Effects of aqueous root extracts and hydrophobic root exudates of cucumber (Cucumis sativus L.) on nuclei DNA content and expression of cell cycle-related genes in cucumber radicles
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Allelopathic interactions implicate the inhibition of cell division by allelochemicals. To examine the effects of autotoxic agents on cell cycle and plant growth, germinated cucumber seeds (Cucumis sativus L.) were incubated in solutions containing the aqueous root extracts of cucumber at 1:100, 1:50, 1:25 and 1:10 (w:v), or the hydrophobic root exudates of cucumber at 25, 50 and 100 mg·L−1. Aqueous root extracts and hydrophobic root exudates inhibited radicle elongation by 36.47–60.18% and 38.24–62.50%, respectively. The mitosis-specific genes were down-regulated in roots exposed to aqueous root extracts and hydrophobic root exudates. Meanwhile, exposure to either aqueous root extracts or hydrophobic root exudates decreased the proportion of 2C (C-value) and increased the proportion of 8C, leading to an increased mean C-value. We conclude that autotoxic agent-induced inhibition of radicle growth was partly attributed to the down-regulation of cell cycle-related genes and endoreduplication was enhanced under our experimental condition.
KeywordsAllelopathy Autotoxicity Cell division Cyclins CDKs Endoreduplication
This work was supported by the National Basic Research Program of China (2009CB11900), National Key Project of Scientific and Technical Supporting Programs of China (2008BADA6B02, 2006BAD07B03).
- Boudolf V, Vlieghe K, Beemster GTS, Magyar Z, Acosta JAT, Maes S, Schueren EVD, Inzé D, Veylder LD (2004) The plant-specific cyclin-dependent kinase CDKB1;1 and transcription factor E2Fa-DPa control the balance of mitotically dividing and endoreduplicating cells in Arabidopsis. Plant Cell 16:2683–2692CrossRefPubMedGoogle Scholar
- Nishida N, Tamotsu S, Nagata N, Saito C, Sakai A (2005) Allelopathic effects of volatile monoterpenoids produced by Salvia leucophylla: inhibition of cell proliferation and DNA synthesis in the root apical meristem of Brassica campestris seedlings. J Chem Ecol 31:1187–1203CrossRefPubMedGoogle Scholar
- Pines J (1995) Cyclins and cyclin-dependent kinases: a biochemical view. Biochem J 388:697–711Google Scholar
- Rice EL (1984) Allelopathy, 2nd edn. Academic, New YorkGoogle Scholar
- Uren NC (2000) Types, amounts and possible functions of compounds released into the rhizosphere by soil-grown plants. In: Pinton R, Varanini Z, Nannipieri P (eds) The rhizosphere: biochemistry and organic substances at the soil-plant interface. Marcel Dekker, Inc, New York, pp 19–40Google Scholar