RsGLK2.1-RsNF-YA9a module positively regulates the chlorophyll biosynthesis by activating RsHEMA2 in green taproot of radish

Jiali Ying; Yan Wang; Liang Xu; Shuqi Yao; Kai Wang; Junhui Dong; Yinbo Ma; Lun Wang; Yang Xie; Kang Yan; Jingxue Li; Liwang Liu

doi:10.1016/j.plantsci.2023.111768

RsGLK2.1-RsNF-YA9a module positively regulates the chlorophyll biosynthesis by activating RsHEMA2 in green taproot of radish

Plant Sci. 2023 Sep:334:111768. doi: 10.1016/j.plantsci.2023.111768. Epub 2023 Jun 19.

Authors

Jiali Ying¹, Yan Wang¹, Liang Xu¹, Shuqi Yao¹, Kai Wang¹, Junhui Dong¹, Yinbo Ma², Lun Wang², Yang Xie¹, Kang Yan¹, Jingxue Li¹, Liwang Liu³

Affiliations

¹ National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (East China) of MOAR, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, PR China.
² College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou 225009, PR China.
³ National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (East China) of MOAR, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, PR China; College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou 225009, PR China. Electronic address: nauliulw@njau.edu.cn.

PMID: 37343602
DOI: 10.1016/j.plantsci.2023.111768

Abstract

Radish (Raphanus sativus L.) is an economically important and widely cultivated root vegetable crop. The coloration of the green skin and green flesh is an important trait influencing the nutrition and flavor quality in fruit radish. GOLDEN2-LIKEs (GLKs) play critically important roles in plastid development and chlorophyll biosynthesis in plants. However, the molecular mechanism underlying chlorophyll biosynthesis still remain elusive in green fruit radish taproot. Herein, the RsGLK2.1 gene exhibited higher expression level in taproot with a green skin (GS) and green flesh (GF) than that in taproot of the white or red radish genotypes. RsGLK2.1 is a nuclear transcription factor that has intrinsic transcriptional activation activity. Overexpression of RsGLK2.1 increased the total chlorophyll content of 20.68%-45.84% in radish leaves. Knockout of the RsGLK2.1 gene via CRISPR/Cas9 technology resulted in a significant decrease in the chlorophyll content. Overexpression of the RsGLK2.1 gene could restore the phenotype of the glk1glk2 mutant Arabidopsis. RsGLK2.1 was participated in regulating the chlorophyll biosynthesis by directly binding to the promoter of RsHEMA2 and activating its transcription. The interaction of RsNF-YA9a with RsGLK2.1 increased the transcriptional activity of the downstream gene RsHEMA2 under the light condition rather than the dark condition, indicating that both of them regulate the chlorophyll biosynthesis in a light-dependent manner of radish. Overall, these results provided insights into the molecular framework of the RsGLK2.1-RsNF-YA9a module, and could facilitate dissecting the regulatory mechanism underlying chlorophyll biosynthesis in green taproot of radish, and genetic improvement of quality traits in fruit radish breeding programs.

Keywords: GOLDEN2-LIKE; Green taproot; Photo-induced chlorophyll biosynthesis; RsHEMA2; RsNF-YA9a; Transcriptional regulation.

MeSH terms

Gene Expression Regulation, Plant
Plant Proteins* / genetics
Raphanus* / physiology

Substances

Plant Proteins