A novel HD‐Zip I/C2H2‐ZFP/WD‐repeat complex regulates the size of spine base in cucumber

Abstract

Fruit spine is an important trait in cucumber, affecting not only commercial quality, but also fruit smoothness, transportation and storage. Spine size is determined by a multi-cellular base. However, the molecular mechanism underlying the regulation of cucumber spine base remains largely unknown. Here, we report map-based cloning and characterization of a spine base size 1 (SBS1) gene, encoding a C2H2 zinc-finger transcription factor.Near-isogenic lines of cucumber were used to map, identify and quantify cucumber spine base size 1 (CsSBS1). Yeast-hybrid, bimolecular fluorescence complementation (BiFC), coimmunoprecipitation (Co-IP) and RNA-sequencing assays were used to explore the molecular mechanism of CsSBS1 in regulating spine base size development.CsSBS1 was specifically expressed in cucumber ovaries with particularly high expression in fruit spines. Overexpression of CsSBS1 resulted in large fruit spine base, while RNAinterference silencing of CsSBS1 inhibited the expansion of fruit spine base. Sequence analysis of natural cucumber accessions revealed that CsSBS1 was lost in small spine base accessions, resulting from a 4895 bp fragment deletion in CsSBS1 locus. CsSBS1 can form a trimeric complex with two positive regulators CsTTG1 and CsGL1 to regulate spine base development through ethylene signaling.A novel regulator network is proposed that the CsGL1/CsSBS1/CsTTG1 complex plays a significant role in regulating spine base formation and size, which offers a strategy for cucumber breeders to develop smooth fruit.

NS encodes an auxin transporter that regulates the ‘numerous spines’ trait in cucumber (Cucumis sativus) fruit

“…In contrast, CsMYB6 can interact with Tu to repress initiation of spines on the tubercules (Yang et al., 2018; Zhao et al., 2020). CsSBS1, a C2H2 zinc‐finger transcription factor, interact with CsTTG1 and CsGL1 to regulate spine base development (Yang et al., 2022). However, little is known about the mechanism of type II spine formation.…”

Genome-Wide Analysis of C2H2 Zinc Finger Gene Family and Its Response to Cold and Drought Stress in Sorghum [Sorghum bicolor (L.) Moench]

“…C2H2-type zinc finger proteins are one of the most abundant transcription factor families in higher plants. Previous reports indicate that they play an important role in cucumber, Arabidopsis , wheat, and tomato [ 39 , 40 , 41 , 42 ]. Therefore, many researchers have tried to perform genome-wide analysis on C2H2-ZFP s in various species, such as tomato, wheat, grape, and oyster mushroom [ 43 , 44 , 45 , 46 ], but little is known about sorghum C2H2-ZFP proteins.…”

Morphological and Genetic Diversity of Cucumber (Cucumis sativus L.) Fruit Development

“…Notably, several of the genes implicated in trichome initiation also appear to influence subsequent trichome development. A primary determinant of spine size is size of the base, as indicated by genes such as spine size (SS) and spine base size 1 ( SBS1 ) [ 103 , 104 ]. SBS1 encodes a C2H2 zinc-finger transcription factor that was shown to form a trimeric complex with the spine density factors, CsTTG1 and CsGL1 [ 104 ].…”

“…A primary determinant of spine size is size of the base, as indicated by genes such as spine size (SS) and spine base size 1 ( SBS1 ) [ 103 , 104 ]. SBS1 encodes a C2H2 zinc-finger transcription factor that was shown to form a trimeric complex with the spine density factors, CsTTG1 and CsGL1 [ 104 ]. Overexpression of CsTTG1 also causes larger and longer spines due to an increase in both cell number and cell size [ 105 ].…”