The Role Of Actin Depolymerizing Factor AtADF1 In The Development Of Cotylendon In Arabidopsis

Leaf is an important organ of plant,it is the main tissue of photosynthesis which involves in energy transfer and the synthesis of organics.Leaf development is determined by the morphogenesis of epidermal cells.The epidermal cells in Arabidopsis are interlocking jigsaw puzzle-shaped pavement cells which serve as an exciting model to investigate the mechanisms for cell shape formation.Studies have shown that the microfilament is involved in the morphogenesis of pavement cell regulated by ROP2/RIC4 pathway,however,the mechanism of actin in the morphogenesis of pavement cell is still unclear.According to previous studies,the expression level of Arabidopsis microfilament depolymerization factor AtADF1 is higher in leaves than in other tissues,and the leaf area of AtADF1 RNAi plants is increased,suggesting that AtADF1 may play important roles in leaf development,however the mechanism is still unknown.In this paper,the role of AtADF1 in the development of Arabidopsis cotyledon was studied.In this study,the complementation lines of AtADF1 were obtained by vector construction and resistance screening,and Arabidopsis wild type(WT),AtADF1 mutants(Atadf1-1,Atadf1-2),AtADF1-COM and overexpression lines(AtADF1-OE#33 and AtADF1-OE#75)were selected(collectively referred to as AtADF1 materials).In addition,as microfilament-binding protein,the role of AtADF1 in the regulation of organization and dynamics of actin is closely related to its function.The leaf area and length-width ratio of wild-type(WT)and AtADF1 materials were observed and the data were analyzed.The pavement cell area,roundness,Lobe number,and average Lobe length were analyzed in WT and AtADF1 materials growth on 1/2MS for 3 d,5 d and 7 d.The organizations of actin in the pavement cells of WT and Atadf1-2 were observed.The results were as follows:(1)The homozygous Atadf1-1 mutant line was obtained by mutant identification and screening.(2)The AtADF1 complementation vector was constructed by cloning the AtADF1 promoter,and the AtAt DF1 complementation lines were obtained by screening and identification.(3)Compared with WT,the leaf area of Atadf1-1 and Atadf1-2 lines which grown on 1/2MS for 7 d were significantly increased,while the AtADF1-OE(#33,#75)showed opposite phenotypes.(4)The phenotype and statistic data results showed that compared with WT,the pavement cell area,roundness,Lobe number and Lobe length were increased in Atadf1-1 and Atadf1-2 which grown under normal conditions for 3 d,5 d,7 d.while the AtADF1-OE(#33,#75)showed opposite phenotypes.(5)The organizations of actin in the pavement cell of WT and Atadf1-2 which grown on 1/2MS for 7d were observed.The results showed that compared with WT,the density and skewness were increased in Atadf1-2 lines,suggesting that the stability of actin in Atadf1-2 lines was higher than WT.In summary,AtADF1 as an actin depolymerizing factor,play a key role in the regulation of cotyledon development by affecting the morphogenesis of pavement cell.