Vertically transmitted endophyte improved plant-rhizobacteria interaction
Posted 14th January 2020 by Joshua Sewell
Plant growth-promoting bacteria (PGPB) have been identified as potential biofertilizers, eco-friendly, renewable and have been demonstrated to actively restore soil fertility. Beyond this, they have been shown to be a promising biological resource to augment chemical fertilizer, and drastically reduce its application and subsequent negative effects.
The use of the PGPB mechanism in modulating plant root and improving nutrient uptake such as phosphorus, iron, nitrogen-fixation and stimulation of phytohormone has recently inspired a wide range of commercials production and application in the agricultural sector.
Intensive studies are still going on the dynamic of plant-microbial interaction for improving plant health, growth and defence using different model, one good example of this is the Zigzag model that has been used to elucidate the steps involved in microbial trigger plant defence, known as pattern triggered immunity (PTI). Consider being the first line of defence by the plant using protein recognition receptor (PRRs) that bind conserved compound known as the pathogen-associated molecular pattern (PAMPs), while the second line of defence according to this model is the effector trigger immunity (ETI).
A kind of defence that involved a gene with leucine-rich repeat biding site; resistance gene that code for microbial virulence effector protein. To identified and maximized the effective result of biofertilizer, various delivery method has been exploited such as the seeds inoculation, foliar spray inoculation and the rhizosphere microbial community restructuring through direct soil inoculation.
Even though extensive data have been documented on microbial aided plant improved growth, yield and resistance to pathogens, however, the recent concern of inconsistency in achieving the desired result in some field application needs to be addressed. To harness this potential eco-friendly biofertilizer there is a need for an innovative solution, by re-investigate how endophyte-rhizobacteria communicate and how this influence plant-microbial interaction in promoting plant health growth and yield.
To identify a novel approach to this challenge, we used cultivars with naturally selected vertically transmitted endophyte and those void of any vertically transmitted endophyte i.e. identify each cultivar’s existing vertical transmitted endophyte and observed the cultivar’s corresponding responds to different rhizosphere microbial community in regarding their growth, chlorophyll content, and weight. Solanum Lycopersicum being one of the most preferred vegetables globally is an excellent model plant, a vegetable plant with recorded major diseases caused by 41 different fungi, 10 different bacteria, 15 different viruses, 1 phytoplasma and 14 different nematodes according to (Phytopathological society of japan as in 2000).
These are the characteristics that motivate our choice of Solanum Lycopersicum as the model plant. While the microbial communities are isolated from manure treated plot, fertilizer treated plot and an untreated plot collected from an experimental farm, Lea palace Newcastle University. The study demonstrates that two bacterial genera and fungi co-exist as the inhabitant of Solanum Lycopersicum seeds.
Phylogenetic analysis demonstrates that these two bacterial genera recover from Solanum Lycopersicum seeds share ancestral linkage and both can form endospore during osmotic pressure and starch accumulation, the study further demonstrates that these endophytes had significantly different phenotypes in terms of their plant growth-promoting potential. Evident of vertically transmitted endophyte priming the plant-rhizobacterial interaction has also been demonstrated.
Finally, the study demonstrates that the presence of fertilized soil rhizobacterial communities in hydroponically grown tomato cultivars positively influences the chlorophyll content, salicylic acid and weight of the plant. The finding demonstrates that whilst plant-microbial interaction can improve plant growth and development, there is a need for cultivar’s vertical transmitted endophyte to be identified for tailor microbial communities planting.
Victor Irimiya Danladi is a PhD candidate at Newcastle University. He presented this poster at the 4th Partnerships in Biocontrol, Biostimulants and Microbiome Congress: USA.