Pattern-recognition receptors (PRRs), which consist of receptor kinases (RKs) and receptor-like proteins, sense microbe- and host-derived molecular patterns associated with pathogen infection to trigger immune responses in plants. Several kinases of the 46-member Arabidopsis () receptor-like cytoplasmic kinase (RLCK) subfamily VII play important roles in pattern-triggered immunity, but it is unclear whether different RLCK VII members act specifically or redundantly in immune signaling. Here, we constructed nine higher order mutants of this subfamily (named to) and systematically characterized their immune phenotypes. The mutants , -, and - had compromised reactive oxygen species production in response to all patterns tested, indicating that the corresponding members are broadly required for the signaling of multiple PRRs. However, was defective specifically in chitin-induced reactive oxygen species production, suggesting that RCLK VII-4 members mediate the signaling of specific PRRs. Furthermore, RLCK VII-4 members were required for the chitin-triggered activation of MAPK, demonstrating that these kinases link a PRR to MAPK activation. Moreover, we found that RLCK VII-6 and -8 also were required for RK-mediated root growth. Together, these results show that numerous RLCK VII members are involved in pattern-triggered immune signaling and uncover both common and specific roles of these kinases in plant development and immunity mediated by various RKs.

Small ubiquitin-like modifier (SUMO1-3) conjugation plays a critical role in embryogenesis. Embryos deficient in the SUMO-conjugating enzyme Ubc9 die at the early postimplantation stage. ;Sumo3 +/À with Sumo3 À/À mice, and these rare mice were considerably smaller than littermates of the other genotypes. Thus, our findings suggest that expression levels and not functional differences between SUMO2 and SUMO3 are critical for normal embryogenesis.