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Article|01 Nov 2021|OPEN
OBV (obscure vein), a C2H2 zinc finger transcription factor, positively regulates chloroplast development and bundle sheath extension formation in tomato (Solanum lycopersicum) leaf veins
Jinghua Lu1, Chunyang Pan1, Xin Li1, Zejun Huang1, Jinshuai Shu1, Xiaoxuan Wang1, Xiaoxiao Lu1, Feng Pan1, Junling Hu1, Hui Zhang1, Wenyue Su1, Min Zhang1, Yongchen Du1, Lei Liu1, Yanmei Guo1, & Junming Li1,
1Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of Ministry of Agriculture, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China

Horticulture Research 8,
Article number: 230 (2021)
doi: 10.1038/hortres.2021.230
Views: 52

Received: 26 Mar 2021
Revised: 07 Jul 2021
Accepted: 14 Jul 2021
Published online: 01 Nov 2021

Abstract

Leaf veins play an important role in plant growth and development, and the bundle sheath (BS) is believed to greatly improve the photosynthetic efficiency of C4 plants. The OBV mutation in tomato (Solanum lycopersicum) results in dark veins and has been used widely in processing tomato varieties. However, physiological performance has difficulty explaining fitness in production. In this study, we confirmed that this mutation was caused by both the increased chlorophyll content and the absence of bundle sheath extension (BSE) in the veins. Using genome-wide association analysis and map-based cloning, we revealed that OBV encoded a C2H2L domain class transcription factor. It was localized in the nucleus and presented cell type-specific gene expression in the leaf veins. Furthermore, we verified the gene function by generating CRISPR/Cas9 knockout and overexpression mutants of the tomato gene. RNA sequencing analysis revealed that OBV was involved in regulating chloroplast development and photosynthesis, which greatly supported the change in chlorophyll content by mutation. Taken together, these findings demonstrated that OBV affected the growth and development of tomato by regulating chloroplast development in leaf veins. This study also provides a solid foundation to further decipher the mechanism of BSEs and to understand the evolution of photosynthesis in land plants.