Investigation of the effects of miR408 and PDH45/47 overexpression on plant drought resistance mechanisms

In this study, genetic transformation of the miR408 gene was carried out on tomato and canola plants by Agrobacterium tumefaciens. F1 tomato lines were obtained in tomato plants formed by overexpression of miR408 gene were investigated at biochemical and molecular levels. Control and transgenic plant tissue extraction were carried out; on days 3–6 of drought stress and on days 3–10 of salinity stress. The responses of plants were examined comparatively. Expression levels of stress-sensitive target genes were measured using qRT–PCR. Control and transgenic plants subjected to drought and salt treatments on both stress days, was determined that proline levels increased, RWC content decreased, MDA and ion leakage levels, changes independent of stress application and miR408 expression. On the 6th day of drought and 3–10 days of salinity, it was determined that transgenic plants total chlorophyll contents were at a better level compared to control plants with increasing stress their preserved. In transgenic tomato plants with overexpression of miR408; MAPK3, CPK2, GR1, APX1, and FeSOD target gene expression increased as the drought stress duration increased. However, in salinity stress, as duration of stress increases, a decrease in gene expression is observed. Additionally, gene expression was not detected in transgenic+control plants exposed to salinity for 10-day genes GR1, APX1, FeSOD, CAT2. Our results confirm drought stress tolerance of transgenic tomatoes because of overexpression of miR408. Under salinity stress, no effect of miR408 expression increase on plant stress tolerance was observed in applied stress severity and duration.