Mitogen-activated protein kinase kinase 6 negatively regulates anthocyanin induction in Arabidopsis.

Arabidopsis mitogen-activated protein (MAP) kinase kinase 6 (MKK6) has previously been shown to play important roles in plant immunity and cytokinesis. Here we report that it is also involved in the negative regulation of anthocyanin biosynthesis in Arabidopsis. Elevated anthocyanin levels are observed in mkk6 knock out mutant plants.

MKK6 Functions in Two Parallel MAP Kinase Cascades in Immune Signaling.

Arabidopsis () MAP KINASE (MPK) proteins can function in multiple MAP kinase cascades and physiological processes. For instance, MPK4 functions in regulating development as well as in plant defense by participating in two independent MAP kinase cascades: the MEKK1-MKK1/MKK2-MPK4 cascade promotes basal resistance against pathogens and is guarded by the NB-LRR protein SUMM2, whereas the ANPs-MKK6-MPK4 cascade plays an essential role in cytokinesis. Here, we report a novel role for MKK6 in regulating plant immune responses.

Convergent and Divergent Signaling in PAMP-Triggered Immunity and Effector-Triggered Immunity.

Plants use diverse immune receptors to sense pathogen attacks. Recognition of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors localized on the plasma membrane leads to PAMP-triggered immunity (PTI). Detection of pathogen effectors by intracellular or plasma membrane-localized immune receptors results in effector-triggered immunity (ETI).

Mighty Dwarfs: Autoimmune Mutants and Their Usages in Genetic Dissection of Plant Immunity.

Plants lack the adaptive immune system possessed by mammals. Instead they rely on innate immunity to defend against pathogen attacks. Genomes of higher plants encode a large number of plant immune receptors belonging to different protein families, which are involved in the detection of pathogens and activation of downstream defense pathways.