Designing a synthetic moss genome using GenoDesigner.

The de novo synthesis of genomes has made unprecedented progress and achieved milestones, particularly in bacteria and yeast. However, the process of synthesizing a multicellular plant genome has not progressed at the same pace, due to the complexity of multicellular plant genomes, technical difficulties associated with large genome size and structure, and the intricacies of gene regulation and expression in plants. Here we outline the bottom-up design principles for the de novo synthesis of the Physcomitrium patens (that is, earthmoss) genome.

Brassinosteroid regulates stomatal development in etiolated Arabidopsis cotyledons via transcription factors BZR1 and BES1.

Brassinosteroids (BRs) are phytohormones that regulate stomatal development. In this study, we report that BR represses stomatal development in etiolated Arabidopsis (Arabidopsis thaliana) cotyledons via transcription factors BRASSINAZOLE RESISTANT 1 (BZR1) and bri1-EMS SUPPRESSOR1 (BES1), which directly target MITOGEN-ACTIVATED PROTEIN KINASE KINASE 9 (MKK9) and FAMA, 2 important genes for stomatal development. BZR1/BES1 bind MKK9 and FAMA promoters in vitro and in vivo, and mutation of the BZR1/BES1 binding motif in MKK9/FAMA promoters abolishes their transcription regulation by BZR1/BES1 in plants.

A designer synthetic chromosome fragment functions in moss.

Rapid advances in DNA synthesis techniques have enabled the assembly and engineering of viral and microbial genomes, presenting new opportunities for synthetic genomics in multicellular eukaryotic organisms. These organisms, characterized by larger genomes, abundant transposons and extensive epigenetic regulation, pose unique challenges. Here we report the in vivo assembly of chromosomal fragments in the moss Physcomitrium patens, producing phenotypically virtually wild-type lines in which one-third of the coding region of a chromosomal arm is replaced by redesigned, chemically synthesized fragments.

Brassinosteroid and Hydrogen Peroxide Interdependently Induce Stomatal Opening by Promoting Guard Cell Starch Degradation.

Starch is the major storage carbohydrate in plants and functions in buffering carbon and energy availability for plant fitness with challenging environmental conditions. The timing and extent of starch degradation appear to be determined by diverse hormonal and environmental signals; however, our understanding of the regulation of starch metabolism is fragmentary. Here, we demonstrate that the phytohormone brassinosteroid (BR) and redox signal hydrogen peroxide (HO) induce the breakdown of starch in guard cells, which promotes stomatal opening.

Brassinosteroids regulate outer ovule integument growth in part via the control of INNER NO OUTER by BRASSINOZOLE-RESISTANT family transcription factors.

Brassinosteroids (BRs) play important roles in regulating plant reproductive processes. BR signaling or BR biosynthesis null mutants do not produce seeds under natural conditions, but the molecular mechanism underlying this infertility is poorly understood. In this study, we report that outer integument growth and embryo sac development were impaired in the ovules of the Arabidopsis thaliana BR receptor null mutant bri1-116.

BZR1 Family Transcription Factors Function Redundantly and Indispensably in BR Signaling but Exhibit BRI1-Independent Function in Regulating Anther Development in Arabidopsis.

BRASSINAZOLE-RESISTANT 1 family proteins (BZRs) are central transcription factors that govern brassinosteroid (BR)-regulated gene expression and plant growth. However, it is unclear whether there exists a BZR-independent pathway that mediates BR signaling. In this study, we found that disruption of all BZRs in Arabidopsis generated a hextuple mutant (bzr-h) displaying vegetative growth phenotypes that were almost identical to those of the null mutant of three BR receptors, bri1brl1brl3 (bri-t).