ISHS Acta Horticulturae 538: Eucarpia symposium on Fruit Breeding and Genetics
RECENT ADVANCES IN CHERRY SELF-(IN)COMPATIBILITY STUDIES |
| Authors: | R. Boškoviˇc, K.R. Tobutt, T. Sonneveld, Ceroviˇc |
| Keywords: | Prunus avium, ribonucleases, pollen tube growth, allele-specific PCR |
| Abstract:
Three recent advances in cherry self-(in)compatibility are reported. Stylar ribonucleases of cultivars that had previously been assigned to incompatibility groups or to the ‘universal donors’ by work at the John Innes Institute were analysed. Thus the allelic constitutions of groups X, XI and XII and of cultivars belonging to group O, which had not previously been genotyped were resolved. We detected six new groups, XIV-XIX and found four new alleles, S12 to S15. To check the nature of self-compatibility in the John Innes selection JI 2434, stylar ribonucleases of this selection and of the progeny ‘Van’ (S1S3) x JI 2434 were analysed. JI 2434 showed bands for S3 and S4, and the progeny segregated into four classes, rather than two. This indicates the S3 allele of JI 2434 had mutated. We crossed JI 2434 x ‘Napoleon’ (S3S4) and monitored pollen tube growth by fluorescence microscopy. The cross was incompatible. Thus the mutation of S3 in JI 2434 affects its pollen expression, and is denoted S3'. This is the first definite report of the S3' mutant allele. To complement our protein approach we developed a DNA approach. Degenerate primers based on two conserved regions of incompatibility ribonucleases in Prunus were used for amplification of reverse transcribed stylar RNA of various cultivars of known S genotype. Products were cloned and candidate clones for S1 to S6 were sequenced. cDNA sequences were used to design allele-specific primers. These have allowed us to identify S1 to S6 in vegetative material, and to detect, in appropriate crosses, seedlings carrying the self-compatibility alleles S3' and S4'. | |
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