Characteristic And Genetic Analysis Of Common Wheat Mutant I30 With White Stripe Pattern

Plants with the absence of mechanical damage,stress and pathogen infection,showing a similar pathogen infection necrosis symptom,called lesion mimic mutations.Studies have shown that lesion mimic mutant is an ideal material for research on plant programmed cell death and disease resistance.In order to study the mechanism and genome changes of these mutants,we researched a stable inherited white spot mutant I30 obtained by chemical mutagenic,and research on its characterices and genetic analysis.The main results are as follows:1.The mutant showed white blocks and long stripes from the 3rd leaf stage and the expression of the mutant was induced by low temperature.Trypan blue staining and DAB staining showed that the mutant had programmed cell death and the accumulation of H2O2.2.Observation of the mutant chloroplasts with transmission electron microscopy indicated that chloroplast of white spot of the mutant I30 was completely degraded,and there were only few mitochondria.The chloroplast morphology of the green parts of the mutant were diversify: one part of the chloroplast was normal but its shape changed,and the structure of the thylakoid lamellar layers were disorderd;Other part of The chloroplast was changed from elliptical to circle,and the structure of the capsule layer is not clear or even degradation.3.The results showed that the chlorophyll a content,chlorophyll b content and totall chlorophyll content of the mutant were significantly lower than those of the wild type at the seedling stage,but there was no difference at the jointing stage and the heading stage.Physiological investigation demonstrated that the soluble protein content and the Proline content in the mutant were lower than those in the wild type at jointing and heading stages,while the SOD(superoxide dismutase),POD(peroxidase)and CAT(catalase)activities in the mutant were higher than those in wild type.4.It was demonstrated that there were no significant differences between mutant I30 and wild type in plant height,effective spikes per plant,spike grain number,grain yield per spike,ear length,grain yield per plant and seed setting rate,but the 1000 grain weight(TKW),flag leaf length and width of mutant were significantly lower than those of wild type.5.Genetic analysis showed that the mutant was controlled by a single recessive gene.The gene was located on the short arm of the 6D chromosome revealed by BSA + 660 K gene chip technology,located between the SSR markers Xcfd190 and 6DS-5 with the genetic distance 6.4 and 9.1cM.