Spatial and Temporal Assessment of Pollen- and Seed-Mediated Gene Flow from Genetically Engineered Plum Prunus domestica

Abstract

Pollen flow from a 0.46 ha plot of genetically engineered (GE) Prunus domestica located in West Virginia, USA was evaluated from 2000–2010. Sentinel plum trees were planted at distances ranging from 132 to 854 m from the center of the GE orchard. Plots of mixed plum varieties and seedlings were located at 384, 484 and 998 m from the GE plot. Bee hives (Apis mellifera) were dispersed between the GE plum plot and the pollen flow monitoring sites. Pollen-mediated gene flow from out of the GE plum plot to non-GE plums under the study conditions was low, only occurring at all in 4 of 11 years and then in only 0.31% of the 12,116 seeds analyzed. When it occurred, gene flow, calculated as the number of GUS positive embryos/total embryos sampled, ranged from 0.215% at 132 m from the center of the GE plum plot (28 m from the nearest GE plum tree) to 0.033–0.017% at longer distances (384–998 m). Based on the percentage of GUS positive seeds per individual sampled tree the range was 0.4% to 12%. Within the GE field plot, gene flow ranged from 4.9 to 39%. Gene flow was related to distance and environmental conditions. A single year sample from a sentinel plot 132 m from the center of the GE plot accounted for 65% of the total 11-year gene flow. Spatial modeling indicated that gene flow dramatically decreased at distances over 400 m from the GE plot. Air temperature and rainfall were, respectively, positively and negatively correlated with gene flow, reflecting the effects of weather conditions on insect pollinator activity. Seed-mediated gene flow was not detected. These results support the feasibility of coexistence of GE and non-GE plum orchards.

Isolation Distances for Transgenic Alfalfa Seed Production in the Pacific Northwest

“…Similar to other studies (Fitzpatrick et al, 2003; Teuber et al, 2004; Fitzpatrick et al, 2007a; Hagler et al, 2011; Rieben et al, 2011; Scorza et al, 2013; Dong et al, 2016), results from our quadratic regression indicated that AP significantly decreased as the distance from GE fields increased. Results from our spatial prediction map showed similar results.…”

“…Whereas exponential decay models have been used to study the movement of transgenes into non‐GE crops (Fitzpatrick et al, 2003; Teuber et al, 2004; Hagler et al, 2011; Scorza et al, 2013; Dong et al, 2016), we elected to use a quadratic regression approach, which has fewer assumptions and can assume a wider variety of decay shapes than an exponential model. We used a logit transformation on proportion of AP, log[ p /(1 − p )], where a small amount of positive noise was added to zero counts to avoid taking the log of zero.…”

Pollinizer Efficacy of Several ‘Ingeborg’ Pear Pollinizers in Hardanger, Norway, Examined Using Microsatellite Markers

“…Pollinator activity may be adversely affected by low temperatures and excessive rainfall during bloom (Scorza et al, 2013). Excessive rainfall may also hinder the diffusion of floral nectar scent (Yan et al, 2016).…”

Crop biotechnology: a pivotal moment for global acceptance

“…Gene flow was detected in only four of the 11 years and then in only 0.31% of over 12,000 seeds tested. The results of the study suggested that a 400-m distance from non-GE plums would allow for coexistence (Scorza et al 2013b). Bees were considered the most likely vector for pollen movement.…”

“…The results of the study suggested that a 400‐m distance from non‐GE plums would allow for coexistence (Scorza et al. ). Bees were considered the most likely vector for pollen movement.…”