The Identification Of The NO-sensitive Mutant (nob) In Arabidopsis And The First-pass Mapping Of The Genetic Locus

Nitric oxide (NO) , a bioactive molecule, is one of the earliest and most widespread signaling molecules in living organisms. In plants , NO has recently been demonstrated to be involved in the regulation of growth and development in the response to abiotic and biotic stresses and it is a key signal messenger in disease resistance in plants. More important , it has been found that NO's function in plant is similar to the traditional phytohormone , so it is forecasted to be a new type of hormone in plant.We isolate the putative NO-sensitive bushiness(nob) mutant and characterize the mutant nob by T-DNA inserted mutation and root inhibition effect of the NO donor , sodium-nitroprussiate(SNP) , in Arabidopsis thaliana. Under the influence of NO, the root of mutant is inhibited more clearly than wild type. It shows that the nob mutant is more sensitive to NO than the wild type. The reason is probably that the gene about hormone metabolism is broken out and the endogenesis hormone balance of the mutant is influenced. So obtation of the mutation can provide a effective tool to study the relation between NO and the other phytohormones. We study the relation between extraneous NO and auxin IAA leading to the adventitious root formation. The results show that both NO and IAA can promote the number of adventitious roots ,as well as inhibit the length of them , suggested the effect of NO and IAA is coherent. Furthermore , the endogenesis IAA in plant can impair the effect of NO and IAA on the adventitious root formation.In addition , genetic analysis show that the mutant is caused by single recessive gene mutation . And we position the mutation to the 5th chromosome in Arabidopsis by the map-based cloning technique.