Biological, environmental and socioeconomic threats to citrus lime production

Limes as a fruit crop are of great economic importance, key to Asian and South American cuisines and cultivated in nearlyall tropical and subtropical regions of the world. Demand for limes is increasing, driven by World Health Organizationrecommendations. Pests and pathogens have significantly reduced global productivity, while changes in agronomictechniques aim to alleviate this stress. We present here a holistic examination of the major biotic (pests and pathogens) andabiotic (environment and socioeconomic) factors that presently limit global production of lime. The major producers oflimes are India, China and Mexico, while loss of lime production in the United States from 2006 has led many countries inthe Western Hemisphere (Mexico, Costa Rica and Brazil) to export primarily to the USA. The most widespread inver-tebrate pests of lime areToxoptera citricidaandScirtothrips citri. Another insect,Diaphorina citri, vectors both Huan-glongbing (HLB) and Witches Broom of Lime, which are particularly destructive diseases. Developing agronomictechniques focus on production of resistant and pathogen-free planting materials and control of insect vectors. HLB infectscitrus in nearly all growing regions, and has been particularly devastating in Asian citrus. Meanwhile,Citrus tristeza virushas infected over 100 million citrus trees, mainly in the Americas and Mediterranean. Currently, Witches Broom Disease ofLime is localised to the Middle East, but recently it has been detected in South America. The range of its vectors (D. citriandHishimonus phycitis) further raises concerns about the potential spread of this disease. Abiotic threats to limeproduction are also a significant concern; key areas of lime production such as Mexico, India and the Middle East sufferfrom increasing water stress and high soil salinity, which combined with invasive pests and pathogens, may eliminate limeproduction in these areas. To ensure future security in lime production, policy makers, researchers and growers will need toexamine the potential of more resistant lime cultivars and establish novel areas of cultivation

Heteromeric Solute Carriers: Function, Structure, Pathology and Pharmacology

Solute carriers form one of three major superfamilies of membrane transporters in humans, and include uniporters, exchangers and symporters. Following several decades of molecular characterisation, multiple solute carriers that form obligatory heteromers with unrelated subunits are emerging as a distinctive principle of membrane transporter assembly. Here we comprehensively review experimentally established heteromeric solute carriers: SLC3-SLC7 amino acid exchangers, SLC16 monocarboxylate/H+ symporters and basigin/embigin, SLC4A1 (AE1) and glycophorin A exchanger, SLC51 heteromer Ost α-Ost β uniporter, and SLC6 heteromeric symporters. The review covers the history of the heteromer discovery, transporter physiology, structure, disease associations and pharmacology - all with a focus on the heteromeric assembly. The cellular locations, requirements for complex formation, and the functional role of dimerization are extensively detailed, including analysis of the first complete heteromer structures, the SLC7-SLC3 family transporters LAT1-4F2hc, b0,+AT-rBAT and the SLC6 family heteromer B0AT1-ACE2. We present a systematic analysis of the structural and functional aspects of heteromeric solute carriers and conclude with common principles of their functional roles and structural architecture