Development and prospect of transgenic herbicide-resistant cotton
Herbicides are an important tool of modern agricultural production system.According to their mechanisms,herbicides can be divided into three types.The first type is amino acid synthesis inhibitors which inhibit the key proteins or enzymes of biosynthesis in plants,e.g.glyphosate,glufosinate and imidazolinones.The second type is photosynthesis inhibitors which block-up the electronic transferring chain in plant photosynthesis,e.g.paraquat,bromine and atrazine.The third type is plant growth regulators which damage the normal growth and development of plants,e.g.2,4-D.Development of transgenic herbicide-tolerant crops has been a hotspot in recent years.A large number of genes related to herbicides-tolerance have been cloned,some of which have offered crops the phenotypic traits of tolerance to herbicides.In this paper,the often used herbicides for cotton and their mechanisms were summarized,and the applications of herbicide-resistant genes cloned in molecular breeding of cotton were listed.It was pointed out that the herbicide selection pressure caused by the use of transgenic herbicide-tolerant crops might lead to the tolerant weeds appearance.The promising prospects for the transgenic herbicide-tolerant cotton were predicted as well.