Evaluation of cytokinin producing Methylobacterium as an inoculant for seedling performance, yield improvement, and drought and salt stress tolerance in pea
Dr. Neil Emery
Lead Investigator(s) Institution
To investigate a collection of plant endophytes of Methylobacterium for their capability to enhance seedling performance, improve yield parametres, and increase plant tolerance to mild-drought and saline-soil stresses during germination, vegetative and generative growth stages
Beneficial bacteria that live in symbiosis with crop plants are gaining a lot of attention as a new, environmentally friendly alternative to traditional, chemical fertilizers and pesticides. In nature, bacteria inhabit surfaces and live inside plant tissues. However, not all of these microbes possess growth promoting characters, such as: production of plant hormones, increasing nutrient supply to plants, or enhancing host resistance to pathogens. Successful application of bioinoculants in agricultural production is highly dependent on the selection of the right type of microbes. Bacteria used as components of natural biofertilizers have to improve plant growth and development, but they also need to be well adapted to environmental conditions of field sites. This project investigated beneficial effect of plant inoculation with symbiotic Methylobacterium on four legume species: chickpea, pea, lentil and faba bean, exposed to limited water supply during early growth stages and at flowering. All control and inoculated plants were cultivated in specially designed growth rooms with a fully controlled light, temperature and irrigation regime. The Methylobacterium strain was selected based on its ability to produce high levels of active plant growth hormones called cytokinin, and simultaneous high tolerance to drought, that we tested in a series of in vitro laboratory screenings prior to plant treatments. The experiments conducted in this project revealed a positive effect of bacteria on plant performance, both in control and drought stress conditions. Plant inoculation stimulated germination, early growth and general plant vigour, with no particular differences observed between the four legume species. Inoculated plants were characterized by more efficient water management during drought period, increased levels of cytokinins and higher rates of photosynthesis. By increasing the overall plant performance, the presence of Methylobacterium ultimately offset the negative effect of limited water availability. Therefore, the applied biofertilizer helped to improve yield parametres, especially the harvest index. In an era of climate change where reduced rainfall and expansion of arid areas significantly limits farmland productivity, our results suggest that introduction of Methylobacterium inoculants to farming practices may help in plant adaptation to adverse growth conditions and allow for successful production even in regions not very suitable for crop cultivation.
Duration/Timeline of Project (Year to Year)
2015 - 2017