Movement and Motion of Soybean Cyst Nematode Heterodera glycines Populations and Individuals in Response to Abamectin

Abstract

Two new in vitro methods were developed to analyze plant-parasitic nematode behavior, at the population and the individual organism levels, through time-lapse image analysis. The first method employed a high-resolution flatbed scanner to monitor the movement of a population of nematodes over a 24-h period at 25°C. The second method tracked multiple motion parameters of individual nematodes on a microscopic scale, using a high-speed camera. Changes in movement and motion of second-stage juveniles (J2) of the soybean cyst nematode Heterodera glycines Ichinohe were measured after exposure to a serial dilution of abamectin (0.1 to 100 μg/ml). Movement and motion of H. glycines were significantly reduced as the concentration of abamectin increased. The effective range of abamectin to inhibit movement and motion of H. glycines J2 was between 1.0 and 10 μg/ml. Proof-of-concept experiments for both methods produced one of the first in vitro sensitivity studies of H. glycines to abamectin. The two methods developed allow for higher-throughput analysis of nematode movement and motion and provide objective and data-rich measurements that are difficult to achieve from conventional microscopic laboratory methods.

Avicta and Clariva Affect the Biology of the Soybean Cyst Nematode, Heterodera glycines

“…Significant effects were observed on J2 movement and penetration at several soil depths. In previous experiments, we found that H. glycines was sensitive to abamectin at concentrations of 1-10 mg/ml (Jensen et al 2018). A similar concentration of 1.56 mg/ml was reported to paralyze M. incognita (Faske and Starr 2006).…”

“…Nematodes incubated in leachates of soil planted with treated seeds and in control solutions were analyzed using motion analysis of individual nematodes described by Jensen et al (2018). J2s in 30 ml of suspension from the treatments described above were placed on a microscope slide with coverslip and observed with overhead light microscopy (Leica LED 5000 light attached to Leica M205 C stereoscope) at 63× magnification (6.3× magnification, 10× eyepiece, and 1× camera).…”

Scan4CFU: Low-cost, open-source bacterial colony tracking over large areas and extended incubation times

“…An example of open source hardware and software for the automated counting of bacterial colonies showed that high-resolution images from flatbed scanners (1200 dpi and higher) were superior than those from digital cameras for bacterial enumeration [16]. Besides applications in microbiology, our bacterial enumeration system can be diversified for imaging, counting, and tracking other microorganisms on agar plates, such as C. elegans and parasitic nematodes [17][18][19][20]. For this purpose, a number of open source image processing and analysis techniques are freely available through the ImageJ software and the scientific imaging community [14,21,22].…”

Effects of nematicidal seed treatments on the biology of the soybean cyst nematode, Heterodera glycines

“…Significant effects were observed on J2 movement and penetration at several soil depths. In previous experiments, we found that H. glycines was sensitive to abamectin at concentrations of 1 to 10 μg/ml (Jensen et al 2017). A similar concentration of 1.56 μg/ml was reported to paralyze M.…”

“…Nematodes incubated in leachates of soil planted with treated seeds and in control solutions were analyzed using motion analysis of individual nematodes described by Jensen et al 2017. J2s in 30 ml of suspension from the treatments described above were placed on a microscope slide with coverslip and observed with overhead light microscopy (Leica LED 5000 light attached to Leica M205 C stereoscope) at 63x magnification (6.3x magnification, 10x…”