Development of transgenic tomato (Solanum lycoperscicum L.) by heterologous expression of osmotin-like protein (OLP) and chitinase (Chi11) genes for salt and drought stress tolerance

Tomato (Solanum lycopersicum L.) is the second most produced and consumed vegetable, next to potato. Pusa early dwarf (PED) variety of tomato is sensitive to salinity and drought which reduces the yield and fruit quality in tomato. In the present study, tomato transgenics were developed with osmotin-like protein (OLP) and chitinase (Chi11) genes via in vitro and in planta transformation methods. Transgene integration and transcript levels were confirmed by multiplex PCR, DNA blot, and multiplex reverse transcriptase PCR. Homozygous T2 transgenics, when evaluated for salt and drought stress, showed enhanced tolerance compared to wild-type plants. Transgenics showed enhanced root biomass under normal conditions. Transformants also displayed higher proline content, K+, relative water content, chlorophyll fluorescence, total biomass, vascular conductivity, and fruit yield compared to the wild-type plants under stress conditions. Co-immunoprecipitation revealed that Chi11 co-expresses with phosphofructokinase2 (PFK2), which may play a role in enhanced root biomass. qPCR analysis resulted in higher transcript levels of OLP, Chi11, and PFK2 in transgenics as compared to the wild-type plants