| The space environment is characterized by low temperature,strong radiation,and microgravity.It plays an important role in studying the spatial adaptation and mutation of organisms and mutation breeding.A large number of flight tests have shown that the space environment will have different degrees of influence on the phenotype,growth state,metabolic processes,and gene protein expression of various organisms.Oryza sativa is a gramineous plant,and it has gradually become a typical model plant because of its relatively small genome,few introns,high gene density,and short growth cycle.In order to explore the effects of space carrying on photosynthesis of plants and further explore the molecular mechanisms of biological effects,Our subject put the seeds of oryza sativa Dongnong 423(DN423)and Dongnong 416(DN416)on the Space Program SJ-10 recoverable satellite,and took a combination of photosynthetic physiological characteristics,gene expression and proteomic change to examine the response of rice satellite.The photosynthetic change pattern of oryza sativa was studied in multiple layer and obtained the following results:1.The change of photosynthetic efficiency of the two rices varieties after spaceflight was comprehensive analyzed by some physiological characteristics.The gas exchange parameters,such as net photosynthetic rate,stomatal conductance,and internal carbon dioxide concentration,were measured during the tillage stage,and combined with the chlorophyll content and chlorophyll fluorescence parameters.The photosynthetic capacity of oryza sativa Dongnong 423 was found to be higher than that of the ground control,and the photosynthetic efficiency of Dongnong 416 was inhibited,suggesting that the spatial environment promoted and inhibited the photosynthesis of the two rice varieties respectively.2.The i TRAQ technology was used to detect the protein expression levels of two rices at the trefoil stage and tillering stage,and the photosynthetic differential proteins were further analyzed by some bioinformatics methods such as GO analysis,KEGG pathway analysis and String Network.We found there were three photosynthetic differential proteins in oryza sativa DN423 at trefoil compared with control groups,of which 2 were up-regulated and 1 was down-regulated.During the tillering stage,there were 5 differential proteins,3 were up-regulated,and 2 were down-regulated.As for oryza sativa DN416,There were 3 down-regulated proteins in trefoil stage and 11 proteins were down-regulated during the tillering stage.After the spaceflight,some photosynthetic proteins were changed in the two kind rices,but the change trends and number were different,and the same condition was that the number of photosynthetic differential proteins was increased gradually with rice growth.3.Quantitative RT-PCR was used to validate the partial differential proteins of two rices.At the same time,we analyzed the gene expression levels of the key proteins in the photosynthetic pathway whose protein expression did not change.We found that spaceflight had a promoting effect on photosynthetic genes expression of DN423 and inhibited photosynthetic gene expression in oryza sativa DN416.There was not a consistent relationship between protein expression and gene expressionin the two rice cultivars.Some of the genes were changed at the transcriptional level and there was no significant difference in protein expression,indicating that spatial loading has more influence on genes than on proteins.4.Spaceflight can promote the photosynthesis capacity of oryza sativa DN423 in genes,proteins and physiological performance,and had a significant effect in the rice tillering stage.While space environment reduced DN416 photosynthesis capacity from gene level to physiological manifestations in the trefoil and tillering stages.It indicated that the change of photosynthetic efficiency of different rice genotypes can be different though they were loaded in the same saiellite. |
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