Biological Effects Of Atmospheric And Room Temperature Plasma Irradiation On Wheat

Mutagenesis is an effective method to create new wheat germplasm and cultivate new wheat varieties with good traits,such as insect resistance,disease resistance,lodging resistance,high yield and high quality.Atmospheric and Room Temperature Plasma（ARTP）has been successfully applied to microorganisms as a new mutagenesis pathway.In this study,four wheat varieties with different nuclear radiation sensitivity were celected:Heyou 1,Xinong 979,Zhoumai 16,Han 6172,in order to study the biological effects of ARTP on wheat（Triticum aestivum L.）.The 15-days-old immature embryo,germinating seed and dry seed of each variety were treated with ARTP of different power（200 W and400 W）and different time（0 min,10 min,20 min,30 min and 40 min）respectively,and different doses（0 Gy,5 Gy,10 Gy,15 Gy,20 Gy,25 Gy,100 Gy,150 Gy,200 Gy,250Gy）of gamma irradiation as control,to identify the phenotypic,cytological and genotypic effects of ARTP treatment on wheat.The main results are as follows:1. After ARTP andγ-ray treatment of the dry seeds of the insensitive variety Han 6172 and the sensitive variety Xinong 979,the results of seed germination experiments showed that all the treatment did not cause significant variation of seed germination,γ-ray treatment of the dry seeds can cause the variation of seedling height and root length.ARTP was used to treat the germinating seeds of insensitive variety Han 6172 and sensitive variety Xinong 979,the results of contemporary seed germination experiments show that ARTP 200 W treatment can not cause significant variation of seed germination,ARTP 400 W treatment can cause the variation of germination potential,germination rate,seedling height and root length of contemporary seeds.With the increase of treatment time,the variation is more significant,ARTP treatment can form semidwarf effect.The germination seeds treated with different doses ofγ-ray can cause the variation of germination potential,germination rate,seedling height and root length of contemporary seeds.With the increase of treatment dose,the variation is more significant,and the germination seeds treated withγ-ray can form a semi dwarf effect.2. After ARTP andγ-ray treatment of the dry seeds of the insensitive variety Han 6172 and the sensitive variety Xinong 979,the field investigation results showed that with the increase of the power and time of ARTP treatment,the agronomic characters of the plants were not significantly inhibited.With the increase of the dose afterγ-ray treatment,the agronomic characters of the plants were inhibited.But ARTP-400 W 30 min and 40min treatment can significantly reduce the number of effective spike and KGW of plants.The experimental results can not completely exclude the impact of environmental factors,which needs further verification.The field investigation results showed that the plant height,spike length,effective spike number,spike number and KGW were decreased significantly with the increase of treatment dose after the seeds were germinated byγray for insensitive varieties Han 6172 and sensitive varieties Xinong 979.The same effect trend could not be formed after the treatment of ARTP.However,some ARTP treatments can inhibit some phenotypic characters of plants.ARTP-200 W 40 min,400 W 30 min,40 min treatment can significantly reduce plant height,spike length,grain number per spike and KGW.But the experimental results can not completely exclude the impact of environmental factors,so it is uncertain that these inhibition effects must be generated by ARTP treatment,which needs further verification.3. The results of sequencing showed that both ARTP andγ-ray treatment could reduce the number of SNPs and the heterozygosity of SNPs.In the same sampling period,the ratio of SNP heterozygosity of each treatment group was higher than that of ARTP,and that of Xinong 979 was lower than that of Han 6172.ARTP treatment can cause the variation of single nucleotide of genome,but the genome damage of the sample afterγ-ray treatment is more serious.Microarray analysis showed that ARTP treatment could cause the variation of wheat genome,and it was confirmed that the mutant progeny was indeed formed by mutation of the original experimental material.The results of SLAF sequencing showed that the mutation of ARTP caused G/C base to mutate into A/T base,which decreased the content of G/C base in DNA,which was consistent in sensitive and insensitive materials.4. There was no significant difference in the recovery rate of wheat immature embryos treated with ARTP and the untreated control.Only the callus size of 200 W 40min and 400 W 30 min,40min combination was significantly smaller than that of the control group,which was consistent with the results ofγ-15 Gy,20 Gy and 25 Gy treatment.Under the same condition,the seedling rate of Han 6172 and Zhomai 16 was higher than that of Heyou1.The results of cytological observation showed that the structure of cell membrane and organelle was destroyed in the condition of 200W 40 min and 400 W 30 min,40 min after ARTP treatment,and the hungry granules were formed in the cells,and the cells were autophagic.5. In the M₂ generation of wheat treated with ARTP andγ-ray,there were mutant plants with reduced plant height,tiller number and late heading,and in the M₂ generation of wheat treated with dry seed and germinating seed,there were also mutant plants with spike shape.The mutant plants with higher plant height and lighter leaf color appeared in the M₂ population after ARTP treatment,but they did not exist in the M₂ population afterγ-ray treatment.ARTP treatment could not make M₁ Generation Plants of dry seeds form significant biological effects.After ARTP treatment of germinated seeds and calli,the seedlings of M₁ Generation of germinated seeds can form semi dwarf effect,which can cause structural variation of M₁ Generation genome of germinated seeds and calli,destroy the structure and function of cell membrane and organelle of callus,and significantly reduce the plant height,spike length,number of effective spike and number of grains per spike of M₁ Generation of germinated seeds.After the dry seeds,germinated seeds and immature embryos of wheat were treated by ARTP,the mutant plants appeared in their M₂ generation population,and the mutant characters included plant height,tiller number,spike shape,leaf color and development period.In conclusion,the application of ARTP treatment in wheat mutation is feasible.