The effects of calmodulin on plant immunity to Pseudomonas syringae
K. LAGERSTROM (1), P. Kim (1), J. Alfano (1) (1) University of Nebraska, U.S.A.

Calmodulin (CaM) is a calcium-binding protein present in all eukaryotic cells and is essential for many cellular functions. Calcium-specific binding to CaM induces a conformational change in CaM that affects its interaction with different target proteins, influencing the activity of proteins that bind it. Through calcium signal transduction, CaM mediates a variety of important cellular processes, including the immune response. The Arabidopsis genome encodes seven CaM genes that are highly homologous and relatively uniformly expressed. The biological functions of the Arabidopsis CaMs remain largely unknown. P. syringae pv. tomato DC3000 is pathogenic on tomato and Arabidopsis. It uses a type III secretion system to inject type III effector proteins into plant cells to favor pathogenicity. A major role of type III effectors is the suppression of plant immunity. We recently found that one P. syringae effector (HopE1) utilizes CaM as a co-factor inside plant cells. Here, we show that atcam4 and atcam5 mutants were more susceptible to P. syringae. Additionally, we found more CAM1 and CAM5 gene expression after salicylic acid treatment suggesting that these CaMs may play a role in plant immunity. Our research is to investigate Arabidopsis CaMs and identify which ones play roles in plant immunity to bacterial pathogens.    

Abstract Number: P17-552
Session Type: Poster