Open AccessBarley guanine nucleotide exchange factor Hv GEF14 is an activator of the susceptibility factor Hv RACB and supports host cell entry by Blumeria graminis f. sp. hordei
Author(s) -
Trutzenberg Adriana,
Engelhardt Stefan,
Weiß Lukas,
Hückelhoven Ralph
Publication year - 2022
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.13246
Subject(s) - guanine nucleotide exchange factor , blumeria graminis , biology , gtpase , microbiology and biotechnology , hordeum vulgare , effector , genetics , botany , gene , plant disease resistance , poaceae
In barley ( Hordeum vulgare ), signalling rat sarcoma homolog (RHO) of plants guanosine triphosphate hydrolases (ROP GTPases) support the penetration success of Blumeria graminis f. sp. hordei but little is known about ROP activation. Guanine nucleotide exchange factors (GEFs) facilitate the exchange of ROP‐bound GDP for GTP and thereby turn ROPs into a signalling‐activated ROP‐GTP state. Plants possess a unique class of GEFs harbouring a plant‐specific ROP nucleotide exchanger domain (PRONE). Here, we performed phylogenetic analyses and annotated barley PRONE‐GEFs. The leaf epidermal‐expressed PRONE‐GEF HvGEF14 undergoes a transcriptional down‐regulation on inoculation with B. graminis f. sp. hordei and directly interacts with the ROP GTPase and susceptibility factor Hv RACB in yeast and in planta. Overexpression of activated Hv RACB or of Hv GEF14 led to the recruitment of ROP downstream interactor Hv RIC171 to the cell periphery. Hv GEF14 further supported direct interaction of Hv RACB with a Hv RACB‐GTP‐binding CRIB (Cdc42/Rac Interactive Binding motif) domain‐containing Hv RIC171 truncation. Finally, the overexpression of HvGEF14 caused enhanced susceptibility to fungal entry, while HvGEF14 RNAi provoked a trend to more penetration resistance. Hv GEF14 might therefore play a role in the activation of Hv RACB in barley epidermal cells during fungal penetration.