Transgenic tomato overexpressing ath-miR399d improves growth under abiotic stress conditions

Abstract

Phosphorus (P) is an essential element required for plant growth and development. Abiotic stresses, such as cold and P deficiency cause adverse effects on growth of plants, inhibit accumulation or translocation of mineral nutrients such as P, and often constrain the productivity and quality of crops. miR399 as a long-distance signal controls systemic phosphate homeostasis by modulating phosphate uptake and transport. However, overexpression of miR399 causes P toxicity and results in retarded growth. Thus, we constructed a transgenic tomato (Solanum lycopersicum L., C1), which contains foreign gene ath-miR399d under the control of rd29A promoter. In the transgenic C1 expression of the miR399d gene showed a stress-inducible pattern. Results showed that miR399d was moderately up-regulated in response to salinity and cold stresses. In soil, dry weight was enhanced in transgenic tomato under low temperature and P deficiency conditions. The transgenic tomato has potential to improve growth when it is exposed to other abiotic stresses such as salinity and drought.