Photosynthesis and metabolite responses of Isatis indigotica Fortune to elevated [CO2]

Climate change is affecting global crop productivity, food quality, and security. However,few studies have addressed the mechanism by which elevated CO_2 may affect the growth of medicinal plants. Isatis indigotica Fortune is a widely used Chinese medicinal herb with multiple pharmacological properties. To investigate the physiological mechanism of I.indigotica response to elevated [CO_2], plants were grown at either ambient [CO_2](385 μmol mol^(-1)) or elevated [CO_2] (590 μmol mol^(-1)) in an open-top chamber (OTC)experimental facility in North China. A significant reduction in transpiration rate (T_r) and stomatal conductance (g_s) and a large increase in water-use efficiency contributed to an increase in net photosynthetic rate (Pn) under elevated [CO_2] 76 days after sowing. Leaf non-photochemical quenching (NPQ) was decreased, so that more energy was used in effective quantum yield of PSII photochemistry (Φ_(PSⅡ)) under elevated [CO_2]. High ΦPSII,meaning high electron transfer efficiency, also increased Pn. The [CO_2]-induced increase in photosynthesis significantly increased biomass by 36.8%. Amounts of metabolic compounds involved in sucrose metabolism, pyrimidine metabolism, flavonoid biosynthesis, and other processes in leaves were reduced under elevated [CO_2]. These results showed that the fertilization effect of elevated [CO_2] is conducive to increasing dry weight but not secondary metabolism in I. indigotica.

我国杂粮种质资源创新研究:现状与展望

该文系统综述了我国杂粮种质资源保存、鉴定评价、创新利用、基因资源挖掘研究现状,以及基础研究存在的问题和挑战,并提出杂粮研究的重点和发展方向。

Multi-omics analyses of 398 foxtail millet accessions reveal genomic regions associated with domestication,metabolite traits,and antiinflammatory effects

Foxtail millet(Setaria italica),which was domesticatedfromthewild speciesgreenfoxtail(Setaria viridis),isa richsource of phytonutrientsfor humans.To evaluate how breeding changed themetabolome offoxtail millet grains,we generated and analyzed the datasets encompassing the genomes,transcriptomes,metabolomes,and anti-inflammatory indices from 398 foxtail millet accessions.We identified hundreds of common variants that influence numerous secondary metabolites.We observed tremendous differences in natural variations of the metabolites and their underlying genetic architectures between distinct sub-groups of foxtail millet.Furthermore,we found that the selection of the gene alleles associated with yellow grains led to altered profiles of metabolites such as carotenoids and endogenous phytohormones.Using CRiSPR-mediated genome editing wevalidated the function of PHYTOENE SYNTHASE1(PSY1)gene in affecting milletgrain colorand quality.Interestingly,our in vitro cell inflammation assays showed that 83 metabolites in millet grains have anti-inflammatory effects.Taken together,ourmulti-omics study illustrates how the breeding history of foxtail millet has shaped its metabolite profile.The datasets we generated in this study also provide important resources for further understanding how millet grain quality is affected by different metabolites,laying the foundations for future millet genetic research and metabolome-assisted improvement.

Foxtail millet:nutritional and eating quality,and prospects for genetic improvement

Foxtail millet is a minor yet important crop in some areas of the world,particularly northern China.It has strong adaptability to abiotic stresses,especially drought,and poor soil.It also has high nutritional value.Foxtail millet is rich in essential amino acids,fatty acids and minerals,and is considered to be one of the most digestible and non-allergenic grains available and has significant importance for human health.Given foxtail millet’s ability to adapt to abiotic stresses associated with climate change,it is more important than ever to develop breeding strategies that facilitate the increasing demand for high quality grain that better satisfies consumers.Here we review research on foxtail millet quality evaluation,appearance,cooking and eating quality at the phenotypic level.We review analysis of the main nutrients in foxtail millet,their relationships and the biochemical and genetic factors affecting their accumulation.In addition,we review past progress in breeding this regionally important crop,outline current status of breeding of foxtail millet,and make suggestions to improve grain quality.

Plant genetic engineering and genetically modified crop breeding: history and current status

This review charts the major developments in the genetic manipulation of plant cells that have taken place since the first gene transfer experiments using Ti plasmids in 1983. Tremendous progress has been made in both our scientific understanding and technological capabilities since the first genetically modified(GM)crops were developed with single gene resistances to herbicides, insects, viruses, and the silencing of undesirable genes. Despite opposition in some parts of the world, the area planted with first generation GM crops has grown from 1.7 Mhm^2 in 1996 to 179.7 Mhm^2 in 2015.The toolkit available for genetic modification has expanded greatly since 1996 and recently Nobel Laureates have called on Greenpeace to end their blanket opposition,and plant scientists have urged that consideration be given to the benefits of GM crops based on actual evidence. It is now possible to use GM to breed new crop cultivars resistant to a much wider range of pests and diseases, and to produce crops better able to adapt to climate change.The advent of new CRISPR-based technologies makes it possible to contemplate a much wider range of improvements based on transfer of new metabolic pathways and traits to improve nutritional quality, with a much greater degree of precision. Use of GM, sometimes in conjunction with other approaches, offers great opportunities for improving food quality, safety, and security in a changing world.