Plant Molecular Biology

, Volume 36, Issue 3, pp 439–449 | Cite as

Senescence-induced RNases in tomato

  • Amnon Lers
  • Andrei Khalchitski
  • Ella Lomaniec
  • Shaul Burd
  • Pamela J. Green


A main feature of leaf senescence is the hydrolysis of macromolecules by hydrolases of various types, and redistribution of released materials. We have initiated a study for the characterization of RNases involved in nucleic acid catabolism during senescence. Using a PCR-based cloning approach we isolated from tomato two senescence-induced RNase cDNA clones. Each of these cDNAs hybridized to a senescence-induced transcript in northern analysis. One RNase cDNA was identical to the tomato LX RNase while the second corresponded to the LE RNase. Both LX and LE RNase genes had originally been demonstrated to be induced after phosphate starvation of tomato cell culture but nothing was known about their expression or function in plants. We observed that the expression of the LX and LE genes is induced in leaves during an advanced stage of senescence with the LX transcript level being much more induced than that of LE. Low-level expression of the RNase genes was observed in flowers and artificially senescing detached leaves while no expression could be detected in stems, roots, or fruits at different ripening stages. Ethylene activated the LX gene expression in detached young leaves while LE gene expression, which could be transiently induced by wounding, appeared to be activated by abscisic acid. We suggest that the LX RNase has a role in RNA catabolism in the final stage of senescence, and LE may function during wounding as a plant defense protein.

ethylene gene expression leaf senescence RNase tomato wounding 


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  1. 1.
    Abel S, Glund K: Localization of RNA-degrading enzyme activity within vacuoles of cultured tomato cells. Physiol Plant 66: 79–86 (1986).Google Scholar
  2. 2.
    Abel S, Glund K: Ribonuclease in plant vacuoles: purification and molecular properties of the enzyme from cultured tomato cells. Planta 172: 71–78 (1987).Google Scholar
  3. 3.
    Aharoni N: Interrelationship between ethylene and growth regulators in senescence of lettuce leaf disks. J Plant Growth Reg 8: 309–317 (1989).Google Scholar
  4. 4.
    Aharoni N, Lieberman M: Ethylene as regulator of senescence in tobacco leaf disks. Plant Physiol 64: 801–804 (1979).Google Scholar
  5. 5.
    Bariola PA, Green PJ: Plant Ribonucleases. In: D'alessio G, Riordan JF (eds) Ribonucleases: Structure and Function, Academic Press, Orlando, in press.Google Scholar
  6. 6.
    Bariola PA, Howard CJ, Taylor CB, Verburg MT, Jaglan VD, Green PJ: The Arabidopsis ribonuclease gene RNS1 is tightly controlled in responce to phosphate limitation. Plant J 6: 673–685 (1994).PubMedGoogle Scholar
  7. 7.
    Barry CS, Blume B, Bouzayen M, Cooper W, Hamilton AJ, Grierson D: Differential expression of the 1-aminocyclopropane-1-carboxylate oxidase gene family of tomato. Plant J 9: 525–535 (1996).CrossRefPubMedGoogle Scholar
  8. 8.
    Baumgartner B, Kende H, Matile P: Ribonuclease in senescing morning glory. Plant Physiol 55: 734–737 (1975).Google Scholar
  9. 9.
    Blank A, McKeon TA: Single-strand-preferring nuclease activity in wheat leaves is increased in senescence and is negatively photoregulated. Proc Natl Acad Sci USA 86: 3169–3173 (1989).Google Scholar
  10. 10.
    Blank A, McKeon TA: Expression of three RNase activities during natural and dark-induced senescence of wheat leaves. Plant Physiol 97: 1409–1413 (1991).Google Scholar
  11. 11.
    Farkas GL: Ribonucleases and ribonucleic acid breakdown. Encycl Plant Physiol New Ser 14B: 224–262 (1982).Google Scholar
  12. 12.
    Feinberg AP, Vogelstein B: Atechnique for radiolabeling DNA restriction endonuclease fragments to high specific activity. Anal Biochem 137: 266 (1983).Google Scholar
  13. 13.
    Feller U, Fischer A: Nitrogen metabolism in senescing leaves. Crit Rev Plant Sci 13: 241–273 (1994)Google Scholar
  14. 14.
    Gepstein S, Thimann KV: The role of ethylene in the senescence of oat leaves. Plant Physiol 68: 349–354 (1981).Google Scholar
  15. 15.
    Gepstein S: Photosynthesis. In: Nooden LD, Leopold AC (eds), Senescence andAging in Plants, pp. 147–179, Academic Press, San Diego (1988).Google Scholar
  16. 16.
    Green PJ: The ribonucleases of higher plants. Annu Rev Plant Physiol Plant Mol Biol 45: 421–445 (1994).CrossRefGoogle Scholar
  17. 17.
    John I, Drake R, Farrell A, Cooper W, Lee P, Horton P, Grierson D: Delayed leaf senescence in ethylene-deficient ACC-oxidase antisense tomato plants: molecular and physiological analysis. Plant J 7: 483–490 (1995).Google Scholar
  18. 18.
    Jost W, Bak H, Glund K, Terpstra P, Beintema JJ: Amino acid sequence of an extracellular, phosphate-starvation-induced ribonuclease from cultured tomato (Lycopersicon esculentum) cells. Eur J Biochem 198: 1–6 (1991).PubMedGoogle Scholar
  19. 19.
    Kiss T, Kis M, Solymosy F: Nucleotide sequence of a 25S rRNA gene from tomato. Nuc Acids Res 17: 796 (1989).Google Scholar
  20. 20.
    Köck M, Löffler A, Abel S, Glund K: cDNA structure and regulatory properties of a family of starvation-induced ribonucleases from tomato. Plant Mol Biol 27: 477–485 (1995).PubMedGoogle Scholar
  21. 21.
    Löffler A, Abel S, Jost W, Beintema JJ, Glund K: Phosphateregulated induction of intracellular ribonucleases in cultured tomato (Lycopersicon esculentum) cells. Plant Physiol 98: 1472–1478 (1992).Google Scholar
  22. 22.
    Matile P: Chloroplast senescence. In: Baker NR, Thomas H (eds) Crop photosynthesis: Spatial and Temporal Determinants, pp. 413–419, Elsevier, Amsterdam (1992).Google Scholar
  23. 23.
    McHale JS, Dove LD: Ribonuclease activity in tomato leaves as related to development and senescence. New Phytol 67: 505–515 (1968).Google Scholar
  24. 24.
    McKeon TA, Lyman ML, Prestamo G: Purification and characterization of two ribonucleases from developing tomato fruit. Arch Biochem Biophys 290: 303–311 (1991).PubMedGoogle Scholar
  25. 25.
    Meir S, Philosoph-Hadas S, Aharoni N: Ethylene-increased accumulation of fluorescent lipid-peroxidation products detected during senescence of parsley by a newly developed method. J Am Soc Hort Sci 117: 128–132 (1992).Google Scholar
  26. 26.
    Newman TC, Ohme-Takagi m, Taylor CB, Green PJ: DST sequences, highly conserved among plant SAUR genes, target reporter transcripts for rapid degradation in tobacco. Plant Cell 5: 701–714 (1993).CrossRefPubMedGoogle Scholar
  27. 27.
    Nürnberger T, Abel S, Jost W, Glund K: Induction of an extracellular ribonuclease in cultured tomato cells upon phosphate starvation. Plant Physiol 92: 970–976 (1990).Google Scholar
  28. 28.
    Peoples MB, Dalling MJ: The interplay between proteolysis and amino acid metabolism during senescence and nitrogen realocation. In: Nooden LD, Leopold AC (eds) Senescence and Aging in Plants, pp. 181–217. Academic Press, San Diego (1988).Google Scholar
  29. 29.
    Porra RJ, Thompson WA, Kriedemann PE: Determination of accurate extinction coefficients and simultaneous equations for assaying chlorophylls a and b extracted with four different solvents: verification of the concentration of chlorophyll standards by atomic absorption spectroscopy. Biochim Biophys Acta 975: 384–394 (1989).Google Scholar
  30. 30.
    Puissant C, Houdebine L-M: An improvement of the single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. BioTechniques 8: 148–149 (1990).PubMedGoogle Scholar
  31. 31.
    Rogers SO, Bendich AJ: Extraction of DNA from plant tissues. In: Gelvin SB, Schilperoort RA, Verma DPS (eds) Plant Molecular Biology Manual, pp. A6/1–A6/10. Kluwer Academic Publishers, Dordrecht (1990).Google Scholar
  32. 32.
    Sambrook J, Fritsch EF, Maniatis T: Molecular Cloning: A Laboratory Manual, 2nd ed. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY (1989).Google Scholar
  33. 33.
    Sanger F, Nicklen S, Coulsen: DNA sequencing with chainterminating inhibitors. Proc Natl Acad Sci USA 74: 5463–5467 (1977).PubMedGoogle Scholar
  34. 34.
    Taylor CB, Bariola PA, DelCardayré SB, Raines RT, Green PJ: RNS2: senescence-associated RNase of Arabidopsis that diverged from the S-RNases before speciation. Proc Natl Acad Sci USA 90: 5118–5122 (1993).PubMedGoogle Scholar
  35. 35.
    Taylor CB, Green PJ: Genes with homology to fungal and S-gene RNases are expressed in Arabidopsis thaliana. Plant Physiol 96: 980–984 (1991).Google Scholar
  36. 36.
    Yemm EW, Cocking EC: The determination of amino acids with ninhydrin. Analyst 80: 209–213 (1954).Google Scholar

Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  • Amnon Lers
    • 1
  • Andrei Khalchitski
    • 1
  • Ella Lomaniec
    • 1
  • Shaul Burd
    • 1
  • Pamela J. Green
    • 2
  1. 1.Department of Postharvest Science of Fresh ProduceThe Volcani CenterBet DaganIsrael
  2. 2.MSU-DOE Plant Research LaboratoryMichigan State UniversityEast LansingUSA

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