title: Suppression of LX ribonuclease in tomato results in a delay of leaf senescence and abscission.
abstract: Although present in different organisms and conserved in their protein sequence, the biological functions of T2 ribonucleases (RNase) are generally unknown. Tomato (Lycopersicon esculentum) LX is a T2/S-like RNase and its expression is known to be associated with phosphate starvation, ethylene responses, and senescence and programmed cell death. In this study, LX function was investigated using antisense tomato plants in which the LX protein level was reduced. LX protein levels normally become elevated when leaves senesce and antisense inhibition of LX retarded the progression of senescence. Moreover, we observed a marked delay of leaf abscission in LX-deficient plants. This correlated with specific induction of LX protein in the tomato mature abscission zone tissue. LX RNase gene regulation and the consequences of antisense inhibition indicate that LX has an important functional role in both abscission and senescence.
authors.affiliation: Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel. alers@volcani.agri.gov.il
authors.forename: Amnon
authors.initials: A
authors.lastname: Lers
authors.forename: Lilian
authors.initials: L
authors.lastname: Sonego
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Green
authors.forename: Shaul
authors.initials: S
authors.lastname: Burd
mesh_terms: D018548:Cotyledon / Q000378:metabolism; D015536:Down-Regulation; D018506:Gene Expression Regulation, Plant; D018551:Solanum lycopersicum / Q000201:enzymology* / Q000235:genetics; D018515:Plant Leaves / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D016372:RNA, Antisense; D018749:RNA, Plant; D012260:Ribonucleases / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors
chemical_list: D010940:Plant Proteins; D016372:RNA, Antisense; D018749:RNA, Plant; D012260:Ribonucleases