Molecular characterisation of an S-like RNase of Nicotiana alata that is induced by phosphate starvation

Abstract

We characterised a cDNA encoding an S-like RNase (RNase NE) from the styles of the self-incompatible plant, Nicotiana alata. RNase NE is 86% identical to an extracellular RNase from tomato cell cultures, RNase LE. DNA hybridisation experiments indicate that there are ca. 5-6 sequences related to RNase NE in the N. alata genome and that RNase NE is not linked to the self-incompatibility (S) locus. RNase NE is expressed in the styles, petals and immature anthers but not in the vegetative tissues of N. alata plants under normal growth conditions. Under phosphate-limited conditions, RNase NE expression is induced in roots but not leaves of N. alata. A transcript hybridising to RNase NE is also induced in N. plumbaginifolia cell cultures in response to phosphate starvation. RNase NE is likely to play a role in the response of N. alata to phosphate limitation, possibly by scavenging phosphate from sources of RNA in the root environment. We also discuss the evolutionary relationships between the S- and S-like RNase genes in plants.

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

“…Such results are expected for the S-locus; bands are not obtained for every individual, even under low stringency conditions, because the sequences of different alleles are highly diverged (eg, Richman et al, 1996). In contrast, PCR amplification experiments and Southern blot hybridisations using sequences of specific S-like RNase loci generally detect a band in every individual, since the sequences of given loci are conserved (Dodds et al, 1996;Norioka et al, 1996;Ma and Oliveira, 2000).…”

“…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.…”

Rapid recent radiation of S-RNase lineages in Witheringia solanacea (Solanaceae)

“…To select these sequences, we sampled at random throughout the Solanaceae by obtaining S-RNase sequences submitted to GenBank before the year 2000, for species where four or more sequences were deposited (Nicotiana alata S2, S3, S6, S7; Petunia hybrida S1, S3, SB1, SB2, and Solanum chacoense S2, S3, S11, S13). Solanaceous S-like RNases LeLE and LeLX (Kock et al, 1995) and Nalata NE (Dodds et al, 1996) were used as the outgroup. ClustalX was used to align inferred amino-acid sequences, using the BLOSUM series substitution matrices, a gap origination penalty of 10 and a gap extension penalty of 0.5.…”

Upregulation of the genes for ferritin, RNase, and DnaJ in leaves of rice plants in response to sulfur deficiency

“…In some species, the expression of the genes encoding T 2 / S type RNases is induced by phosphate (Pi) starvation, suggesting that they play a role in the remobilization of Pi from RNA under Pi-deficient conditions (Loffler et al 1993;Kock et al 1995;Dodd et al 1996) large for clones with weak signals and clones with more than 2-fold variations between the duplicate spots were eliminated from further analysis. Clones whose relative signal intensity value was below IO were also eliminated because of large variations.…”