Student Scholar Symposium Abstracts and Posters

Document Type

Chapman access only poster or presentation

Publication Date

Spring 5-2020

Faculty Advisor(s)

Dr. Hagop Atamian, Dr. Kenjiro Quides


In nature, plants interact with diverse microorganisms present in the soil. Some of these interactions are mutualistic, where both the plant and the soil microorganism benefit from the interaction. Legumes have established a unique mutualistic relationship with soil bacteria known as rhizobia. As part of this interaction, rhizobia enter the plant root and get housed in special structures on the root called nodules. Once established inside the nodule, rhizobia fix atmospheric nitrogen for the plant host in return for photosynthetic carbon. The plant interaction with the rhizobia greatly enhances plant productivity as they get access to usable form of nitrogen which is the most limiting macronutrient in agricultural production. However, this relationship between the plant and bacteria is very intricate and is influenced by many factors such as the plant variety, rhizobia species, soil nutrient composition, and ambient temperature. The objective of this project is to investigate the effect of time of the day on this interaction. Both plants and animals have internal biological clock that keep track of the time in the outside environment and accordingly adjust various physiological processes. We investigated the success of legume-rhizobia association by introducing the rhizobia to the plant every four-hour interval during a single day in a pouch system. Seeds of Lotus japonicus were germinated in growth pouches in sterile condition and grown for two weeks in 16 hr light/ 8 hr dark photoperiod under controlled environment. Mesorhizobium loti was cultured on a plate and a suspension of 10 billion cells/ml was prepared. The roots of two-week-old L. japonicus were inoculated with the bacterial suspension starting at dawn (ZT0) and every 4 hours until ZT20 (20 hours after dawn). Our results showed time of day effect in this interaction, where the interaction happened most efficiently at ZT12. The results from this project will help us better understand the complexity of this relationship and enable us to device new approaches to increase crop productivity.


Presented at the Spring 2020 Student Scholar Symposium at Chapman University.

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