The BIRD/IDD proteins encode for C2H2 zinc finger proteins and have been shown to regulate several aspects of plant growth and interaction with the environment. In Arabidopsis thaliana, BIRD proteins have been extensively studied in the context of regulation of asymmetric cell division in the root meristem. Notably, JACKDAW (JKD) has been shown to be required for the function of the quiescent center and cell division in the ground tissue through interaction with the SCARECROW-SHORTROOT regulatory module.
Recently, we found that JKD also modulates response to pathogens. Here we study the function of the BIRD proteins in tomato. As an important vegetable, tomato (Solanum lycopersicum) is also susceptible to different pathogens, like Botrytis cinerea. In tomato cv M82, we identified the closest ortholog to the Arabidopsis JKD, SlJKD. We found that SlJKD has a similar expression domain to the Arabidopsis JKD, with a predominant expression in the cortex and endodermis. We isolated several alleles of the Sljkd and found that they display higher resistance to B. cinerea when compared to the WT plants. Metabolomics analysis of Sljkd leaves reveals differences in secondary metabolites, indicating that specific metabolites might contribute to the higher resistance against B. cinerea.
Together, we reveal a new function of JKD in modulating growth and defense in both Arabidopsis and tomato.