Silencing of the SlNAP7 gene influences plastid development and lycopene accumulation in tomato.

Hong-Liang Zhu,Lan-Huan Meng,Hua-Xue Yan,Da-Qi Fu,Ben-Zhong Zhu,Yun-Bo Luo

doi:10.1038/srep38664

Hong-Liang Zhu, Lan-Huan Meng + Show 4 more

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https://doi.org/10.1038/srep38664

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Abstract

Ripening is an important stage of fruit development. To screen the genes associated with pigment formation in tomato fruit, a suppression subtractive hybridization (SSH) cDNA library was constructed by using tomato fruit in the green ripe and break ripe stages, and 129 differential genes were obtained. Using redness as a screening marker, virus-induced gene silencing (VIGS) of the differential genes was performed with a sprout vacuum-infiltration system (SVI). The results showed that silencing the SlNAP7 gene affected the chloroplast development of tomato leaves, manifesting as a photo-bleaching phenotype, and silenced fruit significantly affected the accumulation of lycopene, manifested as a yellow phenotype. In our study, we found that silencing the SlNAP7 gene downregulates the expression of the POR and PORA genes and destroys the normal development of the chloroplast. The expression of related genes included in the lycopene biosynthesis pathway was not significantly changed, but lycopene accumulation was significantly reduced in tomato fruit. Perhaps it was caused by the destruction of the chromoplast, which leads to the oxidation of lycopene. The results show that the SlNAP7 gene influences chloroplast development and lycopene accumulation in tomato.

Highlights

Ripening is an important stage of fruit development
According to the changes in surface color during tomato fruit development, the ripening process can be divided into multiple stages, including immature (IM), mature green (MG), breaker (BR), turning (TU), and red ripening (RR)[32]
To screen some candidate genes involved in the conversion of the fruit development stage, MG-stage and BR-stage tomato fruit were selected as the driver and the tester to construct a suppression subtractive hybridization (SSH) screen because the two-stage conversion is the key color change process during fruit ripening

Summary

Introduction

Ripening is an important stage of fruit development. To screen the genes associated with pigment formation in tomato fruit, a suppression subtractive hybridization (SSH) cDNA library was constructed by using tomato fruit in the green ripe and break ripe stages, and 129 differential genes were obtained. The over-expression of APRR2-Like increases the number and size of plastids, enhancing the chlorophyll and carotenoid levels in immature and red ripe tomato fruits, respectively[15] These key genes of fruit ripening affect the development of chloroplasts, which control fruit ripening, and other cofactors may be involved in the process of fruit coloring and nutrition. We can obtain a large number of candidate genes that may be involved in the development of tomato after tomato genome sequencing, our challenge is identifying the function of a large number of candidate genes in a short time Traditional approaches such as mutant screening and plant transformation are often time consuming and labor intensive. The recombinant vector was used to infect plants to trigger the post-transcriptional gene silencing (PTGS) of the plants, resulting in the silencing of endogenous genes homologous to the inserted fragment of the virus in the plant[30,31]

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