Browse Articles

Article|08 Nov 2023|OPEN
Characterization of PetM cytochrome b6f subunit 7 domain-containing protein in tomato
Mustafa Bulut1 , Adriano Nunes-Nesi2 , Alisdair R. Fernie1,3 , , Saleh Alseekh,1,3 ,
1Root Biology and Symbiosis, Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany
2Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa 36570-900 MG, Brazil
3Plant Metabolomics, The Center for Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
*Corresponding author. E-mail:,

Horticulture Research 11,
Article number: uhad224 (2024)
Views: 48

Received: 24 Feb 2023
Accepted: 29 Oct 2023
Published online: 08 Nov 2023


In recent years, multiple advances have been made in understanding the photosynthetic machinery in model organisms. Knowledge transfer to horticultural important fruit crops is challenging and time-consuming due to restrictions in gene editing tools and prolonged life cycles. Here, we characterize a gene encoding a PetM domain-containing protein in tomato. The CRISPR/Cas9 knockout lines of the PetM showed impairment in the chloroplastic electron transport rate (ETR), reduced CO2 assimilation, and reduction of carotenoids and chlorophylls (Chl) under several light conditions. Further, growth-condition-dependent elevation or repression of Chl a/b ratios and de-epoxidation states were identified, underlining possible impairment compensation mechanisms. However, under low light and glasshouse conditions, there were basal levels in CO2 assimilation and ETR, indicating a potential role of the PetM domain in stabilizing the cytochrome b6f complex (Cb6f) under higher light irradiance and increasing its quantum efficiency. This suggests a potential evolutionary role in which this domain might stabilize the site of the Cb6f regulating ratios of cyclic and linear electron transport and its potential importance during the conquest of terrestrial ecosystems during which plants were exposed to higher irradiance. Finally, the results are discussed with regard to metabolism and their implication to photosynthesis from an agronomic perspective.