Despite the long history of mushroom use, studies examining the genetic function of mushrooms and the development of new varieties via bio-molecular methods are significantly lacking compared to those examining other organisms. However, owing to recent developments, attempts have been made to use a novel gene-editing technique involving CRISPR/Cas9 technology and genetic scissors in mushroom studies. In particular, research is actively being conducted to utilize ribonucleoprotein particles (RNPs) that can be genetically edited with high efficiency without foreign gene insertion for ease of selection. However, RNPs are too large for Cas9 protein to pass through the cell membrane of the protoplasmic reticulum. Furthermore, guide RNA is unstable and can be easily decomposed, which remarkably affects gene editing efficiency. In this study, nanoparticles were used to mitigate the shortcomings of RNP-based gene editing techniques and to obtain transformants stably. We used Lentinula edodes (shiitake mushroom) Sanjo705-13 monokaryon strain, which has been successfully used in previous genome editing experiments. To identify a suitable osmotic buffer for the isolation of protoplast, 0.6 M and 1.2 M sucrose, mannitol, sorbitol, and KCl were treated, respectively. In addition, with various nanoparticle-forming materials, experiments were conducted to confirm genome editing efficiency via the formation of nanoparticles with calcium phosphate (CaP), which can be bound to Cas9 protein without any additional amino acid modification. RNPs/NP complex was successfully formed and protected nuclease activity with nucleotide sequence specificity.

There has been much interest in recycling electronic wastes in order to mitigate environmental problems and to recover the large amount of constituent metals. Silver recovery from electronic waste is extensively studied because of environmental and economic benefits and the use of silver in fabricating nanodevices. Hydrometallurgical processing is often used for silver recovery because it has the advantages of low cost and ease of control. Research on synthesis recovered silver into nanoparticles is needed for application to transistors and solar cells. In this study, silver is selectively recovered from the by-product of electrodes. Silver precursors are prepared using the dissolution characteristics of the leaching solution. In the liquid reduction process, silver nanoparticles are synthesized under various surfactant conditions and then analyzed. The purity of the recovered silver is 99.24%, and the average particle size of the silver nanoparticles is 68 nm.

Lentinula edodes, the popular shiitake mushroom, is one of the most important cultivated edible mushrooms. It is used as a food and for medicinal purposes. Here, we present the 46.1 Mb draft genome of L. edodes, comprising 13,028 predicted gene models. The genome assembly consists of 31 scaffolds. Gene annotation provides key information about various signaling pathways and secondary metabolites. This genomic information should help establish the molecular genetic markers for MAS/MAB and increase our understanding of the genome structure and function.

Mitogen-activated protein kinase (MAPK) signaling cascades play critical roles in various cellular events including abiotic/biotic stress responses, innate immunity, hormone signaling and cell specificity in plants. The MAPK-mediated stress and ethylene signaling are recently known to be involved in nitogen-fixing symbiotic interactions; however, the biological role of MAPK for nodule development in legume plants is largely unknown. We here elucidated that MtMKK5-MtMPK3/6 cascade negatively regulate the nitrogen fixing nodule formation in Medicago truncatula. MtMKK5, an ortholog of SIMKK, overexpression significantly reduces the nodule formation in M. truncatula roots. MtMKK5 directly activates MtMPK3/6 by phosphorylation on the TEY motif within the activation loop in the cytoplasm, which might link to EFD as a negative regulator for nodule formation. EFD has a putative MAPK phosphorylation Thr residue and could be a target of the activated MtMPK3/6 in the nucleus. Consistently, a MAPK specific inhibitor U0126 enhances nodule formation and confers similar nodule phenotypes to the efd-1 mutant such as lower proliferation and differentiation to symbiotic tissues. Our works thus reveal a key negative signaling module mediated by MtMKK5-MtMPK3/6-EFD for symbiotic nitrogen fixing nodule organogenesis.

Seed germination and the establishment of young seedlings are critical phases in the plant’s life cycle. To control these processes, plants have evolved diverse hormonal signaling networks in which brassinosteroids (BRs) attenuate abscisic acid (ABA) responses; however, the underlying regulatory mechanism remains elusive. Here, we reveal that epigenetic silencing of the ABA signaling regulator ABI3 via the BR-related transcription factor BES1 is essential for the inhibitory effect of BRs on ABA signaling during early seedling development. BR-activated BES1 forms a transcriptional repressor complex with TPL via its EAR motif that recruits the histone deacetylase HDA19. This facilitates the histone H3-mediated deacetylation of ABI3 chromatin, leading to the suppression of ABI3 and its downstream target ABI5, which results in reduced ABA sensitivity. We propose that the BR-activated BES1-TPL-HDA19 repressor complex controls epigenetic silencing of ABI3 and thereby suppresses the ABA response during early seedling development.

Mitogen-activated protein kinase (MAPK) signaling cascades play critical roles in various cellular events including abiotic/biotic stress responses, innate immunity, hormone signaling and cell specificity in plants. The MAPK-mediated stress and ethylene signaling are recently known to be involved in nitogen-fixing symbiotic interactions; however, the biological role of MAPK for nodule development in legume plants is largely unknown. We here elucidated that MtMKK5-MtMPK3/6 cascade negatively regulate the nitrogen fixing nodule formation in Medicago truncatula. MtMKK5, an ortholog of SIMKK, overexpression significantly reduces the nodule formation in M. truncatula roots. MtMKK5 directly activates MtMPK3/6 by phosphorylation on the TEY motif within the activation loop in the cytoplasm, which might link to EFD as a negative regulator for nodule formation. EFD has a putative MAPK phosphorylation Thr residue and could be a target of the activated MtMPK3/6 in the nucleus. Consistently, a MAPK specific inhibitor U0126 enhances nodule formation and confers similar nodule phenotypes to the efd-1 mutant such as lower proliferation and differentiation to symbiotic tissues. Our works thus reveal a key negative signaling module mediated by MtMKK5-MtMPK3/6-EFD for symbiotic nitrogen fixing nodule organogenesis.