Abstract Detail

Symbioses: Plant, Animal, and Microbe Interactions

Pec, Gregory [1], Breight, Michael [1], Twigg, Paul [1], Shaffer, Julie [1].

Rhizosphere bacterial diversity and composition varies across Zea mays growth stages.

The rhizosphere, a region of soil in the vicinity of plant roots, is strongly influenced by a plant’s growth, respiration, nutrient exchange and root secretions. Within this soil zone, bacterial communities, known to be highly diverse and vital to plant growth and productivity, are suggested to be strongly dependent on various attributes of the host-plant including growth stage (i.e., vegetative (VE-VT) versus reproductive (R1-R6)). Here, we used a globally important crop, Zea mays, to investigate the effects of plant developmental stage on rhizosphere bacterial diversity and composition. We hypothesized that plant growth stage would influence root physiology, and thus changes to the quality and quantity of root exudates would consequently exert a selection on rhizosphere associated bacteria. We chose a continuously cropped agricultural field based on historical yield data to minimize the effects of crop management and soil properties on the response of bacterial communities to Z. mays. Overall, there was a one-fold decline in bacterial diversity during the V12 and R5 stages of Z. mays plant growth. The composition of rhizosphere bacterial communities differed from early to late stage Z. mays development. When looking more specifically at the response of certain bacterial groups, the relative sequence abundance of Acidobacteria declined by half from the VE to the R5 growth stage. In contrast, there was a one-fold increase in the relative sequence abundance of unknown bacteria from VE/V4 to the R1/R5 growth stages. Within Proteobacteria, the relative sequence abundance of both alpha- and gamma-Proteobacteria declined by one-fold during the V12 Z. mays growth stage; whereas, unclassified Proteobacteria increased across all Z. mays growth stages. Taken together, our findings suggest that rhizosphere bacterial diversity and composition is strongly linked to the growth stage of the host-plant.

1 - University of Nebraska at Kearney , Department of Biology, 2401 11th Avenue , Kearney , NE , 68849 , USA

Keywords:
Rhizosphere
bacteria
Zea mays
plant development.

Presentation Type: Oral Paper
Session: SYMB2, Symbioses: Plant, Animal, and Microbe Interactions II
Location: Virtual/Virtual
Date: Wednesday, July 29th, 2020
Time: 10:00 AM
Number: SYMB2001
Abstract ID:135
Candidate for Awards:None