A temporal assessment of nematode community structure and diversity in the rhizosphere of cisgenic Phytophthora infestans-resistant potatoes

Abstract

BackgroundNematodes play a key role in soil processes with alterations in the nematode community structure having the potential to considerably influence ecosystem functioning. As a result fluctuations in nematode diversity and/or community structure can be gauged as a ‘barometer’ of a soil’s functional biodiversity. However, a deficit exists in regards to baseline knowledge and on the impact of specific GM crops on soil nematode populations and in particular in regard to the impact of GM potatoes on the diversity of nematode populations in the rhizosphere. The goal of this project was to begin to address this knowledge gap in regards to a GM potato line, cisgenically engineered for resistance to Phytophthora infestans (responsible organism of the Irish potato famine causing late blight disease). For this, a 3 year (2013, 2014, 2015) field experimental study was completed, containing two conventional genotypes (cvs. Desiree and Sarpo Mira) and a cisgenic genotype (cv. Desiree + Rpi-vnt1). Each potato genotype was treated with different disease management strategies (weekly chemical applications and corresponding no spray control). Hence affording the opportunity to investigate the temporal impact of potato genotype, disease management strategy (and their interaction) on the potato rhizosphere nematode community.ResultsNematode structure and diversity were measured through established indices, accounts and taxonomy with factors recording a significant effect limited to the climatic conditions across the three seasons of the study and chemical applications associated with the selected disease management strategy. Based on the metrics studied, the cultivation of the cisgenic potato genotype exerted no significant effect (P > 0.05) on nematode community diversity or structure. The disease management treatments led to a reduction of specific trophic groups (e.g. Predacious c–p = 4), which of interest appeared to be counteracted by a potato genotype with vigorous growth phenotype e.g. cv. Sarpo Mira. The fluctuating climates led to disparate conditions, with enrichment conditions (bacterial feeding c–p = 1) dominating during the wet seasons of 2014 and 2015 versus the dry season of 2013 which induced an environmental stress (functional guild c–p = 2) on nematode communities.ConclusionsOverall the functional guild indices in comparison to other indices or absolutes values, delivered the most accurate quantitative measurement with which to determine the occurrence of a specific disturbance relative to the cultivation of the studied cisgenic P. infestans-resistant potatoes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12898-016-0109-5) contains supplementary material, which is available to authorized users.

No Tangible Effects of Field-Grown Cisgenic Potatoes on Soil Microbial Communities

“…This study demonstrates with a highly sensitive molecular detection technique that soil bacterial and fungal communities, both likely to be influenced by plant-released products in the rhizosphere, respond to field site conditions, to annual variation, and, sporadically, to fungicides and potato varieties, but not to a cisgenic modification of a widely cultivated potato variety. Parallel studies at the same field sites using the same experimental design failed to detect tangible effects of this cisgenic potato on the soil nematode community structure (Ortiz et al, 2016) and on arthropod diversity (Lazebnik et al, 2017). Together, these studies demonstrate a lack of effects on non-target organisms and indicate no environmental risks associated with cultivating this cisgenic potato.…”

Using Nematode Community to Evaluate Banana Soil Food Web in Mekargalih, Cianjur, West Java

“…This study showed the highest abundance of c-p2 Cephalobidae (Agr1 34.9%) followed by the lowest EI coming from soil treated with fungicides (Agr1). Fungicide treatment was also associated with a decrease in predatory (omnivores and carnivores) and the low abundance of the bacterivore group (Ortiz et al, 2016;Yardim & Edwards, 1998). Predators on Agr1 (16.78%) were lower than Agr3 (17.65%) but higher than Agr2 (9.19%).…”

Communicating the risks of genetically modified organisms: lessons learnt from an Irish field of cisgenic potatoes

“…Included in AMIGA was a cisgenically modified potato line, previously developed through the Dutch DuRPh programme, which displayed a strong late blight resistant phenotype due to the presence of Rpi-vnt1.1 from Solanum venturii (Haverkort et al , 2016). As partners in AMIGA, we assessed the impact of this cisgenic GM potato line on specific parameters of soil biodiversity (versus its non-cisgenic comparator) across three years of field experimentation (Ortiz et al , 2016) in Ireland. Meanwhile, a spatio-temporal analysis completed on both the Irish and duplicated Dutch field sites validated integrated management strategies to support the durability of Rpi-vnt1.1 -mediated resistance (Kessel et al , 2018).…”