Properties and effect of NaCl-salinity on Wheat SSPnuclease activation during development tolerant and sensitive seedling

Single-strand-preferring nucleases (SSPN) (EC3.1.30.1) selectively cleave internucleotide bonds in single stranded regions of predominantly duplex DNA and DNA RNA hybrids and extensively degrade denatured DNA and RNA. The functions of singlestrand- preferring nuclease in plants are unknown. We have monitored this nuclease activity in shoots of wheat [T. aestivum (L.)] seeds were germinated in distilled water (control treatment) or in 120 mM NaCl solution (salt treatment), and SSPNs were purified from different parts of the seedlings which must be catalyzed by endonuclease(s) capable of digesting dsDNA and ssDNA. Plants have two major classes of endonucleases active towards dsDNA and ssDNA, Zn+2-dependent endonuclease and Ca+2-dependent endonuclease.