Plant LETM1 homologs are required for fungus-induced antibiotic resistance and biostimulation

Abstract

Our findings confirm that CIRA15A / LEUCINE ZIPPER-EF-HAND CONTAINING TRANSMEMBRANE PROTEIN1 (LETM1) is critical for Trichoderma-induced growth biostimulation in sugar beet and the Cellulase-Induced Resistance to Alamethicin (CIRA) response in Arabidopsis. Notably, this plant homolog of a gene associated with human disease plays a vital role in both defense against Trichoderma antimicrobial peptides and the biostimulation of plant growth. We identified AtCIRA15A/LETM1 and AtCIRA15B/LETM2 as key genetic determinants of CIRA through Arabidopsis analysis and comparative studies of sugar beet inbred lines. BvLETM1 allelic variations correlated with differential biostimulation responses, and complementation confirmed functional LETM1 alleles restore CIRA in Arabidopsis mutants. These findings highlight LETM1 as a crucial factor in Trichoderma-plant interactions, with potential applications in breeding for enhanced microbial-induced plant biostimulation and agricultural productivity.