scholarly journals De novo indol-3-ylmethyl glucosinolate biosynthesis, and not long-distance transport, contributes to defence of Arabidopsis against powdery mildew

2019 ◽  
Author(s):  
Pascal Hunziker ◽  
Hassan Ghareeb ◽  
Lena Wagenknecht ◽  
Christoph Crocoll ◽  
Barbara Ann Halkier ◽  
...  

AbstractPowdery mildew is a fungal disease that affects a wide range of plants and reduces crop yield worldwide. As obligate biotrophs, powdery mildew fungi manipulate living host cells to suppress defence responses and to obtain nutrients. Members of the plant order Brassicales produce indole glucosinolates that effectively protect them from attack by non-adapted fungi. Indol-3-ylmethyl glucosinolates are constitutively produced in the phloem and transported to epidermal cells for storage. Upon attack, indol-3-ylmethyl glucosinolates are activated by CYP81F2 to provide broad-spectrum defence against fungi. How de novo biosynthesis and transport contribute to defence of powdery mildew-attacked epidermal cells is unknown. Bioassays and glucosinolate analysis indicate that GTR glucosinolate transporters are not involved in antifungal defence. Using quantitative live-cell imaging of fluorophore-tagged markers, we show that accumulation of the glucosinolate biosynthetic enzymes CYP83B1 and SUR1 is induced in epidermal cells attacked by the non-adapted barley powdery mildew Blumeria graminis f.sp. hordei. By contrast, glucosinolate biosynthesis is attenuated during interaction with the virulent powdery mildew Golovinomyces orontii. Interestingly, SUR1 induction is delayed during the Golovinomyces orontii interaction. We conclude that epidermal de novo synthesis of indol-3-ylmethyl glucosinolate contributes to CYP81F2-mediated broad-spectrum antifungal resistance and that adapted powdery mildews may target this process.

2020 ◽  
Vol 43 (6) ◽  
pp. 1571-1583 ◽  
Author(s):  
Pascal Hunziker ◽  
Hassan Ghareeb ◽  
Lena Wagenknecht ◽  
Christoph Crocoll ◽  
Barbara Ann Halkier ◽  
...  

1987 ◽  
Vol 59 (3) ◽  
pp. 231-249
Author(s):  
Hans Thordal-Christensen ◽  
Per L. Gregersen ◽  
Jan B. Andersen ◽  
Viggo Smedegaars-Petersen

Induced local resistance presumably involves the same mechanisms in the plants as resistance elicited during normal plant-pathogen interactions. In many cases resistance elicitors from pathogens have been found to be non-specific, i.e. unrelated to race-cultivar specificity. Thus, existence of specific resistance suppressors has been suggested to make the virulent races able to infect. In other cases specific resistance elicitors have been indicated to exist in a virulent races, by which the race specific resistance may be accomplished. At our Department resistance has been induced in the barley—powdery mildew interaction by use of double inoculation procedures. Both virulent and avirulent races of barley powdery mildew can induce resistance, but avirulent races show an increased resistance induction ability in relation to virulent races from 12 hours after inoculation. In barley plants wheat powdery mildew induced more resistance than barley powdery mildew 1 to 8 hours after inoculation. Induced resistance was mainly localized to the epidermal cells attacked by the inducer, but an effect was also present in the surrounding epidermal cells. The energetic consequences of resistance in barley to barley powdery mildew have been found to be reflected in an increased respiratory rate at the time of infection attempt. Further, these energy costs appeared to reduce grain yield by 7 %. The expression of resistance in barley is thought to involve de novo synthesis mRNAs and proteins, which makes it possible to apply gene technological methods to study induced resistance. Research of this kind is in progress at our Department, which hopefully will give information on the mechanisms of resistance triggering and resistance expression.


Acarologia ◽  
2017 ◽  
Vol 57 (3) ◽  
pp. 693-721
Author(s):  
Tobias Pfingstl

Existing literature on marine associated Ameronothroidea is reviewed and recapitulated. Although these littoral oribatid mites strongly resemble typical terrestrial mites, they have evolved different adaptions of various kinds to the marine littoral environment. In order to cope with intertidal wave action, most species show reduced and compact sensilla as well as sickle-shaped and elongated claws. Complex cerotegument based plastron mechanisms have evolved to allow breathing under flooded conditions and enabling these organisms to survive an average of more than a month completely submerged in saltwater. Behavioural adaptations include aggregations, diurnal and circatidal activity patterns, daily and seasonal migrations and thigmotaxis. Most taxa show no reproductive adaptions to the littoral habitat but some have developed ovoviviparity to protect the offspring and a few also have evolved distinct sexual dimorphism supposed to allow direct mating and secure sperm transfer in this constantly changing environment. Ameronothroid taxa are basically generalized feeders grazing on intertidal algae, lichens and fungi which also serve as microhabitat. Coastal areas all over the globe have been colonized and these mites can be found in a wide range of habitats: e.g. polar shores, rocky coasts, sandy beaches, tropical mangrove forests, brackish river estuaries and salt marshes. The families show a distinct climate related distribution pattern, with the Ameronothridae (Podacaridae included) in polar and cold temperate regions and the Fortuyniidae and Selenoribatidae in subtropical and tropical areas. Long distance transport to remote islands is supposed to be mainly achieved by bird phoresy in Ameronothridae and by dispersal via strong ocean currents in Fortuyniidae and Selenoribatidae. In literature there are basically two contrasting theories explaining the evolutionary invasion of marine associated habitats by ameronothroid mites, one favoring a monophyletic origin and a single land-to-sea transition event and another preferring an independent terrestrial ancestry and accordingly multiple invasions of the marine littoral environment. Recent molecular genetic studies support the latter theory and render the present superfamily of Ameronothroidea a polyphyletic taxon.


Author(s):  
James Cronshaw

Long distance transport in plants takes place in phloem tissue which has characteristic cells, the sieve elements. At maturity these cells have sieve areas in their end walls with specialized perforations. They are associated with companion cells, parenchyma cells, and in some species, with transfer cells. The protoplast of the functioning sieve element contains a high concentration of sugar, and consequently a high hydrostatic pressure, which makes it extremely difficult to fix mature sieve elements for electron microscopical observation without the formation of surge artifacts. Despite many structural studies which have attempted to prevent surge artifacts, several features of mature sieve elements, such as the distribution of P-protein and the nature of the contents of the sieve area pores, remain controversial.


Author(s):  
А.Р. Зарипова ◽  
Л.Р. Нургалиева ◽  
А.В. Тюрин ◽  
И.Р. Минниахметов ◽  
Р.И. Хусаинова

Проведено исследование гена интерферон индуцированного трансмембранного белка 5 (IFITM5) у 99 пациентов с несовершенным остеогенезом (НО) из 86 неродственных семей. НО - клинически и генетически гетерогенное наследственное заболевание соединительной ткани, основное клиническое проявление которого - множественные переломы, начиная с неонатального периода жизни, зачастую приводящие к инвалидизации с детского возраста. К основным клиническим признакам НО относятся голубые склеры, потеря слуха, аномалия дентина, повышенная ломкость костей, нарушения роста и осанки с развитием характерных инвалидизирующих деформаций костей и сопутствующих проблем, включающих дыхательные, неврологические, сердечные, почечные нарушения. НО встречается как у мужчин, так и у женщин. До сих пор не определена степень генетической гетерогенности заболевания. На сегодняшний день известно 20 генов, вовлеченных в патогенез НО, и исследователи разных стран продолжают искать новые гены. В последнее десятилетие стало известно, что аутосомно-рецессивные, аутосомно-доминантные и Х-сцепленные мутации в широком спектре генов, кодирующих белки, которые участвуют в синтезе коллагена I типа, его процессинге, секреции и посттрансляционной модификации, а также в белках, которые регулируют дифференцировку и активность костеобразующих клеток, вызывают НО. Мутации в гене IFITM5, также называемом BRIL (bone-restricted IFITM-like protein), участвующем в формировании остеобластов, приводят к развитию НО типа V. До 5% пациентов имеют НО типа V, который характеризуется образованием гиперпластического каллуса после переломов, кальцификацией межкостной мембраны предплечья и сетчатым рисунком ламелирования, наблюдаемого при гистологическом исследовании кости. В 2012 г. гетерозиготная мутация (c.-14C> T) в 5’-нетранслируемой области (UTR) гена IFITM5 была идентифицирована как основная причина НО V типа. В представленной работе проведен анализ гена IFITM5 и идентифицирована мутация c.-14C>T, возникшая de novo, у одного пациента с НО, которому впоследствии был установлен V тип заболевания. Также выявлены три известных полиморфных варианта: rs57285449; c.80G>C (p.Gly27Ala) и rs2293745; c.187-45C>T и rs755971385 c.279G>A (p.Thr93=) и один ранее не описанный вариант: c.128G>A (p.Ser43Asn) AGC>AAC (S/D), которые не являются патогенными. В статье уделяется внимание особенностям клинических проявлений НО V типа и рекомендуется определение мутации c.-14C>T в гене IFITM5 при подозрении на данную форму заболевания. A study was made of interferon-induced transmembrane protein 5 gene (IFITM5) in 99 patients with osteogenesis imperfecta (OI) from 86 unrelated families and a search for pathogenic gene variants involved in the formation of the disease phenotype. OI is a clinically and genetically heterogeneous hereditary disease of the connective tissue, the main clinical manifestation of which is multiple fractures, starting from the natal period of life, often leading to disability from childhood. The main clinical signs of OI include blue sclera, hearing loss, anomaly of dentin, increased fragility of bones, impaired growth and posture, with the development of characteristic disabling bone deformities and associated problems, including respiratory, neurological, cardiac, and renal disorders. OI occurs in both men and women. The degree of genetic heterogeneity of the disease has not yet been determined. To date, 20 genes are known to be involved in the pathogenesis of OI, and researchers from different countries continue to search for new genes. In the last decade, it has become known that autosomal recessive, autosomal dominant and X-linked mutations in a wide range of genes encoding proteins that are involved in the synthesis of type I collagen, its processing, secretion and post-translational modification, as well as in proteins that regulate the differentiation and activity of bone-forming cells cause OI. Mutations in the IFITM5 gene, also called BRIL (bone-restricted IFITM-like protein), involved in the formation of osteoblasts, lead to the development of OI type V. Up to 5% of patients have OI type V, which is characterized by the formation of a hyperplastic callus after fractures, calcification of the interosseous membrane of the forearm, and a mesh lamellar pattern observed during histological examination of the bone. In 2012, a heterozygous mutation (c.-14C> T) in the 5’-untranslated region (UTR) of the IFITM5 gene was identified as the main cause of OI type V. In the present work, the IFITM5 gene was analyzed and the de novo c.-14C> T mutation was identified in one patient with OI who was subsequently diagnosed with type V of the disease. Three known polymorphic variants were also identified: rs57285449; c.80G> C (p.Gly27Ala) and rs2293745; c.187-45C> T and rs755971385 c.279G> A (p.Thr93 =) and one previously undescribed variant: c.128G> A (p.Ser43Asn) AGC> AAC (S / D), which were not pathogenic. The article focuses on the features of the clinical manifestations of OI type V, and it is recommended to determine the c.-14C> T mutation in the IFITM5 gene if this form of the disease is suspected.


2018 ◽  
Vol 16 (05) ◽  
pp. 362-368 ◽  
Author(s):  
Federica Sullo ◽  
Agata Polizzi ◽  
Stefano Catanzaro ◽  
Selene Mantegna ◽  
Francesco Lacarrubba ◽  
...  

Cerebellotrigeminal dermal (CTD) dysplasia is a rare neurocutaneous disorder characterized by a triad of symptoms: bilateral parieto-occipital alopecia, facial anesthesia in the trigeminal area, and rhombencephalosynapsis (RES), confirmed by cranial magnetic resonance imaging. CTD dysplasia is also known as Gómez-López-Hernández syndrome. So far, only 35 cases have been described with varying symptomatology. The etiology remains unknown. Either spontaneous dominant mutations or de novo chromosomal rearrangements have been proposed as possible explanations. In addition to its clinical triad of RES, parietal alopecia, and trigeminal anesthesia, CTD dysplasia is associated with a wide range of phenotypic and neurodevelopmental abnormalities.Treatment is symptomatic and includes physical rehabilitation, special education, dental care, and ocular protection against self-induced corneal trauma that causes ulcers and, later, corneal opacification. The prognosis is correlated to the mental development, motor handicap, corneal–facial anesthesia, and visual problems. Follow-up on a large number of patients with CTD dysplasia has never been reported and experience is limited to few cases to date. High degree of suspicion in a child presenting with characteristic alopecia and RES has a great importance in diagnosis of this syndrome.


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