Plant Protection by Benzoxazinoids—Recent Insights into Biosynthesis and Function

Benzoxazinoids (BXs) are secondary metabolites present in many Poaceae including the major crops maize, wheat, and rye. In contrast to other potentially toxic secondary metabolites, BXs have not been targets of counter selection during breeding and the effect of BXs on insects, microbes, and neighbouring plants has been recognised. A broad knowledge about the mode of action and metabolisation in target organisms including herbivorous insects, aphids, and plants has been gathered in the last decades. BX biosynthesis has been elucidated on a molecular level in crop cereals. Recent advances, mainly made by investigations in maize, uncovered a significant diversity in the composition of BXs within one species. The pattern can be specific for single plant lines and dynamic changes triggered by biotic and abiotic stresses were observed. Single BXs might be toxic, repelling, attractive, and even growth-promoting for insects, depending on the particular species. BXs delivered into the soil influence plant and microbial communities. Furthermore, BXs can possibly be used as signalling molecules within the plant. In this review we intend to give an overview of the current data on the biosynthesis, structure, and function of BXs, beyond their characterisation as mere phytotoxins

Arabidopsis

<i>2.1. Transgenic Arabidopsis synthesises benzoxazinoids</i> <p> Previous experiments to transfer GDIBOA biosynthesis to Arabidopsis by first generating individual <i>Bx</i> -gene transgenics and consecutive merging by crossing were not successful. Since in this approach the six essential genes of the pathway (Fig. 1) were driven by the cauliflower mosaic virus 35S promoter (<i>p35S</i>) gene silencing caused by the multiple use of the strong promoter might have occurred (Mlotshwa et al., 2010). To promote gene expression we employed Arabidopsis promoters and changed the codon usage of the G/C-rich maize genes to fit to the A/T preference of Arabidopsis. For the choice of promoters the criteria were moderate to high expression in rosette leaves and low expression in flower organs, the latter based on the finding that joining of <i>Bx1</i> and <i>Bx2</i> both expressed as p35 S-constructs generated female and male sterile plants (Supplemental Figure S12B). According to the Arabidopsis eFP browser developmental map (Winter et al., 2007) P450 genes of glucosinolate biosynthesis, <i>Cyp71B7, Cyp79B2</i>, <i>Cyp83A1</i>, and <i>Cyp83B1 (SUPERROOT2)</i> displayed a suitable expression pattern and the cDNA of the <i>Bx-</i> genes were integrated between the intrinsic start and stop codons (Supplemental Figure S1). To reduce the number of required transformation events, the genes <i>Bx2</i> to <i>Bx5</i> were merged in one T-DNA and the resulting transgenics were termed Cluster (the nomenclature of the transgenics is summarised Table 1). As another precautionary measure to guarantee efficiency of the maize P450s we isolated the maize gene model Zm00001d026483 that is annotated as P450 oxidoreductase (named <i>ZmPor 2</i> in the following). According to the maize eFP browser (Stelpflug et al., 2016; Winter et al., 2007), <i>ZmPor2</i> is highly expressed in seedlings. In the transgenics the gene is driven by <i>p35S</i>. The enzymatic activity of P450s in the transgenics was verified with isolated microsomes (Table 2A). For the substrates ION, and HION consecutive reactions yielding HBOA and DIBOA, respectively were detected (Table 2A). By crossing and selfing we obtained transgenic plants that feature in addition to the <i>Cluster</i> genes the UDPG: DI(M) BOA-glucosyltransferase <i>Bx8</i> and <i>ZmPor2</i>, each transgene homozygously (Cluster+, Table 1). To complete the pathway Cluster + plants were crossed with transgenics harbouring <i>Bx1</i> driven by promoters conferring different levels of expression, the strong promoters <i>p35S</i> and <i>pSUR2</i> and the weak promoter <i>pNos</i> (Supplemental Figure S2A). We could verify GDIBOA biosynthesis in Arabidopsis when <i>Bx1</i> was driven by <i>pSUR2</i> or <i>p35S</i>. Quantification by LC-MS revealed concentrations of 3.7±0.7 nmol GDIBOA/g DW (Table 3) for <i>p35S:: Bx1Cluster</i> +(Bx1C+) and <i>pSUR2::Bx1Cluster</i> +plants. The result shows that high levels of BX1 are required to initiate BX biosynthesis. The concentrations achieved in the transgenics however are far below the level reached in grasses (e.g. up to 20 000 nmol/g DW in rye leaves, Copaja et al., 2006; Rice et al., 2005) and also below the effective concentration for defence (1 μmol/g FW; Bravo et al., 1997; Bravo and Lazo, 1996; Campos et al., 1989; Long et al., 1975).</p>Published as part of <i>Abramov, Aleksej, Hoffmann, Thomas, Stark, Timo D., Zheng, Linlin, Lenk, Stefan, Hammerl, Richard, Lanzl, Tobias, Dawid, Corinna, Schon, Chris-Carolin, Schwab, Wilfried, Gierl, Alfons & Frey, Monika, 2021, Engineering of benzoxazinoid biosynthesis in Arabidopsis thaliana: Metabolic and physiological challenges, pp. 1-15 in Phytochemistry (112947) (112947) 192</i> on page 3, DOI: 10.1016/j.phytochem.2021.112947, <a href="http://zenodo.org/record/10126052">http://zenodo.org/record/10126052</a&gt

Anthologie de la musique russe

Titre uniforme : [Tri pesenki iz vospominanij ûnoseskih godov. W 23]Titre uniforme : [Pribaoutki. W 26]Titre uniforme : [Piano-rag-music. W 44]Titre uniforme : [Pesn' o lesah. Op. 81]Titre uniforme : [Sneguročka]. ExtraitTitre uniforme : [Aleksandr Nevskij. Op. 78 (Cantate)]Titre uniforme : [Hovanscina]. ExtraitTitre uniforme : [Boris Godunov]. ExtraitTitre uniforme : [Kola Brûn'on, master iz Klamsi. Op. 24. Ouverture]Titre uniforme : [Gaânè]. ExtraitTitre uniforme : [Kamarinskaâ]Titre uniforme : [Rusalka]. Extr.Titre uniforme : [Sneguročka. ČS 15]Titre uniforme : [Už gasli v komnatah ogni. ČS 297]Titre uniforme : [Nocturnes. Violoncelle, orchestre. ČS 349. Ré mineur]Titre uniforme : [Orleanskaâ deva. ČS 6]. ExtraitTitre uniforme : [Knâzʹ Igorʹ]. ExtraitComprend : La steppe toujours la steppe / Choeur populaire d'Etat de l'URSS - Le Dimanche j'allai à la fête / Quintette vocal des Soeurs Fedorov - Au bord du fleuve / Choeur populaire d'Etat de l'URSS - J'irai danser sur le pré / Quintette vocal des Soeurs Fedorov - Chanson triste / Quintette vocal des soeurs Fedorov - Chemins / Novikov ; Mark Reizen, choeurs et ensemble d'instruments populaire Dir. Alexandrov - Le tombeau d'Askold / Verstovski ; G. Nelepp, Choeur et orchestre de la Radio d'Etat de l'URSS, dir. Smirnov - Kamarinskaia / Glinka ; Orchestre du Grand Théâtre de Moscou, dir. N. Golovanov - Je me souviens du doux moment / Glinka ; S. Lemechev, au pianoN. Walter - Marche de Tchernomor / Glinka ; Orchestre du Grand Théâtre de Moscou, dir. K. Kondrachine - Duo comique / Dargomijski ; G. Vinogradov et A. Ivanov, au pianoG. Orentlikler - Roussalka / Dargomijski ; Mark Reizen, Orchestre du Grand Théâtre de Moscou, dir. Nebolsine - Russie / Balakirev ; Orchestre Symphonique de la Radio d'Etat de l'URSS, dir. N. Golovanov - Le pouvoir hostile / Serov ; N. Stchegolkov, choeurs et Orchestre du Grand Théâtre de Moscou, dir. Kondrachine - Boris Godounov / Moussorgski ; G. Nelepp, I. Kozlovski, solistes, choeurs et orchestre du Grand Théâtre de Moscou, dir. N. Golovanov - Khovantchina / Moussorgski (chant de Marfa) ; Z. Doloukhanova, orchestre du Grand Théatre de Moscou, dir. Kondrachine - Snegourotchka / Rimski-Korsakov ; S. Lemechev, Orchestre du Grand Théâtre de Moscou, dir. Melik-Pachaiev et Orchestre de la Radio d'Etat de l'URSS, dir. A. GAUK - Le prince Igor : Choeur et prologue / Borodine ; Choeurs et orchestre du Grand Théâtre de Moscou, dir. Melik-Pachaiev - Le prince Igor : air de Khontchakovna / Borodine ; E. [i. e. V.] Borissenko, choeurs et orchestre du Grand Théâtre de Moscou, dir. Melik-Pachaiev - Huit chants populaires russes / Liadov ; Orchestre Philharmonique de Moscou, dir. K. Kondrachine - Snegourotchka / Tchaikovski ; Choeurs et orchestre de la Radio d'Etat de l'URSS dir. A. Gauk. - Symphonie N ° 1 : 2ème mouvement / Tchaikovski ; Orchestre philharmonique de Moscou, dir. N. Golovanov - La Pucelle d'Orléans : Adieux à Domrémy / Tchaikovski ; E. Borissenko, orchestre du Grand Théâtre de Moscou, dir. Melik-Pachaiev - Déjà les flammes s'éteignaient / Tchaikovski ; Z. Dloukhanova, au pianoB. Kozel - Nocturne / Tchaikovski ; au pianoEmile Guilels - Comme il fait bon / Rachmaninov ; N. Kazantzeva, au pianoA. Bernard - La fiancée du soldat / Rachmaninov ; E. Borissenko, au pianoM. Makarov - Ouverture solennelle / Glazounov ; Orchestre symphonique de la Radio d'Etat de l'URSS, dir. Golovanov - Concerto pour piano : andante / Samuel Feinberg, piano et Orchestre de la Radio d'Etat de l'URSS, dir. A. Gauk - Piano rag-time / Stravinski ; Robert Cornmann, piano - Souvenirs d'enfance / Stravinski ; Basia Rechitzka, Orchestre philharmonique de Paris, dir. R. Cornmann - Pribaoutki / Stravinski ; Basia Rechitzka, orchestre philharmonique de Paris, dir. R. Cornmann - Alexandre Nevski : final / Prokofiev ; Choeurs et orchestre de la Radio d'Etat de l'URSS, dir. S. Samossoud - Cinq pièces pour violon et piano / Prokofiev ; David Oistrakh et V. Yampolski - Concerto pour piano et trompette : 1er mouvement / Chostakovitch ; M. Pinter, K. [i. e. W.] Bauer, orchestre de Radio-Berlin, dir. Gunther Wand - Le chant des forêts, promenade dans les forêts de l'avenir / Chostakovitch ; Kilichevski, choeurs et orchestre symphonique de l'URSS, dir. Mravinski - Gayaneh, l'incendie / Khatchatourian ; Orchestre du Grand Théâtre De Leningrad, dir. M. Khaikine - La veuve de Valence / Khatchatourian ; Orchestre de la Radio d'Etat de l'URSS, dir. Kovaliov - Le meunier, son fils et l'âne / Kabalevski ; G. Abramov, Orchestre de la Radio d'Etat de l'URSS, dir. Knouchevitzki - Colas Breugnon : ouverture / Kabalevski ; Orchestre de la Radio d'Etat de l' URSS, dir. PavermannBnF-Partenariats, Collection sonore - BelieveContient une table des matière