Silencing of the phytoene desaturase (PDS) gene affects the expression of fruit-ripening genes in tomatoes

Aung Htay Naing; Swum Yi Kyu; Phyo Phyo Win Pe; Kyeung Il Park; Je Min Lee; Ki Byung Lim; Chang Kil Kim

doi:10.1186/s13007-019-0491-z

Silencing of the phytoene desaturase (PDS) gene affects the expression of fruit-ripening genes in tomatoes

Plant Methods. 2019 Oct 4:15:110. doi: 10.1186/s13007-019-0491-z. eCollection 2019.

Authors

Aung Htay Naing^#¹, Swum Yi Kyu^#¹, Phyo Phyo Win Pe², Kyeung Il Park², Je Min Lee¹, Ki Byung Lim¹, Chang Kil Kim¹

Affiliations

¹ 1Department of Horticultural Science, Kyungpook National University, Daegu, South Korea.
² 2Department of Horticulture and Life Science, Yeungnam University, Gyeongsan, South Korea.

^# Contributed equally.

Abstract

Background: Past research has shown that virus-induced phytoene desaturase (PDS) gene silencing via agroinjection in the attached and detached fruit of tomato plants results in a pale-yellow fruit phenotype. Although the PDS gene is often used as a marker for gene silencing in tomatoes, little is known about the role of PDS in fruit ripening. In this study, we investigated whether the pepper PDS gene silenced endogenous PDS genes in the fruit of two tomato cultivars, Dotaerang Plus and Legend Summer.

Results: We found that the pepper PDS gene successfully silenced endogenous PDS in tomato fruit at a silencing frequency of 100% for both cultivars. A pale-yellow silenced area was observed over virtually the entire surface of individual fruit due to the transcriptional reduction in phytoene desaturase (PDS), zeta-carotene (ZDS), prolycopene isomerase (CrtlSO), and beta-carotene hydroxylase (CrtR-b2), which are the carotenoid biosynthesis genes responsible for the red coloration in tomatoes. PDS silencing also affected the expression levels of the fruit-ripening genes Tomato AGAMOUS-LIKE1 (TAGL1), RIPENING INHIBITOR (RIN), pectin esterase gene (PE), lipoxygenase (LOX), FRUITFULL1/FRUITFUL2 (FUL1/FUL2), and the ethylene biosynthesis and response genes 1-aminocyclopropane-1-carboxylate oxidase 1 and 3 (ACO1 and ACO3) and ethylene-responsive genes (E4 and E8).

Conclusion: These results suggest that PDS is a positive regulator of ripening in tomato fruit, which must be considered when using it as a marker for virus-induced gene silencing (VIGS) experiments in order to avoid fruit-ripening side effects.

Keywords: Carotenoid biosynthesis; Ethylene biosynthesis; Fruit ripening; Relative gene expression; VIGS.