could be a change in proteolytic activity, which affects protein breakdown, known to be essential for adaptation to environmental conditions. Proteases are involved in modifying protein content during conditions that require change of metabolic status or removal of damaged proteins, but also in uncontrolled proteolysis. In order to understand their role, it is important to characterise in more detail the proteolytic activities already identified in our previous study as being involved in the response to drought, with the final aim of determining the basis of their activity at the gene, mRNA and protein levels. Recognizing the enormous potential of DNA markers in plant breeding, marker technology has been adopted. The objective of the proposed research is identification of drought response genes and the preparation of a mapping population, which is the most important step in linkage map construction. This includes the selection of parental, locally adapted common bean genotypes from the gene bank at the Agricultural Institute of Slovenia that differ primarily in drought stress response, as well as other agriculturally important traits, using morphometric, biochemical and molecular marker approaches.
Significance for science
An appropriate response to external stimuli at the cellular level is of fundamental importance to the continuing existence of plants, particularly in the case of stress from adverse environmental conditions. Plants have therefore developed both physiological and biochemical mechanisms that enable their survival which, although extensively studied, are far from completely understood. The results of our project are showing significant contribution for understanding the response of a common bean (Phaseolus vulgaris) to drought, which is a major limiting factor in crop production.
Although the main thrust of the present project is towards creating plants that are more resistant to drought, the biochemical and genetic investigations that are necessary to achieve this end are leading to important basic understanding of elements of the mechanisms of plant resistance, such as differential display of genes and activity of proteolytic enzymes.
The expression of many genes is altered under the influence of drought in some model plants. The data of this project are among the first results that are published for the common bean. At least six transcripts corresponded to those whose expression is altered under drought in Arabidopsis thaliana. Five of the genes identified have not previously been reported as being influenced by drought. None of the identified genes corresponded to those influenced by drought in roots of P. Although it is well known that proteases play an important role in the life, defence mechanisms and senescence of plants, relatively little is known about their involvement in response to drought.
The project results, which showed more involved serine endo-and aminopeptidases, present a new important step in understanding the process of regulation of protein degradation in drought. In particular, a phenilalanine aminopeptidases from bean leaves, which are among the few so far described serine aminopeptidases. Mentioned phenilalanine aminopeptidases are very rare in plants. The basis for further research was made through the identification of proteolytic enzymes encoded by genes and their role in the response to drought.
The results of the project are showing the way for comparison of gene expression and activity of proteolytic enzymes in bean species and varieties of different sensitivity and will allow a detailed understanding of specific cellular mechanisms in the expression of genes for resistance. There is also the possibility of improving resistance of plants transformed with genes that are naturally present in plants. In order to design effective systems for modified plants on the level of genes and to predict the consequences, it is essential to make completely understanding of metabolic processes and their controls. In addition, we have selected and developed populations for the mapping, which is the basis and most important part for future genetic and QTL mapping. First scientific results were allready published in respected journals, the rest of them are being prepared for publication.
Significance for the country
In the strategy for and documentation on development of Slovene agriculture, the direction is defined as creating sustainable production of quality, affordable foodstuffs. Methods of production that ensure preservation of soil fertility, protection of the environment, conservation of biotic diversity and traditional country regions are defined in the National programme of environment protection. Quality assortment, which should be adapted to local conditions and, at the same time has to be appropriate to the taste of the local consumer, is the basis for competitive and sustainable production of any agricultural crop. Selection of a common bean was made by intention, because of the importance of its nutritional and economic value.
On the other hand, periods of drought become more and more frequent in Slovenia. For this reason a study of the response of crops to drought, especially in the biochemical and molecular biological level, is becoming very important for Slovenian agriculture. The development of new plant varieties that would provide appropriate yield in crop production in Slovenian drought conditions, is for Slovenian breeding experts a big challenge, because water is one of the main limiting factors in agriculture and its deficit can significantly reduce crop yield.
With this project, we introduce the use of genetic maps with genetic markers that indicate the quantitative traits loci (QTL) associated with drought in common beans. Genetic maps for many important agricultural traits were shown as a major advance in the breeding processes. Exploitation of the information derived from the map position of traits with agronomical importance and of the linked molecular markers, can be achieved through marker assisted selection (MAS) of the traits during the breeding process. In general and for our plant breeding programs, the most useful application of MAS is to use DNA-based markers for basically three purposes: (1) tracing favorable allele(s) (dominant or recessive) across generations; in order to accumulate favorable alleles, (2) identifying the most suitable individuals among segregating progenies, based on the allelic composition of a part or of the entire genome and (3) breaking the possible linkage of favorable alleles with undesirable loci.
The application of QTL analysis offers unprecedented opportunities to identify chromosome regions controlling variations in almost all the physiological, morphological and developmental changes observed during plant growth in water-limiting conditions. In the present research mapping populations were prepared and underlie and are to be used for genetic mapping of common bean. Our aim in the future is to discover QTLs affecting yield under drought or the expression of drought tolerance-related traits. This would allow us to accumulate the most effective QTLs into elite genotypes. This strategy will lead to new cultivars with high yield potential and high yield stability that in turn will result in superior performance in dry environments.
Most important scientific results
Annual report
2008,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2008,
final report,
complete report on dLib.si
