Selective plant growth using D-amino acids

Selectable marker genes are essential for the efficient selection of transgenic plants. Heterologous genes used as markers typically encode enzymes that neutralize a toxic compound, allowing for positive selection of plants containing the marker. We report on the efficacy of a novel marker gene system that exploits the varying phytotoxicity of D-amino acids and their oxidative deamination products. Our investigation of a putative DAAO gene from Schizosaccharomyces pombe reveals sufficient oxidative deaminase activity to confer D-alanine and D-serine tolerance to transgenic Arabidopsis thaliana plants carrying the heterologous spDAAO gene. We have demonstrated that the spDAAO, when used in conjunction with D-alanine, allows for the positive selection of primary transformants at levels comparable to hygromycin. Additionally, our selection scheme carries the potential for negative selection in the presence of different selection substrates, such as D-valine or D-isoleucine. This attribute, known as conditional selection would provide particular utility to applications involving site-specific recombinase mediated marker gene removal.M.S.Includes bibliographical references (p. 42-46)

Novel Approaches for Sustainable Horticultural Crop Production: Advances and Prospects

Reduction of plant growth, yield and quality due to diverse environmental constrains along with climate change significantly limit the sustainable production of horticultural crops. In this review, we highlight the prospective impacts that are positive challenges for the application of beneficial microbial endophytes, nanomaterials (NMs), exogenous phytohormones strigolactones (SLs) and new breeding techniques (CRISPR), as well as controlled environment horticulture (CEH) using artificial light in sustainable production of horticultural crops. The benefits of such applications are often evaluated by measuring their impact on the metabolic, morphological and biochemical parameters of a variety of cultures, which typically results in higher yields with efficient use of resources when applied in greenhouse or field conditions. Endophytic microbes that promote plant growth play a key role in the adapting of plants to habitat, thereby improving their yield and prolonging their protection from biotic and abiotic stresses. Focusing on quality control, we considered the effects of the applications of microbial endophytes, a novel class of phytohormones SLs, as well as NMs and CEH using artificial light on horticultural commodities. In addition, the genomic editing of plants using CRISPR, including its role in modulating gene expression/transcription factors in improving crop production and tolerance, was also reviewed