Characterization and functional analysis of gerbera plant defensin(PDF)genes reveal the role of GhPDF2.4 in defense against the root rot pathogen Phytophthora cryptogea  

作　　者：Chunzhen Cheng Huan Wu Yongyan Zhang 

机构地区：[1]Shanxi Key Laboratory of Germplasm Resources Innovation and Utilization of Vegetables and Flowers,College of Horticulture,Shanxi Agricultural University,Jinzhong 030801,China [2]College of Horticulture,Fujian Agriculture and Forestry University,Fuzhou 350002,China

出　　处：《aBIOTECH》2024年第3期325-338,共14页生物技术通报（英文版）

基　　金：supported by the Construction Project for Shanxi Key Laboratory of Germplasm Resources Innovation and Utilization of Vegetables and Flowers(202204010931019);the Reward Fund for PhDs and Postdoctors of Shanxi Province(SXBYKY2022004);the Fund for High-level Talents of Shanxi Agricultural University(2021XG010).

摘　　要：Gerbera(Gerbera hybrida),a major fresh cut flower crop,is very susceptible to root rot disease.Although plant defensins(PDFs),a major group of plant antimicrobial peptides,display broad-spectrum antifungal and antibacterial activities,PDF genes in gerbera have not been systematically characterized.Here,we identified and cloned nine PDF genes from gerbera and divided them into two classes based on phylogenetic analysis.Most Class Ⅰ GhPDF genes were highly expressed in petioles,whereas all Class Ⅱ GhPDF genes were highly expressed in roots.Phytophthora cryptogea inoculation strongly upregulated all Class II GhPDF genes in roots and upregulated all Class Ⅰ GhPDF genes in petioles.Transient overexpression of GhPDF1.5 and GhPDF2.4 inhibited P.cryptogea infection in tobacco(Nicotiana benthamiana)leaves.Transient overexpression of GhPDF2.4,but not GhPDF1.5,significantly upregulated ACO and LOX gene expression in tobacco leaves,indicating that overexpressing GhPDF2.4 activated the jasmonic acid/ethylene defense pathway and that the two types of GhPDFs have different modes of action.Prokaryotically expressed recombinant GhPDF2.4 inhibited mycelial growth and delayed the hyphal swelling of P.cryptogea,in vitro,indicating that GhPDF2.4 is a morphogenetic defensin.Moreover,the addition of GhPDF2.4 to plant culture medium alleviated the root rot symptoms of in vitro-grown gerbera seedlings and greatly reduced pathogen titer in P.cryptogea-inoculated gerbera roots in the early stages of treatment.Our study provides a basis for the use of GhPDFs,especially GhPDF2.4,for controlling root rot disease in gerbera.

关 键 词：Plant defensin Root rot disease Antifungal activity 

分 类 号：Q94[生物学—植物学]