The Map-based Cloning Of Chlorophyll Fluorescence Abnormal Mutant Cfa In Arabidopsis Thaliana

Senescence constitutes the final stages of plant growth and development.In the process of senescence,nutrients can be transported to the seed from leaves to provide adequate nutrition.Nutrient recycling process has very significant influence in plant life.Green plant chloroplast light system II contains chlorophyll that can release autofluorescence which is called chlorophyll fluorescence.Plant photosynthetic activity is related to its emission fluorescence.So we can use Chlorophyll fluorescence spectrometer to detect chlorophyll fluorescence strength so as to reflect the intensity of photosynthesis.The degradation of chlorophyll and the reduction of photosynthesis represent the beginning of senescence.Chlorophyll fluorescence could evaluate photosynthesis through the mutual transformation from the point of energy balance.The chlorophyll fluorescence images have been used to the study of plant variety.In this study,the wild type Arabidopsis(Col-0)was used as experimental material,after EMS mutagenesis,a mutant was screened by chlorophyll fluorescence equipment,which had higher Fv/Fm than wild type.The mutant appeared separation of phenotype: one was the same as the wild type,the other was a smaller mutant and its leaves curled,named it the cfa(chlorophyll fluorescence abnormal mutant,cfa).To dark the seedlings for 3 days,we used chlorophyll fluorescence spectrometer for its monitoring and found that the differences of Fv/Fm in cfa and wild type increased.In addition,the mutant cannot obtain offspring seeds normally.The results of the determination of mutant pollen germination rate and the observation of flower structure indicated that the reason of mutant sterility was the abnormal development of stamen and pistil.Then we analyzed the genetic law of mutant cfa and developed the work of map-based cloning.After the orientation of coarse and fine and guess genes work,we considered that the CFA is AT1G21700.Sequencing results showed that the 312 th of mutant genomes is the end of the first intron which changed.We have built the related vectors of the gene,and set up the vector to the wild type and mutant,and now we harvest seeds to use for follow-up study.Besides the phenotype,the difference of chlorophyll fluorescence parameters increased between wild type and the mutant after 3 days of dark treatment.During the senescence,the leaves of the mutant remained yellow but prolonged the cell death.These results suggested that the cfa may involve in the regulation of senescence.The semi-quantitative experiments of senescence related genes indicated that CFA affected the expression of senescence related gene,further identifying CFA may involve in the regulation of senescence process.