A GATA Transcription Factor from Soybean (Glycine max) Regulates Chlorophyll Biosynthesis and Suppresses Growth in the Transgenic Arabidopsis thaliana.

Chanjuan Zhang,Limiao Chen,Zhiyuan Xiao,Wenjun Huang,Haifeng Chen,Yi Huang,Qingnan Hao,Xinan Zhou,Shuilian Chen,Hongli Yang,Songli Yuan

doi:10.3390/plants9081036

Abstract

Chlorophyll plays an essential role in photosynthetic light harvesting and energy transduction in green tissues of higher plants and is closely related to photosynthesis and crop yield. Identification of transcription factors (TFs) involved in regulating chlorophyll biosynthesis is still limited in soybean (Glycine max), and the previously identified GmGATA58 is suggested to potentially modulate chlorophyll and nitrogen metabolisms, but its complete function is still unknown. In this study, subcellular localization assay showed that GmGATA58 was localized in the nucleus. Histochemical GUS assay and qPCR assay indicated that GmGATA58 was mainly expressed in leaves and responded to nitrogen, light and phytohormone treatments. Overexpression of GmGATA58 in the Arabidopsis thaliana ortholog AtGATA21 (gnc) mutant complemented the greening defect, while overexpression in Arabidopsis wild-type led to increasing chlorophyll content in leaves through up-regulating the expression levels of the large of chlorophyll biosynthetic pathway genes, but suppressing plant growth and yield, although the net photosynthetic rate was slightly improved. Dual-luciferase reporter assay also supported that GmGATA58 activated the transcription activities of three promoters of key chlorophyll biosynthetic genes of soybean in transformed protoplast of Arabidopsis. It is concluded that GmGATA58 played an important role in regulating chlorophyll biosynthesis, but suppressed plant growth and yield in transgenic Arabidopsis.

Highlights

Photosynthesis, a major contributor to crop yield, predominantly takes place in leaves where chlorophyll, one of the most abundant biological molecules in higher plants, plays unique and essential roles in photosynthetic light harvesting and energy transduction [1]
The full-length cDNA of GmGATA58 gene was amplified from soybean variety ‘TianLong No.10 and it contained an entire ORF of 969 bp, encoding a protein of 322 amino acid
The results showed the GFP::GmGATA58 fusion protein fluorescent signal only transient in the nucleus, which completely overlaid the red fluorescence produced driven by the CaMV 35Sapromoter produced a strong green fluorescent signal only in the from AtFib2-mCherry, well-known nucleolar marker

Summary

Introduction

Photosynthesis, a major contributor to crop yield, predominantly takes place in leaves where chlorophyll, one of the most abundant biological molecules in higher plants, plays unique and essential roles in photosynthetic light harvesting and energy transduction [1]. It has been reported that chlorophyll concentration, specific leaf weight or area and photosynthetic rate have impacts on crop yield, including soybean [2,3,4]. It is suggested that improving photosynthetic efficiency in soybean through biotechnology is a promising alternative way to increase crop yield [6]. It was previously documented that the photosynthetic rate of soybean was highly correlated with chlorophyll content in leaves [7]. It is possible to improve photosynthesis rate and crop yield through increasing chlorophyll content in leaves

Methods

Results

Discussion

Conclusion