ETHYLENE ROLE IN EFFECTIVE ESTABLISHMENT OF THE PEANUT-BRADYRHIZOBIA SYMBIOTIC INTERACTION

FIGUEREDO, MARÍA SOLEDAD; REINOSO, HERMINDA; MUÑOZ, VANINA; FABRA, ADRIANA

PLANT BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2021

1435-8603

Ethylene has been implicated in nitrogen fixing symbioses in legumes whose rhizobial invasion occurs by infection threads (IT). In the symbiosis between peanut (Arachis hypogaea L.) and bradyrhizobia, bacteria penetrate the root cortex intercellularly and IT are not formed. Little attention has been paid to the function of ethylene in the establishment of this symbiosis. The aim in this article is to evaluate whether ethylene plays a role in the development of this symbiotic interaction, and the participation of Nod Factors (NF) in the regulation of ethylene signaling. ?Manipulation of ethylene in peanut was accomplished by application of 1-aminocyclopropane-1-carboxylic acid (ACC) which mimics applied ethylene, or AgNO3 which blocks ethylene responses. To elucidate the participation of NF in the regulation of ethylene signaling, we inoculated plants with a mutant isogenic bacterial strain unable to produce NF and evaluated the effect of AgNO3 on the gene expression of NF and ethylene responsive signaling pathways.?Data revealed that ethylene perception is required for the formation of nitrogen-fixing nodules, while addition of ACC does not affect peanut symbiotic performance. This phenotypic evidence was in agreement with transcriptomic data from genes involved in symbiotic and ethylene signaling pathways. NF seem to modulate the expression of ethylene signaling genes. ?Unlike legumes infected by IT formation, ACC addition to peanut does not adversely affect nodulation, but ethylene perception is required for the establishment of this symbiosis. Evidence for the contribution of NF to the modulation of ethylene-inducible defense gene expression was provided.