SlZHD17 is involved in the control of chlorophyll and carotenoid metabolism in tomato fruit

Abstract

Chlorophylls and carotenoids are essential and beneficial substances for both plant and human health. Identifying the regulatory network of these pigments is necessary for improving fruit quality. In a previous study, we identified an R2R3-MYB transcription factor, SlMYB72, that plays an important role in chlorophyll and carotenoid metabolism in tomato fruit. Here, we demonstrated that the SlMYB72-interacting protein SlZHD17, which belongs to the zinc-finger homeodomain transcription factor family, also functions in chlorophyll and carotenoid metabolism. Silencing SlZHD17 in tomato improved multiple beneficial agronomic traits, including dwarfism, accelerated flowering, and earlier fruit harvest. More importantly, downregulating SlZHD17 in fruits resulted in larger chloroplasts and a higher chlorophyll content. Dual-luciferase, yeast one-hybrid and electrophoretic mobility shift assays clarified that SlZHD17 regulates the chlorophyll biosynthesis gene SlPOR-B and chloroplast developmental regulator SlTKN2 in a direct manner. Chlorophyll degradation and plastid transformation were also retarded after suppression of SlZHD17 in fruits, which was caused by the inhibition of SlSGR1, a crucial factor in chlorophyll degradation. On the other hand, the expression of the carotenoid biosynthesis genes SlPSY1 and SlZISO was also suppressed and directly regulated by SlZHD17, which induced uneven pigmentation and decreased the lycopene content in fruits with SlZHD17 suppression at the ripe stage. Furthermore, the protein–protein interactions between SlZHD17 and other pigment regulators, including SlARF4, SlBEL11, and SlTAGL1, were also presented. This study provides new insight into the complex pigment regulatory network and provides new options for breeding strategies aiming to improve fruit quality.

Identification of Interacting Proteins of Transcription Factor DpAP2 Related to Carotenoid Biosynthesis From Marine Microalga Dunaliella parva

“…The current studies focused on the regulators (especially transcription factors) of the metabolic pathway rather than the key enzyme (Li et al, 2021). A lot of transcription factors (TFs) regulating the carotenoid biosynthesis pathway were identified in higher plants, which included MADS-box (Kang et al, 2021), NAC (Gong et al, 2021), AP2/ERF (Dang et al, 2021), and MYB families (Shi et al, 2021). These TFs can bind to the promoter of the target gene.…”

Transcriptomics Integrated with Metabolomics Unveil Carotenoids Accumulation and Correlated Gene Regulation in White and Yellow-Fleshed Turnip (Brassica rapa ssp. rapa)

“…Based on carotenoid metabolism in tomato fruit, Wu et al [ 28 ] and Shi et al [ 29 ] identified an R2R3-MYB transcription factor, SlMYB72 , and demonstrated that the SlMYB72-interacting protein SlZHD17, which belongs to the zinc-finger homeodomain transcription factor family, also functions in carotenoid metabolism. They also found that the expressions of PSY1 and Z-ISO were suppressed due to the regulation by SlZHD17 , which decreased the lycopene content in fruits.…”

“…Wu et al [ 28 ] reported that SlMYB72 , a R2R3-MYB subfamily, directly bound to phytoene synthase, z-carotene isomerase and lycopeneb-cyclase genes and regulated carotenoids biosynthesis. Shi et al [ 29 ] also published that SlZHD17 is involved in the control of chlorophyll and carotenoids metabolism in tomato fruit. To date, the carotenoid component and correlated gene analyses in white and yellow-fleshed turnip have been infrequent.…”

Regulation of a single Inositol 1-Phosphate Synthase homeolog by HSFA6B contributes to fiber yield maintenance under drought conditions in upland cotton

“…Within these 16 genes, of particular interest is the zinc-finger homeodomain containing transcription factor (TF), ZHD8 (Gohir.D04G049000), which showed a strong positive relationship with CRI under drought conditions. The ZHD family of transcription factors has been reported to regulate carotenoid biosynthesis in other systems (Shi et al, 2021). In addition, more than half of the production associated genes are related to lint yield (58%, Supplementary Table 8 ).…”

“…Using similar approaches to those performed in maize, cacao, and rice (Lei et al, 2015; Do et al, 2013; Bae et al, 2008), we identified a number of genes that exhibited strong correlations with changes in plant performance traits and metabolite abundance. Among the list of large-effect genes were orthologs of several functionally studied genes including ZHD8, BIR2, HXK1, that might be ideal candidates in cotton breeding programs (Imkampe et al, 2017; Shi et al, 2021; Dekkers et al, 2004). Additionally, we identified several co-expression modules strongly correlated with lint yield, carbon flux, and vegetative indices.…”