Articles
THE STUDY OF SELF-(IN)COMPATIBILITY IN CEBAS-CSIC ALMOND BREEDING PROGRAMME
Article number
967_20
Pages
171 – 180
Language
English
Abstract
Although gametophytic self-incompatibility appears to be the ancestral reproductive state in almond, cultivars with a self-compatible phenotype have also been identified mainly in Apulia (Italy). Due to the several advantages of self-compatibility, crossing strategies using self-compatible cultivars or selections have been performed in the CEBAS-CSIC breeding programme to ensure this character in the progenies.
By one of these strategies homozygous self-compatible individuals were experimentally obtained, which in some cases showed inbreeding depression effects mainly affecting endosperm development.
Through the selection process, self-compatibility has been detected using different methods.
From these, the PCR of S-RNases allows an early selection of the seedlings and is routinely applied in our breeding programme.
In the last years, primers that allow a more accurate identification of the S-genotype have been generated.
Thus, using two sets of consensus primers 30 S-RNases were characterised for the first and second intron in plant material mostly from CEBAS-CSIC almond germplasm collection.
Later, the cloning and sequencing of these S-RNases confirmed the existence of new alleles, allowed the resolution of synonyms, the correction of S-genotypes, and consequently to update the table of cross-incompatibility groups.
Amino acid sequence comparison revealed the occurrence of intragenic recombination and indicated the significance of the region between RC4 and C5 in defining specificity.
Recently, it has been found that the absence of ribonuclease activity in the almond Sf-RNase could be explained by the action of other factor(s) involved in the functioning of the self-incompatibility system, which have yet to be identified.
A comparative analysis of the differential expression of proteins in pollen and pistil tissue following compatible and incompatible crosses using 2D-DIGE and HPLC-MS/MS techniques revealed the existence of 21 candidate proteins up-regulated in the incompatible interactions.
Further research to identify proteins and genes participating in the functioning of SI in almond is in progress.
New late and extra-late flowering self-compatible cultivars have been released and different progenies have been generated both for breeding purposes and for genetic studies.
By one of these strategies homozygous self-compatible individuals were experimentally obtained, which in some cases showed inbreeding depression effects mainly affecting endosperm development.
Through the selection process, self-compatibility has been detected using different methods.
From these, the PCR of S-RNases allows an early selection of the seedlings and is routinely applied in our breeding programme.
In the last years, primers that allow a more accurate identification of the S-genotype have been generated.
Thus, using two sets of consensus primers 30 S-RNases were characterised for the first and second intron in plant material mostly from CEBAS-CSIC almond germplasm collection.
Later, the cloning and sequencing of these S-RNases confirmed the existence of new alleles, allowed the resolution of synonyms, the correction of S-genotypes, and consequently to update the table of cross-incompatibility groups.
Amino acid sequence comparison revealed the occurrence of intragenic recombination and indicated the significance of the region between RC4 and C5 in defining specificity.
Recently, it has been found that the absence of ribonuclease activity in the almond Sf-RNase could be explained by the action of other factor(s) involved in the functioning of the self-incompatibility system, which have yet to be identified.
A comparative analysis of the differential expression of proteins in pollen and pistil tissue following compatible and incompatible crosses using 2D-DIGE and HPLC-MS/MS techniques revealed the existence of 21 candidate proteins up-regulated in the incompatible interactions.
Further research to identify proteins and genes participating in the functioning of SI in almond is in progress.
New late and extra-late flowering self-compatible cultivars have been released and different progenies have been generated both for breeding purposes and for genetic studies.
Authors
E. Ortega, P.J. Martínez-García, F. Dicenta
Keywords
Prunus dulcis, S-genotyping, pollen-pistil interactions, 2D-DIGE, inbreeding depression
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