Functional Analysis Of EARLI1 Gene In Arabidopsis Thaliana Via RNA Interference

Arabidopsis thaliana is a model plant, it belongs to Cruciferae. In recent years, Arabidopsis has been widely used in fields related to functional genomics owing to its advantages such as small genome and short life cycle, and has made a lot of research achievements. EARLI1 gene encodes a 14.7kDa protein located in cell wall, it is a member of PRP (proline-rich protein) family. EARLI1 has been documented to have multiple functions including resistance to low temperature and fungus infection. The main purpose of this study is to further study the function of EARLI1 gene with physiology, histochemistry, molecular biology or other experimental methods.Microscopic observation showed that EARLI1 is associated with the morphogenesis of leaf cells in Arabidopsis. Through the histochemistry study, EARLI1 was found to be involved in regulation of lignin synthesis in inflorescence stems. The mean value of lignin content in inflorescence stems of Col-FRI-Sf2 and RNAi Col-FRI-Sf2 plants were 9.67% and 8.76% respectively. Expression analysis of EARLI1 revealed that CCR, a key enzyme in lignin synthesis, could be affected by EARLI1.EARLI1 also can control the flowering process to a large extent in Arabidopsis. RNAi Col-FRI-Sf2 plants of EARLI1 flowered earlier than Col-FRI-Sf2 wild type plants. The average flowering time of Col-FRI-Sf2 and RNAi Col-FRI-Sf2 were 39.7 and 19.4 days, respectively. There are significant differences in main stem length, internode number and rosette leaf number between Col-FRI-Sf2 and RNAi Col-FRI-Sf2 plants. The results of RT-PCR showed that EARLI1 might delay the flowering time through the autonomous pathway by maintaining the abundance of FLC transcripts.Hydrogen peroxide was used to treat Col-FRI-Sf2 and RNAi Col-FRI-Sf2 plants. The changes in germination rate of seeds, elongation of root length and other data were analyzed statistically. The results showed that RNA interference plants is much more sensitive to hydrogen peroxide than the wild type plants. Compared to wild-type plants, the seed germination rate of RNA interference lines under 5mmol/L hydrogen peroxide concentration decreased significantly. The root length elongation of RNAi lines subjected to O.lmmol/L, 0.5mmol/L hydrogen peroxide treatment was significantly lower than wild-type plants. RNA blotting analysis showed that the expression of EARLI1 gene could be induced definitely by 100mmol/L hydrogen peroxide for different time.