Conventional antibiotic therapies are becoming less efficient due to the emergence of antibiotic-resistant bacterial strains. Development of novel antibacterial material to effectively inhibit or kill bacteria is crucial. A graphene-based photothermal agent, magnetic reduced graphene oxide functionalized with glutaraldehyde (MRGOGA), was synthesized for efficient capture and effective killing of both gram-positive Staphylococcus aureus ( S. aureus ) and gram-negative Escherichia coli ( E. coli ) bacteria upon near-infrared (NIR) laser irradiation. In the present work, we took advantage of the excellent photothermal properties of reduced graphene oxide upon NIR laser irradiation and glutaraldehyde as an efficient capturing agent toward both bacteria. Its magnetic characteristic allows bacteria to be readily trapped in a small volume by the external magnet. The synergetic effects increase the heating extent by MRGOGA upon NIR laser irradiation and the killing of the captured bacteria. The survival rate and membrane integrity assay demonstrate that 80 ppm MRGOGA solution provided rapid and effective killing of up to 99% of both gram-positive and gram-negative bacteria in 10 min upon NIR laser irradiation under batch operation mode. Graphene demonstrated better photothermal antibacterial efficiency than carbon nanotubes. Furthermore, a microfluidic chip system under continuous operation mode demonstrates the reusability of MRGOGA and offers a biocompatible platform for online phothothermal sterilization.

Agrobacterium-mediated transient expression is a powerful analysis platform for diverse plant gene functional studies, but the mechanisms regulating the expression or transformation levels are poorly studied. Previously, we developed a highly efficient and robust Agrobacterium-mediated transient expression system, named AGROBEST, for Arabidopsis seedlings. In this study, we found that AGROBEST could promote the growth of agrobacteria as well as inhibit the host immunity response. When the factor of agrobacterial growth is minimized, maintaining pH at 5.5 with MES buffer was the key to achieving optimal transient expression efficiency. The expression of plant immunity marker genes, FRK1 and NHL10, was suppressed in the pH-buffered medium as compared with non-buffered conditions in Col-0 and an efr-1 mutant lacking the immunity receptor EFR recognizing EF-Tu, a potent pathogen- or microbe-associated molecular pattern (PAMP or MAMP) of A. tumefaciens. Notably, such immune suppression could also occur in Arabidopsis seedlings without Agrobacterium infection. Furthermore, the PAMP-triggered influx of calcium ions was compromised in the pH-buffered medium. We propose that the enhanced transient expression efficiency by stable pH was due to inhibiting calcium ion uptake and subsequently led to suppressing immunity against Agrobacterium.

Aphids are serious pests of agricultural and ornamental plants and important model systems for hemipteran–plant interactions. The long evolutionary history of aphids with their host plants has resulted in a variety of systems that provide insight into the different adaptation strategies of aphids to plants and vice versa. In the past, various plant–aphid interactions have been documented, but lack of functional tools has limited molecular studies on the mechanisms of plant–aphid interactions. Recent technological advances have begun to reveal plant–aphid interactions at the molecular level and to increase our knowledge of the mechanisms of aphid adaptation or specialization to different host plants. In this article, we compile and analyze available information on plant–aphid interactions, discuss the limitations of current knowledge, and argue for new research directions. We advocate for more work that takes advantage of natural systems and recently established molecular techniques to obtain a comprehensive view of plant–aphid interaction mechanisms. Expected final online publication date for the Annual Review of Entomology, Volume 68 is January 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.