Resistance Conferred by Antisense RNA,Polygalacturonase,Transgenic Plants,Nucleotide,mRNA,Polymerase,Nucleus

Resistance Conferred by Antisense RNA

	Resistance Conferred by Antisense RNA Antisense regulation of gene expression is a natural phenomenon concerning the specific expression of a nucleotide strand which is negative to a certain gene transcript capable of intervening the expression of that gene at different levels. Antisense RNA may bind to the loop initiated by RNA polymerase in the nucleus and interfere in the initiation of transcription.
It may function in the cytoplasm by hybridizing with mRNA leading to translation arrest by preventing the binding of ribosomes to mRNA. Antisense regulation of gene expression has been successfully exploited in plants. Some examples are inhibition of flower pigmentation by antisesnse for chalcone synthase, intervention in the expression of ribulose biphosphate carboxylase in tobacco and polygalacturonase in tomato.
Most plant viruses replicate in the cytoplasm and do not go through any nuclear phase and therefore antisense RNA may either intervene in translation or promote mRNA degradation. Antisense mediated resistance has been achieved in transgenic plants against several plant viruses including TMV. This mode of resistance appears to be milder than coat-mediated protection.