Cucumber glossy fruit 1 (CsGLF1) encodes the zinc finger protein 6 that regulates fruit glossiness by enhancing cuticular wax biosynthesis

Cucumber glossiness is an important visual quality trait that affects consumer choice.Accumulating evidence suggests that glossy trait is associated with cuticular wax accumulation.However,the molecular genetic mechanism controlling cucumber glossiness remains largely unknown.Here,we report the map-based cloning and functional characterization of CsGLF1,a locus that determines the glossy trait in cucumber.CsGLF1 encodes a homolog of the Cys_(2)His_(2)-like fold group(C2H2)-type zinc finger protein 6(ZFP6)and its deletion leads to glossier pericarp and decreased cuticular wax accumulation.Consistently,transcriptomic analysis demonstrated that a group of wax biosynthetic genes were downregulated when CsZFP6 was absent.Further,transient expression assay revealed that CsZFP6 acted as a transcription activator of cuticular wax biosynthetic genes.Taken together,our findings demonstrated a novel regulator of fruit glossiness,which will provide new insights into regulatory mechanism of fruit glossiness in cucumber.

Brassinosteroids fine-tune secondary and primary sulfur metabolism through BZR1-mediated transcriptional regulation

For adaptation to ever-changing environments,plants have evolved elaborate metabolic systems coupled to a regulatory network for optimal growth and defense. Regulation of plant secondary metabolic pathways such as glucosinolates(GSLs) by defense phytohormones in response to different stresses and nutrient deficiency has been intensively investigated, while how growth-promoting hormone balances plant secondary and primary metabolism has been largely unexplored. Here, we found that growth-promoting hormone brassinosteroid(BR) inhibits GSLs accumulation while enhancing biosynthesis of primary sulfur metabolites, including cysteine(Cys) and glutathione(GSH) both in Arabidopsis and Brassica crops, fine-tuning secondary and primary sulfur metabolism to promote plant growth. Furthermore, we demonstrate that of BRASSINAZOLE RESISTANT 1(BZR1), the central component of BR signaling, exerts distinct transcriptional inhibition regulation on indolic and aliphatic GSL via direct MYB51 dependent repression of indolic GSL biosynthesis, while exerting partial MYB29 dependent repression of aliphatic GSL biosynthesis. Additionally, BZR1 directly activates the transcription of APR1 and APR2 which encodes rate-limiting enzyme adenosine 5′-phosphosulfate reductases in the primary sulfur metabolic pathway.In summary, our findings indicate that BR inhibits the biosynthesis of GSLs to prioritize sulfur usage for primary metabolites under normal growth conditions.These findings expand our understanding of BR promoting plant growth from a metabolism perspective.