Investigation of the effect of entomopathogenic Serratia marcescens isolates on the development of tomato (Solanum lycopersicum L.) plant

Although chemical herbicides, pesticides and fertilizers used in crop production have positive effects in the short term, they cause both soil pollution and negative effects on human health due to residue problems in the products. The use of microorganisms as biofertilizers to reduce or even eliminate the use of such chemicals is a broad field of research. In addition, the use of insect pathogenic bacteria as biofertilizers, as well as plant growth promoting bacteria has recently become an important field of research. In this study, the effects of two different local isolates of the entomopathogenic Serratia marcescens bacteria (Sm-Se9 and Sm-MK11) on the growth and development of tomato plants were investigated. To determine the usability in the field, soils from greenhouses where tomatoes are grown in Bilecik were used both sterile and steril olmayane and grown in the presence of microorganisms. The morphological data obtained from the study (percentage of germination, root-stem length, stem diameter and biomass) showed that the S. marcescens isolates did not contribute positively to the growth and development of the tomato plants, but even had a negative effect. However, it was shown that plants grown in sterile soil grew better than those grown in steril olmayane soil. It was also found that the photosynthetic efficiency of plants grown in the presence of microorganisms was twice as high as that of the control. When lipid peroxidation was assessed, it was found that the plants grown in sterile soil grew healthier and the plants grown in the presence of microorganisms had a lower MDA content than the control group. When the enzyme levels in the antioxidant system were analysed, it was found that the antioxidant capacity of the plants in which the isolates were used was higher than that of the control. In the results of bacterial re- isolation, it was found that the isolates used colonized the roots of the plant and reached the stem and even the leaves via the vascular system. This showed that the Serratia marcescens isolates used did not contribute positively to the growth and development of the plant, but had endophytic properties.