The RNase PD2 gene of almond (Prunus dulcis) represents an evolutionarily distinct class of S-like RNase genes

Abstract

A cDNA for an S-like RNase (RNase PD2) has been isolated from a pistil cDNA library of Prunus dulcis cv. Ferragnés. The cDNA encodes an acidic protein of 226 amino acid residues with a molecular weight of 25 kDa. A potential N-glycosylation site is present at the N-terminus in RNase PD2. A signal peptide of 23 amino acid residues and a transmembrane domain are predicted. The two active-site histidines present in enzymes of the T2/S RNase superfamily were detected in RNase PD2. Its amino acid sequence shows 71.2% similarity to RNSI of Arabidopsis and RNase T2 of chickpea, respectively. Northern blotting and RT-PCR analyses indicate that PD2 is expressed predominantly in petals, pistils of open flowers and leaves of the almond tree. Analyses of shoots cultured in vitro suggested that the expression of RNase PD2 is associated with phosphate starvation. Southern analysis detected two sequences related to RNase PD2 in the P. dulcis genome. RFLP analysis showed that S-like RNase genes are polymorphic in different almond cultivars. The PD2 gene sequence was amplified by PCR and two introns were shown to interrupt the coding region. Based on sequence analysis, we have defined three classes of S-like RNase genes, with the PD2 RNase gene representing a distinct class. The significance of the structural divergence of S-like RNase genes is further discussed.

Molecular variation at the self-incompatibility locus in natural populations of the genera Antirrhinum and Misopates

“…Other genes with similar structure to S-RNases, but not linked to the S-locus (the 'S-like RNases'), exist in various plant families including the Solanaceae (Jost et al, 1991;Lö ffler et al, 1993;Kuroda et al, 1994;Dodds et al, 1996;Lers et al, 1998) and Rosaceae (Norioka et al, 1996;Ma and Oliveira, 2000). Recently, two putative S-like RNase RNase sequence.…”

ABA may affect the dormancy in triticale caryopses by inhibition of embryo class I RNases, enzymes involved in Pi release

“…Among ribonucleases, a non-uniform group of enzymes is distinguished, known as S-like RNases. The polymorphism of genes which code them (differences in the DNA sequence and position of loci in chromosomes) shapes not only the species-or cultivar-specific variability but also the tissue specificity (Ma and Oliveira 2000;Kock et al 2006;MacIntosh et al 2010). Acid RNases PD2 (from almond tree) and RSH1 (from barley) of the mass 25 kDa have been classified as belonging to this group of enzymes (Ma and Oliveira 2000;Gausing 2000).…”

“…The polymorphism of genes which code them (differences in the DNA sequence and position of loci in chromosomes) shapes not only the species-or cultivar-specific variability but also the tissue specificity (Ma and Oliveira 2000;Kock et al 2006;MacIntosh et al 2010). Acid RNases PD2 (from almond tree) and RSH1 (from barley) of the mass 25 kDa have been classified as belonging to this group of enzymes (Ma and Oliveira 2000;Gausing 2000). Results of numerous studies confirm that S-like RNases are synthesized in response to environmental stress, including phosphate starvation (Bariola et al 1999;Ma and Oliveira 2000;Kock et al 2006).…”

“…Acid RNases PD2 (from almond tree) and RSH1 (from barley) of the mass 25 kDa have been classified as belonging to this group of enzymes (Ma and Oliveira 2000;Gausing 2000). Results of numerous studies confirm that S-like RNases are synthesized in response to environmental stress, including phosphate starvation (Bariola et al 1999;Ma and Oliveira 2000;Kock et al 2006). In response to a decreased concentration of P i in a cell, class I RNases, which are for instance responsible for the release of P i during RNA degradation, are accumulated in the vacuole (Chen et al 2000).…”

Evidence for rare recombination at the gametophytic self-incompatibility locus

“…All S-allele genomic sequences so far obtained from species of Solanaceae (N ¼ 14), Rosaceae (N ¼ 18) and Scrophulariaceae (N ¼ 36) have one intron in the HVa region, and in the genomic sequences from Scrophulariaceae the intron lengths vary (Vieira and Charlesworth, 2002). Five of the 18 genomic S-allele sequences from Rosaceae have a second intron at the cleavage site between the signal peptide and the C1 region (Ma and Oliveira, 2000). In Rosaceae and Scrophulariaceae, the distances between pairs of polymorphic sites that are separated by introns therefore differ between different pairs of alleles in a species.…”