Vacuole Integrity Maintained by DUF300 Proteins Is Required for Brassinosteroid Signaling Regulation.

Brassinosteroid (BR) hormone signaling controls multiple processes during plant growth and development and is initiated at the plasma membrane through the receptor kinase BRASSINOSTEROID INSENSITIVE1 (BRI1) together with co-receptors such as BRI1-ASSOCIATED RECEPTOR KINASE1 (BAK1). BRI1 abundance is regulated by endosomal recycling and vacuolar targeting, but the role of vacuole-related proteins in BR receptor dynamics and BR responses remains elusive. Here, we show that the absence of two DUF300 domain-containing tonoplast proteins, LAZARUS1 (LAZ1) and LAZ1 HOMOLOG1 (LAZ1H1), causes vacuole morphology defects, growth inhibition, and constitutive activation of BR signaling.

Turnip Mosaic Virus Counteracts Selective Autophagy of the Viral Silencing Suppressor HCpro.

Autophagy is a conserved intracellular degradation pathway and has emerged as a key mechanism of antiviral immunity in metazoans, including the selective elimination of viral components. In turn, some animal viruses are able to escape and modulate autophagy for enhanced pathogenicity. Whether host autophagic responses and viral countermeasures play similar roles in plant-virus interactions is not well understood.

The RING-Type E3 Ligase XBAT35.2 Is Involved in Cell Death Induction and Pathogen Response.

XBAT35 belongs to a subfamily of Arabidopsis () RING-type E3s that are similar in domain architecture to the rice () XA21 Binding Protein3, a defense protein. The transcript undergoes alternative splicing to produce two protein isoforms, XBAT35.1 and XBAT35.

Autophagy as a mediator of life and death in plants.

Autophagy is a major pathway for degradation and recycling of cytoplasmic material, including individual proteins, aggregates, and entire organelles. Autophagic processes serve mainly survival functions in cellular homeostasis, stress adaptation and immune responses but can also have death-promoting activities in different eukaryotic organisms. In plants, the role of autophagy in the regulation of programmed cell death (PCD) remained elusive and a subject of debate.

Signaling unmasked: Autophagy and catalase promote programmed cell death.

Autophagy contributes to the removal of harmful cellular refuse, whereas catalase plays an important protective role by detoxifying reactive oxygen species. We recently found that autophagy and catalase are also required for promoting programmed cell death induced during plant immune responses. Here we discuss the difficulties in identifying cell death effectors, which are also required to maintain cellular homeostasis, and how their prodeath roles were unmasked using an unbiased forward genetics approach.