ИСТИНА

MADS-domain transcription factors are involved in specifying meristem and organ identity. Tomato LeMADS5 is the Arabidopsis SEP3 homologue with a putative significant role in fruit development and ripening. The present work is focused on the natural LeMADS5 diversity in wild and cultivated tomato species. Using designed LeMADS5-specific primers, complete LeMADS5 genes of S. pimpinellifolium and S. peruvianum were identified. As compared to S. lycopersicum cv. Heinz LeMADS5, genes contain indels and synonymous and non-synonymous SNPs. Based on obtained LeMADS5 sequences, RT-PCR primers were designed, and LeMADS5 expression was examined in flowers, mature green (MG) and ripe (RF) fruits of cultivated and wild tomato species differing in fruit morphophysiology. S. lycopersicum var. humboldtii and S. lycopersicum cv. Silvestre recordo LeMADS5 transcription levels were relatively uniform with the peak in flowers and minimum in RF fruits that was similar to the only described cv. Micro-Tom. In heirloom species S. pimpinellifolium, LeMADS5 was equally expressed in flowers and RF fruits, with maximum in MG fruits. In other wild species S. cheesmaniae, S. neorickii, S. peruvianum, S. peruvianum var. dentatum, S. arcanum, and S. habrochaites, LeMADS5 transcription was 6–20-times higher in fruits compared to flower-specific expression, which was 5-times lower than in S. lycopersicum. Furthermore, S. neorickii and S. habrochaites LeMADS5 expression was highest in RF fruits, while in other species the peak of LeMADS5 expression was in MG fruits. Polymorphism of LeMADS5 genomic and derived protein sequences, as well as different LeMADS5 expression mode in wild and cultivated tomatoes besides conserved role for LeMADS5 in fruit development and ripening may suggest but with some distinctive properties linked to the diverse flower and fruit characteristics. The study was supported by the Russian Science Foundation grant 16-16-10022.