| Over the past century, changes in farming practices have resulted in an enormous increase in agricultural productivity. Substantial gains in crop yields were due to several factors, including the use of nitrogen fertilizers and pesticides (Youngquist, 1999). These chemicals are primarily derived from fossil fuels, such as petroleum and natural gas. Considering these are both finite resources, there is a need to develop alternative technologies that boost crop productivity in a sustainable way. Recent studies have proposed the use of endophytes to promote plant growth and increase yields. One specific endophyte, Enterobacter sp. 638, has been shown to enhance plant growth in a variety of hosts. E. 638 produces plant hormones which result in increased biomass (Taghavi et al., 2011). This study measures the effects of inoculation with E. 638 on growth and gene expression in tomato (Solanum lycopersicum ). Two factors, inoculation and stress, were examined for their effects on time to flower, time to first produce fruit and first ripening event, as well as total mass of fruit and vegetative tissue. Stressed conditions were simulated by growing tomato plants in small (19 L) pots in a greenhouse, while unstressed plants were placed outside in larger (∼57 L) pots to minimize restriction of root growth and maintain a more natural environment.;Furthermore, this study used qPCR to measure the relative expression of genes involved in auxin transport, cytokinin signaling, ethylene signaling and cell wall expansion in tomato roots. The effects of inoculation on gene expression between control and exposed plants were compared. The results of this study may have major implications to agriculture by reducing cost and reliance on petroleum based chemicals, as well as to the field of plant physiology. Understanding how plants respond to inoculation with E. 638 may lead to a better understanding of plant responses to external stimuli. |
