Studies On The Biological Effect And Molecular Polymorphism Of Rice Mutants From Spaceflight

To investigate the molecular polymorphism and the biological influence on rice induced by spaceflight,the seeds samples of two rice cultivars of Huhan 3(Hh3) and Huhan 7(Hh7) were sent to the space with two recoverable spaceships(ShenzhouⅤand ShenzhouⅥ) and took back after staying at space about 1 day and 5 days to propagate 4 generations and get some stable and valuable mutation lines.Therefore,we found a number of the new valuable mutations after spaceflight.The main results concluded as follows:1.Investigating and recording the mutants from the stable mutation lines.There could be a lot of phenotype mutants after spaceflight,including some significant changes in plant height,delayed growth period,the awn mutation,the grain size and albino or yellow leaves.After propagating 4 generations,208 stable mutants had been obtained.2.The SSR/EST-SSR,InDel and AFLP markers were used to preliminary screen the genome mutation.Some of polymorphism amplification fragments were recycled, sequenced,analyzed the difference and predicted the function with bioinformatics website and software.Also,sequence analysis of the polymorphism fragments preliminary indicated that mutation was very complex,including insertion mutation,deletion mutation, conversion mutation,transversion mutation and their combinations.Compared with deletion mutation,the relation was T＞A＞C＞G;in insertion mutation,the relation was A=G=C＞T;of conversion mutation,the relation was G/A+A/G＞T/C+C/T;and in transversion mutation,T/A accounted for 40%,G/T accounted for 60%.And the polymorphism relation was AFLP＞SSR＞InDel＞EST-SSR.Besides,most of mutation loci occurred at the 3' or 5'-end of the fragment in the simple sequence repeat fragment.3.Additionally,according to the mutant sequence,we designed the specific primers to preliminary analyze the expression difference with RT-PCR.From the seedling stage and tillering stage to heading stage,we analyzed the leave and root expression difference between mutants and wild plants with the RT-PCR technology.The results showed that the expression of 376,385,730 and 740 droped down in seedling stage.In tiliing stage, most of mutant expression had been back to normal,except for 730.In heading stage,the expression of 374,385 and 730 decreased significant.4.In addition,using near-infrared spectroscopy to measure the mutants and normal untreated seed in amylose and protein content,significant variation on morphological traits as well as the protein and amylose content were investigated.According to the experimental data,it indicated that 369,360,374,385,371,376,730,709,716,347,731, 707 and 708 showed significant difference in amylose or protein content compared with the normal plant seeds.5.To analyze the drought-tolerance of Hh3 and Hh7 mutants,we used the drought-resistant field base of Shanghai Agrobiological Gene Center(SAGC).We selected the drought tolerant or sensitive materials from 101 mutant lines.Ten drought tolerant and sensitive materials had been selected respectively.Also,with AFLP markers we screened some drought-sensitive lines,including 349,371,376 and 392.Therefore, we could confirm the biological response to drought stress condition after spaceflight.The experimental results preliminary showed that the spaceflight factors could induce DNA sequence variation of rice seeds.Through selecting several generations of cultivation,we had obtained stable mutant lines to preliminary screen with molecular markers,analyze with RT-PCR,measure amylose and protein content,and preliminary identify rice drought tolerance,which could be used as space mutation of rice germplasm innovation and varieties selection.