The Identification Of The NO-sensitive Mutant (nom) In Arabidopsis And The Mapping Of The Genetic Locus And Initial Function Analysis

Nitric oxide(NO) is one of the ten smallest chemical molecules found so far in nature and is a small highly diffusible bioactive molecule.NO has been most studied in protozoa,bacteria,yeast, human and animal.Increasing evidence indicates that NO 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.Nitric oxide research is currently an exciting field in plant biology.Many intriguing discoveries have been made recently in plants.It is clear that plant cells produce endogenous NO from animal NOS like systems,nitrate reductase-catalyzed reactions,and non-enzymatic sources.NO not only plays fundamental regulatory roles throughout the plant life cycle in concert with other phytohormones,but also functions as a signaling molecule, mediating plant responses to abiotic and biotic stresses.These important findings have allowed scientists to propose NO as another phytohormone.Nonetheless,the study of NO in plants is just beginning,and the molecular mechanisms underlying NO signal transduction and metabolism are far from clear.Indeed,the lack of molecular and genetic information limits our understanding of its physiological function.To elucidate the function of NO,genetic mutant screens using a model plant Arabidopsis will be very powerful,as this has been a proven approach for analyzing the physiological function and dissecting signaling cascades of all other classical phytohormones.In the study,we screened for NO related mutants and found one NO-sensitive mutant nora by root inhibition effect of the NO donor (sodium-nitroprussiate SNP).Then we use map-based cloning technology clone the gene and further to analysis the function of this mutant gene.Our date show:1.Under the treatment of NO,the root of our mutant nora was inhibited more clearly than wild type.2.We found this mutant was caused by a signal recessive gene mutation.And It have a stable genetics.3.The germination and growth of this mutant is slower than wild type's.It shows that the mutant gene is probably related to the germination and growth and development of plant4.We found that our mutant nora is also sensitive to ABA, KC1,NaCl.It shows that the mutant gene may be related to the salt pathway of ABA related signaling pathways and Nitric oxide is involved in this signaling pathway through this gene.5.We identified the mutation of this mutant via the mapping-based cloning approach,and positioned the mutation of this mutant to a segment of 90kb on the 5th chromosome in Arabidopsis.It has twenty genes in this segment and It is being sequenced now.