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Article|01 Jun 2021|OPEN
Mutation of SlARC6 leads to tissue-specific defects in chloroplast development in tomato
Jiang Chang1, Haiyang Qin1, Peng Liu1, Fanyu Zhang1, Jianfeng Wang1 & Shuang Wu1,
1College of Horticulture, FAFU-UCR Joint Center and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China

Horticulture Research 8,
Article number: 127 (2021)
doi: 10.1038/hortres.2021.127
Views: 209

Received: 16 Jun 2020
Revised: 21 Mar 2021
Accepted: 26 Mar 2021
Published online: 01 Jun 2021

Abstract

The proliferation and development of chloroplasts are important for maintaining the normal chloroplast population in plant tissues. Most studies have focused on chloroplast maintenance in leaves. In this study, we identified a spontaneous mutation in a tomato mutant named suffulta (su), in which the stems appeared albinic while the leaves remained normal. Map-based cloning showed that Su encodes a DnaJ heat shock protein that is a homolog of the Arabidopsis gene AtARC6, which is involved in chloroplast division. Knockdown and knockout of SlARC6 in wild-type tomato inhibit chloroplast division, indicating the conserved function of SlARC6. In su mutants, most mesophyll cells contain only one or two giant chloroplasts, while no chloroplasts are visible in 60% of stem cells, resulting in the albinic phenotype. Compared with mature tissues, the meristem of su mutants suggested that chloroplasts could partially divide in meristematic cells, suggesting the existence of an alternative mechanism in those dividing cells. Interestingly, the adaxial petiole cells of su mutants contain more chloroplasts than the abaxial cells. In addition, prolonged lighting can partially rescue the albinic phenotypes in su mutants, implying that light may promote SlACR6-independent chloroplast development. Our results verify the role of SlACR6 in chloroplast division in tomato and uncover the tissue-specific regulation of chloroplast development.