Preliminary Analysis of Functional Diversity of RALF Peptide Family in Arabidopsis thaliana

doi:10.13560/j.cnki.biotech.bull.1985.2018-0921

Abstract

Abstract: The Rapid Alkalinization Factor（RALF）,which exists as a gene family,is a kind of conservative peptide molecule in green plant. There are at least 35 RALF genes in model plant Arabidopsis thaliana. Previous studies show that certain members of RALF family,such as RALF1/23 and RALF4/19 function as the ligand of CrRLK1L members FERONIA and BUPS1/2 respectively,thus regulate cell elongation,plant immune response and double fertilization. However,whether other RALF members have biological activity and whether distinct RALF have varied functions are still unclear. Here,we have expressed 19 heterogeneous representative RALFs and analyzed their biological activities and functional diversity. The experimental results showed that all 19 RALF proteins inhibited root growth at various extents. Some representative RALF members were further selected for flg22-induced ROS release and MAPK phosphorylation level assays. From the results,we confirmed that 11 RALF proteins participated in the response of MAPK signal,and also confirmed that 16 RALF proteins inhibited the ROS release caused by flg22. In addition,there were significant differences in the regulation of hypocotyl elongation,for instance,RALF10 promoted hypocotyl elongation. The above results suggest that different RALF have both functional redundancy and differences. This study complements and improves the understanding of the complexity and diversity of RALF functions.

Key words: Arabidopsis thaliana, root length, hypocotyl, plant immunity, RALF10

QIANG Xiao-nan, LI Xin, CHEN Jia, LIAO Hong-dong, YU Feng. Preliminary Analysis of Functional Diversity of RALF Peptide Family in Arabidopsis thaliana[J]. Biotechnology Bulletin, 2019, 35(1): 2-10.

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