Unravelling enzymatic discoloration in potato through a combined approach of candidate genes, QTL, and expression analysis

Enzymatic discoloration (ED) of potato tubers was investigated in an attempt to unravel the underlying genetic factors. Both enzyme and substrate concentration have been reported to influence the degree of discoloration and as such this trait can be regarded as polygenic. The diploid mapping population C × E, consisting of 249 individuals, was assayed for the degree of ED and levels of chlorogenic acid and tyrosine. Using this data, Quantitative Trait Locus (QTL) analysis was performed. Three QTLs for ED have been found on parental chromosomes C3, C8, E1, and E8. For chlorogenic acid a QTL has been identified on C2 and for tyrosine levels, a QTL has been detected on C8. None of the QTLs overlap, indicating the absence of genetic correlations between these components underlying ED, in contrast to earlier reports in literature. An obvious candidate gene for the QTL for ED on Chromosome 8 is polyphenol oxidase (PPO), which was previously mapped on chromosome 8. With gene-specific primers for PPO gene POT32 a CAPS marker was developed. Three different alleles (POT32-1, -2, and -3) could be discriminated. The segregating POT32 alleles were used to map the POT32 CAPS marker and QTL analysis was redone, showing that POT32 coincides with the QTL peak. A clear correlation between allele combinations and degree of discoloration was observed. In addition, analysis of POT32 gene expression in a subset of genotypes indicated a correlation between the level of gene expression and allele composition. On average, genotypes having two copies of allele 1 had both the highest degree of discoloration as well as the highest level of POT32 gene expression

Molecular and Physiological Properties Associated with Zebra Complex Disease in Potatoes and Its Relation with Candidatus Liberibacter Contents in Psyllid Vectors

Zebra complex (ZC) disease on potatoes is associated with Candidatus Liberibacter solanacearum (CLs), an α-proteobacterium that resides in the plant phloem and is transmitted by the potato psyllid Bactericera cockerelli (Šulc). The name ZC originates from the brown striping in fried chips of infected tubers, but the whole plants also exhibit a variety of morphological features and symptoms for which the physiological or molecular basis are not understood. We determined that compared to healthy plants, stems of ZC-plants accumulate starch and more than three-fold total protein, including gene expression regulatory factors (e.g. cyclophilin) and tuber storage proteins (e.g., patatins), indicating that ZC-affected stems are reprogrammed to exhibit tuber-like physiological properties. Furthermore, the total phenolic content in ZC potato stems was elevated two-fold, and amounts of polyphenol oxidase enzyme were also high, both serving to explain the ZC-hallmark rapid brown discoloration of air-exposed damaged tissue. Newly developed quantitative and/or conventional PCR demonstrated that the percentage of psyllids in laboratory colonies containing detectable levels of CLs and its titer could fluctuate over time with effects on colony prolificacy, but presumed reproduction-associated primary endosymbiont levels remained stable. Potato plants exposed in the laboratory to psyllid populations with relatively low-CLs content survived while exposure of plants to high-CLs psyllids rapidly culminated in a lethal collapse. In conclusion, we identified plant physiological biomarkers associated with the presence of ZC and/or CLs in the vegetative potato plant tissue and determined that the titer of CLs in the psyllid population directly affects the rate of disease development in plants

Wheelchair as semiotic: space governance of the American handicapped parking space

The wheelchair has become a stereotypical symbol of physical disability. The image may appear as a picture, as on parking signs with a blue background and a white figure sitting in a wheelchair, or in reality when one sees an actual person sitting in one. Both images are useful in characterising the governance of the handicapped parking space, a field that presents a unique case study in the interpretation and enforcement of law. The parking space is legally reserved for vehicles marked by the Blue Wheelchair which hangs as a tag from the rearview mirror or on the licence plate; but at the same time it is socially reserved for vehicles driven by a person who is dependent upon an actual wheelchair. Law enforces this space formally by ticketing and/or towing violating vehicles. Society enforces this space informally through the disciplining gaze of onlookers. Legal enforcement is based upon the presence of the Blue Wheelchair symbol as it matches the sign that towers above the reserved spot. Social enforcement judges and disciplines through the qualifying observation of visible disability in the form of a wheelchair. However, what happens when a Blue Wheelchair symbol is present, but an actual wheelchair is absent? Which source of legitimacy is treated as the more authoritative

Beyond Secular Liberalism: Islamic Activism in Lebanon

While many scholars have focused on questions of non- or post-secularity vis-à-vis the “modern nation state,” fewer have asked what kind of decolonial redemption is possible under global neoliberal capitalism today. This is precisely the question I seek to address in this article by analyzing the contemporary ideas and practices of the charities affiliated with what is collectively known as the Islamic resistance movement in Lebanon. Based on almost two and a half years of ethnographic fieldwork in Lebanon on the charities affiliated with the three main Shi'i activist movements loosely comprising the Islamic resistance movement—Hizbullah, al-Mabarrat Association, and Imam al-Sadr Foundation—I describe how all three are selectively resisting some aspects of secular liberalism while accepting others. However, by employing a decentered approach to my analysis, I also highlight how their negotiation with secular liberalism is on their own terms, thus ultimately presenting a challenge to Western hegemony. These charities employ multiple conceptions of rationality, including religious rationality and a range of liberal and even neoliberal economic principles; but by centering their project on faith, Islam, and resistance, these charities reproduce what I call “resistance subjectivities,” allowing the Islamic resistance movement to present unique challenges to Western secular modernity

Inventing terrorists: the nexus of intelligence and Islamophobia

The transatlantic Islamophobia industry, emboldened by US intelligence efforts to entrap Muslims, appears to have helped to increase permissible levels of Islamophobia across the US, as illustrated by the fiery anti-Muslim rhetoric during the 2016 presidential campaign. In this article, I first look at five key leaders of the Islamophobia industry who also claim to be “terrorism experts” and have links to US and Israeli intelligence. I then describe US law enforcement’s mass surveillance of Muslims and its invention of terrorists, including a map of the “successful terrorist prosecutions” claimed by the US Department of Justice, most of which were tried only as criminal cases. Finally, I explore in-depth the case against the Holy Land Foundation, a Muslim charity based in Texas that was run by Palestinian-Americans and targeted by both the state and the Islamophobia industry for its dubious links to “terrorism”, helping to legitimate the Bush W. Administration’s “War on Terror”. I argue that this nexus of intelligence and Islamophobia has empowered anti-Muslim voices that were formerly marginal