Photosynthetic apparatus in a cytoplasmic hybrid of cultured tomato carrying the nucleocytoplasmic incompatibility trait

Photosynthetic characteristics of cytoplasmic hybrid Lycopersicon esculentu m + L, peruvianum var. dentatum, which had been constructed by means of som atic hybridization, were investigated. This hybrid contained L. peruvianum var. dentatum Dun. plastome, reconstructed chondriome, and possessed phenot ypic traits of nucleocytoplasmic incompatibility. Investigation of the cont ent of photosynthetic pigments in the cytoplasmic hybrid L. esculentum + L. peruvianum var, dentatum, tomato plant L, esculentum Mill. (cultivars Qued linburger Fruhe Liebe,), and a wild species L, peruvianum var. dentatum Dun . (line 3767) showed that the total chlorophyll a and b content was 1.2-1.6 lower in the hybrid than in parental species. Analysis of chlorophyll-prot ein complexes by SDS-PAGE showed that the content of PS I reaction center c omplexes (CP1a and CP1) was reduced in the cytoplasmic hybrid. Analysis of fluorescence induction curves of leaves and low-temperature fluorescence sp ectra of chloroplasts revealed significant changes in the structural organi zation and functional activity of the photosynthetic apparatus in the cytop lasmic hybrid L. esculentum + L. peruvianum var. dentatum. The hybrid exhib ited changes in chlorophyll forms of the PS I antenna, a decrease in photoc hemical activity and the efficiency of dark metabolism, as well as the impa irment of electron transfer between PS I and PS II. The genotypes examined markedly differed in CO2 exchange rate. Photosynthetic rate was 1.3 and 1.9 lower in the cytoplasmic hybrid than in tomato plant and wild type, respec tively. These alterations in the photosynthetic apparatus of the cytoplasmi c hybrid of cultured tomato confirm the incompatibility of the nuclear geno me of L. esculentum with plasmagenes of L. peruvianum var. dentatum, which was revealed previously at the phenotypic level.