Cucumber CsTRY Negatively Regulates Anthocyanin Biosynthesis and Trichome Formation When Expressed in Tobacco

Abstract

The development of trichomes (spines) on cucumber fruits is an important agronomic trait. It has been reported that two MYB family members, CsMYB6 (Csa3G824850) and CsTRY (Csa5G139610) act as negative regulators of trichome or fruit spine initiation. To further study the functions of these two genes, we overexpressed them in tobacco, and found that the flowers and seed coats of transformants overexpressing CsTRY displayed an unexpected defect in pigmentation that was not observed in plants overexpressing CsMYB6. Moreover, the expression of key genes in the flavonoid synthesis pathway was repressed in CsTRY overexpressing plants, which resulted in the decrease of several important flavonoid secondary metabolites. In addition, CsTRY could interact with the AN1 homologous gene CsAN1 (Csa7G044190) in cucumber, which further confirmed that CsTRY not only regulates the development of fruit spines, but also functions in the synthesis of flavonoids, acting as the repressor of anthocyanin synthesis.

TERMINAL FLOWER 1 and TERMINAL FLOWER 1d respond to temperature and photoperiod signals to inhibit determinate growth in cucumber

“…CsTFL1D, CsNOT2a and CsFD proteins were fused to the GAL4 activation domain (AD) or DNA‐binding domain (BD) to generate the bait constructs or prey constructs. The combination of CsTRY‐AD and CsAN1‐BD was used as the positive control (Zhang et al, 2019). (b) BiFC assay was used to verify the interaction of the protein combination in Y2H.…”

“…All constructs were confirmed by sequencing and transformed into yeast strain AH109. The yeast two hybrid assay was conducted as previously described (Zhang et al, 2019). The combination of TRY‐AD and AN1‐BD was used as a positive control.…”

Molecular Mechanisms of Plant Trichome Development

“…The MYB-type transcription factors CsMYB6 (Csa3G824850) and CsTRY (Csa5G139610) negatively regulate cucumber fruit spine initiation ( Zhang et al, 2019b ). Transformation of CsTRY ( Csa015371 ) into Arabidopsis can significantly inhibit the development of leaf trichomes.…”

Comparative Transcriptome Analysis of Hard and Tender Fruit Spines of Cucumber to Identify Genes Involved in the Morphological Development of Fruit Spines

“…According to a previous study ( Zhao et al, 2015b ), unlike Arabidopsis , cucumber has glandular and non-glandular multicellular trichomes at the same time. The non-glandular multicellular trichomes are visible throughout the aboveground part of the cucumber plant, especially on the fruit, where they are also known as fruit spines ( Zhao et al, 2015a ; Zhang et al, 2019 ; Du et al, 2020 ). Fruit spines are also an important agronomic trait that affects commercial value.…”