College of Forest Resources and Environment, Nanjing Forestry University, Nanjing, Jiangsu, China ; Key Biosafety Laboratory in Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection of China, Nanjing, Jiangsu, China ; Liaoning Agricultural College, Yingkou, Liaoning, China.
PLoS One. 2013 Dec 6;8(12):e82199. doi: 10.1371/journal.pone.0082199. eCollection 2013.
Elevated tropospheric ozone severely affects not only yield but also the morphology, structure and physiological functions of plants. Because of concerns regarding the potential environmental risk of transgenic crops, it is important to monitor changes in transgenic insect-resistant rice under the projected high tropospheric ozone before its commercial release.
METHODOLOGY/PRINCIPAL FINDINGS: Using a free-air concentration enrichment (FACE) system, we investigated the changes in leaf morphology and leaf ultrastructure of two rice varieties grown in plastic pots, transgenic Bt Shanyou 63 (Bt-SY63, carrying a fusion gene of cry1Ab and cry1Ac) and its non-transgenic counterpart (SY63), in elevated O3 (E-O3) versus ambient O3 (A-O3) after 64-DAS (Days after seeding), 85-DAS and 102-DAS. Our results indicated that E-O3 had no significant effects on leaf length, leaf width, leaf area, stomatal length and stomatal density for both Bt-SY63 and SY63. E-O3 increased the leaf thickness of Bt-SY63, but decreased that of SY63. O3 stress caused early swelling of the thylakoids of chloroplasts, a significant increase in the proportion of total plastoglobule area in the entire cell area (PCAP) and a significant decrease in the proportion of total starch grain area in the entire cell area (SCAP), suggesting that E-O3 accelerated the leaf senescence of the two rice genotypes. Compared with SY63, E-O3 caused early swelling of the thylakoids of chloroplasts and more substantial breakdown of chloroplasts in Bt-SY63.
CONCLUSIONS/SIGNIFICANCE: Our results suggest that the incorporation of cry1Ab/Ac into SY63 could induce unintentional changes in some parts of plant morphology and that O3 stress results in greater leaf damage to Bt-SY63 than to SY63, with the former coupled with higher O3 sensitivity in CCAP (the proportions of total chloroplast area in the entire cell area), PCAP and SCAP. This study provides valuable baseline information for the prospective commercial release of transgenic crops under the projected future climate.
对流层臭氧浓度升高不仅严重影响作物的产量，还会影响植物的形态、结构和生理功能。由于对转基因作物潜在环境风险的担忧，在其商业释放之前，监测预计高浓度对流层臭氧下转基因抗虫水稻的变化非常重要。
方法/主要发现：使用自由空气浓度富集（FACE）系统，我们研究了在升高的臭氧（E-O3）与环境臭氧（A-O3）下，转 Bt 汕优 63（Bt-SY63，携带 cry1Ab 和 cry1Ac 融合基因）和其非转基因对照品（SY63）的两种水稻品种的叶片形态和叶片超微结构的变化，在播种后 64 天（DAS）、85 DAS 和 102 DAS 时。我们的结果表明，E-O3 对 Bt-SY63 和 SY63 的叶长、叶宽、叶面积、气孔长度和气孔密度均没有显著影响。E-O3 增加了 Bt-SY63 的叶片厚度，但降低了 SY63 的叶片厚度。O3 胁迫导致叶绿体类囊体早期肿胀，整个细胞面积中总质体小球面积的比例（PCAP）显著增加，整个细胞面积中总淀粉粒面积的比例（SCAP）显著降低，表明 E-O3 加速了两种水稻基因型的叶片衰老。与 SY63 相比，E-O3 导致 Bt-SY63 叶绿体类囊体早期肿胀，叶绿体破坏更为严重。
结论/意义：我们的结果表明，将 cry1Ab/Ac 导入 SY63 可能会导致植物形态的某些部分发生无意识的变化，并且 O3 胁迫会导致 Bt-SY63 的叶片损伤大于 SY63，前者与 CCAP（整个细胞面积中的总叶绿体面积的比例）、PCAP 和 SCAP 中的 O3 敏感性更高有关。本研究为未来气候下转基因作物的预期商业释放提供了有价值的基线信息。
