The evolutionary significance of introgression has been discussed for decades. Questions about potential impacts of transgene flow into wild and weedy populations brought renewed attention to the introgression of crop alleles into those populations. In the past two decades, the field has advanced with considerable descriptive, experimental, and theoretical activity on the dynamics of crop gene introgression and its consequences. As illustrated by five case studies employing an array of different approaches, introgression of crop alleles has occurred for a wide array of species, sometimes without significant consequence, but on occasion leading to the evolution of increased weediness. A new theoretical context has emerged for analyzing empirical data, identifying factors that influence introgression, and predicting introgression's progress. With emerging molecular techniques and analyses, research on crop allele introgression into wild and weedy populations is positioned to make contributions to both transgene risk assessment and reticulate evolution.

Eosin Y, a well-known economical alternative to metal catalysts in visible-light-driven single-electron transfer-based organic transformations, can behave as an effective direct hydrogen-atom transfer catalyst for C-H activation. Using the alkylation of C-H bonds with electron-deficient alkenes as a model study revealed an extremely broad substrate scope, enabling easy access to a variety of important synthons. This eosin Y-based photocatalytic hydrogen-atom transfer strategy is promising for diverse functionalization of a wide range of native C-H bonds in a green and sustainable manner.

Weedy rice populations from Liaoning are considerably variable genetically and most probably originated from Liaoning rice varieties by mutation and intervarietal hybrids. Recent changes in farming practices and cultivation methods along with less weed management may have promoted the re-emergence and divergence of weedy rice in North-eastern China.

Research Summary• Genetically modified (GM) rice with enhanced agronomic traits and pharmaceutical uses are ready for widespread adoption. Little is known about isolation requirements for achieving stringent transgene confinement in rice. To investigate the extent of pollen-mediated crop-to-crop transgene flow, we conducted a field experiment with four plot-size treatments of adjacent GM and nonGM rice ( Oryza sativa ) in China.• Three insect-resistant GM rice ( Bt / CpTI ) and nonGM isogenic lines were used in the study. The hygromycin-resistance transgene ( hpt ) marker was used to screen seeds from the nonGM rice rows at different distance intervals from GM rice plots.• Based on the examination of > 2.1 million germinated seeds, we found a dramatic reduction in transgene frequencies with increasing distance from the GM crop, ranging from c . 0.28% at 0.2 m to < 0.01% at 6.2 m. In addition, different plot size did not significantly affect the frequencies of gene flow.• In conclusion, pollen-mediated crop-to-crop transgene flow in rice can be maintained at negligible levels with short spatial isolation. The model can also be applied to other crops with self-and wind-pollination.

Summary• Crop-to-crop transgene flow will affect seed purity of non-GM rice varieties, leading to unwanted consequences. To assess the maximum probability of transgene outflow in rice ( Oryza sativa ), gene flow experiments were conducted with three cultivation patterns with different mixed-planting proportions of adjacent GM and non-GM rice at two sites in Fujian and Hainan Provinces of China.• Three GM rice lines containing two insect-resistance genes ( Bt / CpTI ) and their non-GM counterparts were used in the experiments to allow natural hybridization to occur. A hygromycin resistance gene was used as a selective marker for identifying hybrids.• Based on the examination of > 645 700 geminated seeds, the result showed low frequencies (0.05 -0.79%) of transgene flow from GM to non-GM rice at close spacing, although with significant variation among mixed-planting proportions.• It is concluded that rice transgene flow will occur at a very low frequency (< 1.0%), even if the GM rice is planted at close spacing with non-GM rice, and high densities of GM rice cultivated in the neighborhood of non-GM rice will increase the probability of outcrossing with the non-GM rice.