5257
A genetic complementation system was developed in which tobacco etch virus ( TEV ) polymerase ( NIb ) - expressing transgenic plants or protoplasts were inoculated with NIb - defective TEV mutants .
 tobacco etch virus ( TEV ) polymerase, NIb, NIb, TEV mutants
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 tobacco etch virus ( TEV ) polymerase, NIb, NIb, TEV mutants