ERECTA receptor-like kinase and heterotrimeric G protein from Arabidopsis are required for resistance to the necrotrophic fungus Plectosphaerella cucumerina

作者：Llorente F; Alonso Blanco C; Sanchez Rodriguez C; Jorda L; Molina A^*

来源：Plant Journal, 2005, 43(2): 165-180.

DOI：10.1111/j.1365-313X.2005.02440.x

• ERECTA
• heterotrimeric G protein
• plant defense
• natural variability
• necrotrophic fungi
• receptor-like kinase

Arabidopsis resistance to the necrotrophic fungus Plectosphaerella cucumerina is complex and depends on the ethylene, jasmonic acid and salicylic acid signaling pathways. A quantitative trait loci (QTL) analysis of resistance to this fungus was performed using two populations of recombinant inbred lines. Three loci ORP1-QRP3 (for Quantitative Resistance to Plectosphaerella) were identified and mapped on chromosome 2 (QRP1 and QRP2) and 5 (ORP3). QRP1, the locus showing the strongest effect, was found to correspond to the ERECTA (ER) gene that encodes a receptor-like-kinase (RLK), which has been previously implicated in plant development, and resistance to the bacterium Ralstonia, solanacearum. The leucine-rich repeat and the kinase domains of ERECTA were specifically required for resistance to A cucumerina, as er mutant alleles impaired in any of these domains showed enhanced susceptibility to this fungus, but not to other virulent pathogens. The involvement of the ER-signaling pathway in resistance to P. cucumerina was supported by the fact that three mutants defective in this pathway, elk2, elk5 and elk4 (agb 1-1), which encodes the P-subunit of Arabidopsis heterotrimeric G protein, were also impaired in their resistance to this fungus. The putative function of the Arabidopsis heterotrimeric G protein in resistance to P. cucumerina suggested by the enhanced susceptibility of agb1-1 was corroborated by the demonstration that a null allele (gpa1-4) of the G protein alpha-subunit showed enhanced resistance to this pathogen. Deposition of beta-1,3-glucan callose at infection sites was specifically impaired in er-1 and agb1-1 mutants upon P. cucumerina inoculation. Taken together, these data suggest a putative function of ERECTA and heterotrimeric G protein in P. cucumerina perception.

• 出版日期2005-7