Molecular breeding of water lily: engineering cold stress tolerance into tropical water lily

Water lilies(order Nymphaeales)are rich in both economic and cultural values.They grow into aquatic herbs,and are divided into two ecological types:tropical and hardy.Although tropical water lilies have more ornamental and medicinal values compared to the hardy water lily,the study and utilization of tropical water lilies in both landscaping and pharmaceutical use is greatly hindered due to their limited planting area.Tropical water lilies cannot survive the winter in areas beyond 24.3°N latitude.Here,the transgenic pipeline through the pollen-tube pathway was generated for water lily for the first time.To improve cold stress tolerance of tropical water lilies,a gene encoding choline oxidase(CodA)driven by a cold stress-inducible promoter was transformed into a tropical water lily through the pollen-tube transformation.Six independent transgenic lines were tested for survival rate during two winter seasons from 2015 to 2017 in Hangzhou(30.3°N latitude).PCR and southern blot detection revealed that the CodA gene had been integrated into the genome.Reverse transcription PCR showed that CodA gene was induced after cold stress treatment,and further quantitative real-time PCR revealed different expressions among six 4 lines and line 3 had the highest expression.Multiple physiological experiments showed that after cold stress treatment,both the conductivity and malondialdehyde(MDA)levels from transgenic plants were significantly lower than those of non-transgenic plants,whereas the content of betaine and the activity of superoxide dismutase,catalase,and peroxidase were higher than those from non-transgenic plants.These results suggest that expression of exogenous CodA gene significantly improved the cold stress tolerance of tropical water lilies through a wide range of physiological alterations.Our results currently expanded a six-latitude cultivating area of the tropical water lilies.These results not only illuminate the bright future for water lily breeding but will also facilitate the functional genomic studies.

Lignin biosynthesis and accumulation in response to abiotic stresses in woody plants

Woody plants have to experience various abiotic stresses due to their immobility and perennial characteristics.However,woody plants have evolved a series of specific regulation pathways in physiological and molecular mechanisms to deal with adverse environments.Compared with herbaceous plants,perennial woody plants have the advantages of developed roots and hard stems,and increased secondary xylem,which can strengthen the vascular system of the plants.The lignification process involves the lignin deposition on the cell wall by oxidation and polymerization of lignin monomer,which plays an important role in abiotic stress tolerance.This review focuses on recent progress in the biosynthesis,content,and accumulation of lignin in response to various abiotic stresses in plants.The role of transcription factors is also discussed in regulating lignin biosynthesis to enhance abiotic stress tolerance via changing cell wall lignification.Although woody plants shared similar lignin biosynthesis mechanisms with herbaceous plants,the temporal and spatial expression and stress response profiles of lignin biosynthetic genes provide the basis for the differences in stress tolerance of various species.An in-depth understanding of the role of lignin in the abiotic stress tolerance of woody plants will lay the foundation for the next step in tree resistance breeding through genetic engineering.

毛竹不同截短U3启动子的克隆及表达分析

具有明确转录起始位点的U3和U6启动子是CRISPR/Cas9技术中驱动sgRNA转录的重要元件。从毛竹(Phyllostachys edulis)中克隆了2个PeU3启动子,均进行了3个不同长度的截短,长度分别为550、397和149 bp及561、392和152 bp;并分别构建6个启动子驱动的GUS及LUC植物表达载体,再利用农杆菌(Agrobacterium tumefaciens)介导法分别转化麻竹(Dendrocalamus latiflorus)愈伤组织和烟草(Nicotiana benthamiana)叶片。结果显示,这些PeU3启动子总体都具有转录活性,不同PeU3启动子以及同一PeU3启动子不同截短时其转录活性不同,其中长度为397 bp的PeU3-1-2pro启动子活性最强,可为构建竹子CRISPR/Cas9基因组编辑体系提供更多理想的内源启动子。

Plant Biosystems Design Research Roadmap 1.0

Human life intimately depends on plants for food,biomaterials,health,energy,and a sustainable environment.Various plants have been genetically improved mostly through breeding,along with limited modification via genetic engineering,yet they are still not able to meet the ever-increasing needs,in terms of both quantity and quality,resulting from the rapid increase in world population and expected standards of living.A step change that may address these challenges would be to expand the potential of plants using biosystems design approaches.This represents a shift in plant science research from relatively simple trial-and-error approaches to innovative strategies based on predictive models of biological systems.Plant biosystems design seeks to accelerate plant genetic improvement using genome editing and genetic circuit engineering or create novel plant systems through de novo synthesis of plant genomes.From this perspective,we present a comprehensive roadmap of plant biosystems design covering theories,principles,and technical methods,along with potential applications in basic and applied plant biology research.We highlight current challenges,future opportunities,and research priorities,along with a framework for international collaboration,towards rapid advancement of this emerging interdisciplinary area of research.Finally,we discuss the importance of social responsibility in utilizing plant biosystems design and suggest strategies for improving public perception,trust,and acceptance.