Application of Developmental Regulators for Enhancing Plant Regeneration and Genetic Transformation.

Establishing plant regeneration systems and efficient genetic transformation techniques plays a crucial role in plant functional genomics research and the development of new crop varieties. The inefficient methods of transformation and regeneration of recalcitrant species and the genetic dependence of the transformation process remain major obstacles. With the advancement of plant meristematic tissues and somatic embryogenesis research, several key regulatory genes, collectively known as developmental regulators, have been identified. In the field of plant genetic transformation, the application of developmental regulators has recently garnered significant interest. These regulators play important roles in plant growth and development, and when applied in plant genetic transformation, they can effectively enhance the induction and regeneration capabilities of plant meristematic tissues, thus providing important opportunities for improving genetic transformation efficiency. This review focuses on the introduction of several commonly used developmental regulators. By gaining an in-depth understanding of and applying these developmental regulators, it is possible to further enhance the efficiency and success rate of plant genetic transformation, providing strong support for plant breeding and genetic engineering research.

Facile fabrication and antibacterial properties of chitosan/acrylamide/gold nanocomposite hydrogel incorporated with Chaetomium globosium extracts from Gingko biloba leaves.

Microorganisms are a unique part of our ecosystem because they affect the survival of living organisms. Although pathogenic microorganisms could be detrimental to the plants, animals, and humans, beneficial microbes have provided significant improvement in the growth and development of living organisms. In this study, the fungus Chaetomium globosium was isolated from the medicinal tree Gingko biloba, and then incorporated into a polymerization system to fabricate chitosan/acrylamide/gold (CS/Am/Au) nanocomposite hydrogels. The as-prepared hydrogel displayed increased mechanical strength due to the reinforcement of Au (gold) nanocomposites within the hydrogel matrix. Also, the equilibrium pH responsive swelling rates of the hydrogels gradually increased as the pH increases due to partial acid and basic hydrolysis occurring in the hydrogel as well as formation of hydrogen bond. In addition, the hydrogel demonstrated promising antibacterial activities against selected gram-positive (Staphylococcus epidermidis and Staphylococcus aureus) and gram-negative (Pseudomonas aeruginosa) bacterial strains with an average MIC90 of 0.125 mg/mL at a dosage of 1.0 mg/L. The obtained results are quite promising towards resolving several health challenges and advancing the pharmaceutical industries.

The Metasequoia genome and evolutionary relationships among redwoods.

Redwood trees (Sequoioideae), including Metasequoia glyptostroboides (dawn redwood), Sequoiadendron giganteum (giant sequoia), and Sequoia sempervirens (coast redwood), are threatened and widely recognized iconic tree species. Genomic resources for redwood trees could provide clues to their evolutionary relationships. Here, we report the 8-Gb reference genome of M. glyptostroboides and a comparative analysis with two related species. More than 62% of the M. glyptostroboides genome is composed of repetitive sequences. Clade-specific bursts of long terminal repeat retrotransposons may have contributed to genomic differentiation in the three species. The chromosomal synteny between M. glyptostroboides and S. giganteum is extremely high, whereas there has been significant chromosome reorganization in S. sempervirens. Phylogenetic analysis of marker genes indicates that S. sempervirens is an autopolyploid, and more than 48% of the gene trees are incongruent with the species tree. Results of multiple analyses suggest that incomplete lineage sorting (ILS) rather than hybridization explains the inconsistent phylogeny, indicating that genetic variation among redwoods may be due to random retention of polymorphisms in ancestral populations. Functional analysis of ortholog groups indicates that gene families of ion channels, tannin biosynthesis enzymes, and transcription factors for meristem maintenance have expanded in S. giganteum and S. sempervirens, which is consistent with their extreme height. As a wetland-tolerant species, M. glyptostroboides shows a transcriptional response to flooding stress that is conserved with that of analyzed angiosperm species. Our study offers insights into redwood evolution and adaptation and provides genomic resources to aid in their conservation and management.