BIL9 Promotes Both Plant Growth via BR Signaling and Drought Stress Resistance by Binding with the Transcription Factor HDG11.

Drought stress is a major threat leading to global plant and crop losses in the context of the climate change crisis. Brassinosteroids (BRs) are plant steroid hormones, and the BR signaling mechanism in plant development has been well elucidated. Nevertheless, the specific mechanisms of BR signaling in drought stress are still unclear.

Peptide Epimerase Responsible for d-Amino Acid Introduction in Poly-γ-glutamic Acid Biosynthesis.

Poly-γ-glutamic acid (PGA) is a natural polymer of d- and/or l-glutamic acid (Glu) linked by isopeptide bonds. We recently showed that PGA synthetase, an enzyme complex composed of PgsB, PgsC, and PgsA, uses only l-Glu for polymerization, and d-Glu residues are introduced by peptide epimerization. However, it remains unclear which of the three enzymes is responsible for epimerization because in vitro functional characterization of the membrane-associated PgsBCA complex has never been successful.

BRZ-INSENSITIVE-PALE GREEN 1 is encoded by chlorophyll biosynthesis enzyme gene that functions in the downstream of brassinosteroid signaling.

Brassinosteroids (BRs), a kind of phytohormone, have various biological activities such as promoting plant growth, increasing stress resistance, and chloroplast development. Though BRs have been known to have physiological effects on chloroplast, the detailed mechanism of chloroplast development and chlorophyll biosynthesis in BR signaling remains unknown. Here we identified a recessive pale green Arabidopsis mutant, Brz-insensitive-pale green1 (bpg1), which was insensitive to promoting of greening by BR biosynthesis-specific inhibitor Brz in the light.