Functional Analysis Of Arabidopsis Thaliana OGG1and Nelumbo Nucifera PER1in Seed Longevity And Abiotic Stress Tolerance

Seed longevity is an important trait to estimate seed quality, and is very importantfor the success of plant propagation, plant distribution and production. However,seeds gradually lose viability associated with ROS (reactive oxygen species)generation under normal storage conditions. Although many researches havecontributed to seed longevity, the underlying molecular and genetic mechanismremains to be further understood.OGG1protein is a bifunctional DNA glycosylase/AP lyase which excises8-oxoGand initiates the base excision repair (BER). PER1is a seeds specific gene whichbelongs to the Peroxiredoxins (Prxs) family in plant and correlates with severalstresses. There are only few studies contribute to understand the role of OGG1orPER1on seed longevity. In this study, we focus on the functions of AtOGG1andNnPER1on seed longevity and abiotic stress tolerance by transgenic Arabidopsis. Themain results are as following:1. We isolated a seed specific1-Cys Prx gene: NnPER1form sacred lotus. Usingthe QRT-PCR, we revealed that the transcript of NnPER1was highly expressed indeveloping and germinating sacred lotus seeds, and was dramatically up-regulated inresponse to NaCl and ABA. 2. The transcript of AtOGG1was detected in seeds by QRT-PCR, and it wasstrongly up-regulated during seed desiccation at the later development of seeds andimbibition at early germination.3. Both AtOGG1and NnPER1were expressed in E. coli cells, and purified toproduce specific antibodies. The purified NnPER1protein protected DNA from thecleavage of ROS in vitro.4. The Subcellular localization assays have revealed that AtOGG1was localizedin the nucleus while NnPER1distributed to the cytoplasm.5. In order to investigate the physiological functions of AtOGG1in seeds, wegenerated three transgenic Arabidopsis plants overexpressing AtOGG1.Overexpression of AtOGG1in Arabidopsis enhanced seed resistance to controlleddeterioration treatment (CDT). In addition, the content of8-oxo-dG in transgenicseeds was reduced compared to the wild-type, indicating a DNA damage repairfunction of AtOGG1in vivo. Furthermore, transgenic seeds exhibited increasedgermination ability under abiotic stresses such as methyl viologen, NaCl, mannitoland high temperatures.6. The in vivo functions of NnPER1were evaluated using the transgenicArabidopsis seeds overexpressing NnPER1. Transgenic seeds exhibited enhancedtolerance to CDT and heat stress indicating significant roles of NnPER1in seedlongevity and germination vigor. Furthermore, the transgenic seedings also displayedenhanced root elongation and growth compared to wild-type seedings under the ABAtreatment, implying a proable role of NnPER1in the response of ABA.In summary, these results demonstrated that both AtOGG1and NnPER1participating in the regulation of seed longevity and germination vigor. The resultsprovided new insight on the understanding of the mechanism of seed longevity andmay be applicable to agricultural crops for success of germplasm conservation andcrop yield.