VIRESCENT-ALBINO LEAF 1 regulates leaf colour development and cell division in rice.

Ting Zhang,Nan Wang,Ping Feng,Guoling Yu,Yunfeng Li,Tianquan Zhang,Junyang Huang,Yidan Li,Guanghua He,Xianchun Sang,Renhong Wu,Peng Yu,Fangming Zhao,Yinghua Ling,Changwei Zhang,Xiaoqin Zeng,Zhenglin Yang

doi:10.1093/jxb/ery250

Abstract

The de novo synthesis of purine nucleotides is crucial to all living organisms, but limited information is available for plants. In this study, we isolated a virescent-albino leaf 1 (val1) mutant of rice (Oryza sativa) that produces dynamic green-revertible albino and narrow-leaf phenotypes. In albino leaves, chloroplast development was defective, pigment contents were reduced, and cell division was impaired compared with the wild-type. Map-based cloning revealed that VAL1 encodes a phosphoribosylamine-glycine ligase (PurD), the second enzyme in the de novo purine biosynthesis pathway. Subcellular localization analysis demonstrated that VAL1 was localized in the chloroplast. Our results demonstrate that VAL1 is a crucial enzyme in the de novo purine biosynthesis pathway and is involved in regulating chloroplast development, chlorophyll metabolism, and cell division during leaf development in rice.

Highlights

Chloroplasts are semi-autonomous organelles responsible for the conversion of energy from sunlight, and for the synthesis of organic molecules by means of photosynthesis in higher plants
These results indicated that the albino-leaf phenotype of val1 in the early seedling stage was not affected by temperature, and we determined that val1 was a temperature-insensitive, green-revertible albino mutant
Metabolic pathways associated with chlorophyll synthesis and degradation, and chloroplast development have been elucidated, and mutation of genes involved in these metabolic pathways leads to changes in leaf colour

Summary

Introduction

Chloroplasts are semi-autonomous organelles responsible for the conversion of energy from sunlight, and for the synthesis of organic molecules by means of photosynthesis in higher plants. Chlorophyll is the primary photosynthetic pigment, and functions in the absorption and transformation of light energy into energy-storage molecules, carbohydrates, and oxygen; it is fundamental to the survival and reproduction of all living organisms (Fromme et al, 2003). Defective chloroplast development and chlorophyll metabolism lead to changes in chlorophyll content and leaf colour. Leaf-colour mutants are useful as markers in hybrid breeding, but can be used to study development-related processes such as photosynthesis, chlorophyll metabolism, and chloroplast development, and have considerable potential for research and practical application (Du et al, 2009). A substantial number of leaf-colour genes have been mapped, but only a few have been cloned.The two CAO

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