title: AhSL28, a senescence- and phosphate starvation-induced S-like RNase gene in Antirrhinum.
abstract: Several species of higher plants have been found to contain S-like ribonucleases (RNases), which are homologous to S-RNases controlling self-incompatibility. No S-like RNase genes have been isolated from self-incompatible Antirrhinum. To investigate the relationship between S- and S-like RNases, we cloned a gene named AhSL28 encoding an S-like RNase in Antirrhinum. Amino acid sequence, genomic structure and phylogenetic analyses indicated that AhSL28 is most similar to RNS2, an S-like RNase from Arabidopsis thaliana and formed a distinct subclass together with several other S-like RNases within the S-RNase superfamily. Unlike S-RNase genes in Antirrhinum, AhSL28 is not only expressed in pistils but also in leaves, petals, sepals and anthers, in particular, showing a strong expression in vascular tissues and transmitting track. Moreover, its RNA transcripts were induced during leaf senescence and phosphate (Pi) starvation but not by wounding, indicating that AhSL28 plays a role in remobilizing Pi and other nutrients, particularly when cells senesce and are under limited Pi conditions in Antirrhinum. Possible evolutionary relations of S- and S-like RNases as well as signal transduction pathways related to S-like RNase action are discussed.
authors.affiliation: Institute of Genetics and Developmental Biology, The Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Lizhi
authors.initials: L
authors.lastname: Liang
authors.forename: Zhao
authors.initials: Z
authors.lastname: Lai
authors.forename: Wenshi
authors.initials: W
authors.lastname: Ma
authors.forename: Yansheng
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yongbiao
authors.initials: Y
authors.lastname: Xue
mesh_terms: D000595:Amino Acid Sequence; D032161:Antirrhinum / Q000235:genetics*; D029681:Arabidopsis Proteins; D003001:Cloning, Molecular; D008969:Molecular Sequence Data; D010710:Phosphates / Q000172:deficiency; D010802:Phylogeny; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins; D012260:Ribonucleases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D016415:Sequence Alignment; D013997:Time Factors
chemical_list: D029681:Arabidopsis Proteins; D010710:Phosphates; D010940:Plant Proteins; C489907:RNS2 protein, Arabidopsis; D012260:Ribonucleases; C489908:S-like RNase protein, plant