Nicotiana benthamiana is an invaluable model plant and biotechnology platform with a ~3 Gb allotetraploid genome. To further improve its usefulness and versatility, we have produced high-quality chromosome-level genome assemblies, coupled with transcriptome, epigenome, microRNA and transposable element datasets, for the ubiquitously used LAB strain and a related wild accession, QLD. In addition, single nucleotide polymorphism maps have been produced for a further two laboratory strains and four wild accessions. Despite the loss of five chromosomes from the ancestral tetraploid, expansion of intergenic regions, widespread segmental allopolyploidy, advanced diploidization and evidence of recent bursts of Copia pseudovirus (Copia) mobility not seen in other Nicotiana genomes, the two subgenomes of N. benthamiana show large regions of synteny across the Solanaceae. LAB and QLD have many genetic, metabolic and phenotypic differences, including disparate RNA interference responses, but are highly interfertile and amenable to genome editing and both transient and stable transformation. The LAB/QLD combination has the potential to be as useful as the Columbia-0/Landsberg errecta partnership, utilized from the early pioneering days of Arabidopsis genomics to today.

Plant viruses are commonly vectored by flying or crawling animals, such as aphids and beetles, and cause serious losses in major agricultural and horticultural crops. Controlling virus spread is often achieved by minimizing a crop’s exposure to the vector, or by reducing vector numbers with compounds such as insecticides. A major, but less obvious, factor not controlled by these measures is Homo sapiens. Here, we discuss the inconvenient truth of how humans have become superspreaders of plant viruses on both a local and a global scale.

グルタミン酸脱炭酸酵素（GAD）活性を利用したたくあん漬けのγ-アミノ酪酸（GABA）含量の変化について検討を行った．新鮮ダイコンのGABA含有量0.28±0.01mg/g乾燥重（DW）に対して，日干しまたは塩押しといった脱水処理により4.93∼9.07mg/g DWまで増大した．グルタミン酸（Glu）は5.72±0.23mg/g DWから0.59∼0.85mg/g DWまで減少した．GAD活性は新鮮ダイコンで最も高く，脱水·塩蔵処理にともない顕著に低下した．食塩と同時に0.1∼0.5%のグルタミン酸ナトリウム（MSG）を添加することで，さらに1.2∼3倍まで増大させることができた．MSG添加した塩蔵ダイコンの上がり水に，経時的なGluの低下とGABAの増大が認められた．微生物により変換されたGABAが塩蔵ダイコンに移行することが示唆された．塩蔵ダイコンの色は，無添加ダイコンでは淡黄色を保持していたが，MSG添加したダイコンは，塩蔵2ヶ月を超えると，くすんだ灰色に変色した．これらの結果から，MSGの添加は塩蔵ダイコンのGABAを富化させることはできるが，色の変化により塩蔵による保存寿命を短縮させることが明らかになった．

Since its discovery, RNA interference (RNAi, also known as gene silencing) has been a key tool to downregulate gene expression in plants for a range of applications, including protection against viruses. Many of these applications require the silencing of multiple genes concomitantly. Multi‐gene silencing, however, can be difficult to achieve owing to challenges in generating single RNAi constructs targeting unrelated genes or due to molecular instability linked to those constructs. Here, we show that microRNA‐induced gene silencing (MIGS) can overcome many of these limitations and can be an important tool for multi‐gene silencing in plants. We demonstrate how MIGS targeting several genes enhances the RNAi‐based inhibition of one or more viruses. We also define several key features for optimising the use of MIGS in plants, including modular design, effective targeting length and phased first‐base composition.