application-two-spotted-spider-mite-tetranychus-urticae-for-plant

Application of Two-spotted Spider Mite <em>Tetranychus urticae</em> for Plant-pest Interaction Studies

The two-spotted spider mite, Tetranychus urticae, is a ubiquitous polyphagous arthropod herbivore that feeds on a remarkably broad array of species, with ...

The University of Western Ontario

Instituto de Ciencias de la Vid y el Vino

Axillary meristems form in the leaf axils during post-embryonic development. In order to initiate the genetic dissection of axillary meristem development, we have characterized the late-flowering branchless ecotype of Arabidopsis thaliana (L.) Heynh., Zu-0. The first-formed rosette leaves of Zu-0 plants all initiate axillary meristems, but later-formed leaves of the rosette remain branchless. Alteration in the meristem development is axillary meristem-specific because the shoot apical and floral meristems develop normally. Scanning electron microscopy, histology and RNA in situ analysis with SHOOTMERISTEMLESS ( STM), a marker for meristematic tissues, show that a mound of cells form and STM mRNA accumulates in barren leaf axils, indicating that axillary meristems initiate but arrest in their development prior to organizing a meristem proper. Expression and retention of the STM RNA in barren leaf axils further suggests that STM expression is not sufficient for the establishment of the axillary meristem proper.

Axillary meristem development in the branchless Zu-0 ecotype of Arabidopsis thaliana.

The genetic changes underlying the diversification of plant forms represent a key question in understanding plant macroevolution. To understand the mechanisms leading to novel plant morphologies we investigated the Sy-0 ecotype of Arabidopsis that forms an enlarged basal rosette of leaves, develops aerial rosettes in the axils of cauline leaves, and exhibits inflorescence and floral reversion. Here we show that this heterochronic shift in reproductive development of all shoot meristems requires interaction between dominant alleles at AERIAL ROSETTE 1 (ART1), FRIGIDA (FRI), and FLOWERING LOCUS C (FLC) loci. ART1 is a new flowering gene that maps 14 cM proximal to FLC on chromosome V. ART1 activates FLC expression through a novel flowering pathway that is independent of FRI and independent of the autonomous and vernalization pathways. Synergistic activation of the floral repressor FLC by ART1 and FRI is required for delayed onset of reproductive development of all shoot meristems, leading to the Sy-0 phenotype. These results demonstrate that modulation in flowering-time genes is one of the mechanisms leading to morphological novelties.

The synergistic activation of FLOWERING LOCUS C by FRIGIDA and a new flowering gene AERIAL ROSETTE 1 underlies a novel morphology in Arabidopsis.

Homeodomain proteins are key regulators of patterning during the development of animal and plant body plans. Knotted1-like TALE homeodomain proteins have been found to play important roles in the development of the Arabidopsis shoot apical meristem and are part of a complex regulatory network of protein interactions. We have investigated the possible role of the knotted1-like genes KNAT1, KNAT3, KNAT4, and KNAT5 in Arabidopsis root development. Root growth is indeterminate, and the organ shows distinct zones of cell proliferation, elongation and differentiation along its longitudinal axis. Here we show that KNAT1, KNAT3, KNAT4 and KNAT5 show cell type specific expression patterns in the Arabidopsis root. Moreover, they are expressed in different spatially restricted patterns along the longitudinal root axis and in lateral root primordia. Hormones play an important role in maintenance of root growth, and we have studied their effect on KNAT gene expression. We show that KNAT3 expression is repressed by moderate levels of cytokinin. In addition, we show that the subcellular localization of KNAT3 and KNAT4 is regulated, indicating post-translational control of the activities of these transcription factors. The regulated expression of KNAT1, KNAT3, KNAT4 and KNAT5 within the Arabidopsis root suggests a role for these genes in root development. Our data provide the first systematic survey of KNAT gene expression in the Arabidopsis root.

A map of KNAT gene expression in the Arabidopsis root.

Cellular proteins are extensively degraded during leaf senescence, and this correlates with an up-regulation of protease gene expression, particularly cysteine proteases. The objectives of this work were (i) to detect cysteine proteases associated with senescence of wheat leaves under different conditions and (ii) to find out their subcellular location. Activity labelling of cysteine proteases with the biotinylated inhibitor DCG-04 detected five bands at 27, 36, 39, 42, and 46 kDa in leaves of wheat senescing under continuous darkness. In-gel activity assays showed that these proteases are only active in an acid milieu (pH 4), and their activity increased several-fold in senescing leaves. Fractionation experiments showed that the senescence-associated cysteine proteases of 36, 39, 42, and 46 kDa localize to a vacuolar-enriched fraction. The vacuolar cysteine proteases of 36, 39, and 42 kDa increased in activity in attached flag leaves senescing naturally during post-anthesis, and in attached leaves of plants subjected to a period of water deficit. Thus, the activity of these vacuolar cysteine proteases is associated with developmental (post-anthesis) senescence and with senescence induced by stress factors (i.e. protracted darkness or drought). This suggests that vacuoles are involved in senescence-associated cellular degradation, and that different senescence-inducing factors may converge on a single degradation pathway.

Vacuolar cysteine proteases of wheat (Triticum aestivum L.) are common to leaf senescence induced by different factors.

Chelicerates (scorpions, horseshoe crabs, spiders, mites and ticks) are the second largest group of arthropods and are of immense importance for fundamental and applied science. They occupy a basal phylogenetic position within the phylum Arthropoda, and are of crucial significance for understanding the evolution of various arthropod lineages. Chelicerates are vectors of human diseases, such as ticks, and major agricultural pests, such as spider mites, thus this group is also of importance for both medicine and agriculture. The developmental genetics of chelicerates is poorly understood and a challenge for the future progress for many aspects of chelicerate biology is the development of a model organism for this group. Toward this end, we are developing a chelicerate genetic model: the two-spotted spider mite Tetranychus urticae. T. urticae has the smallest genome of any arthropod determined so far (75 Mbp, 60% of the size of the Drosophila genome), undergoes rapid development and is easy to maintain in the laboratory. These features make T. urticae a promising reference organism for the economically important, poorly studied and species-rich chelicerate lineage.

Mity model: Tetranychus urticae, a candidate for chelicerate model organism.

Differences in life-history strategy are thought to contribute to adaptation to specific environmental conditions. Among life-history traits in plants, flowering time and shoot morphology are particularly important for reproductive success. Even though flowering time and shoot morphology are linked, the evolutionary changes in the genetic circuitry that simultaneously affects both traits remain obscure. Here, we have identified changes in a putative pre-mRNA processing factor, HUA2, as being responsible for the distinct shoot morphology and flowering behavior in Sy-0, a natural strain of Arabidopsis. HUA2 has previously been shown to positively regulate two MADS box genes affecting flowering time (FLOWERING LOCUS C [FLC]) and floral patterning (AGAMOUS [AG]) [1, 2]. We demonstrate that natural changes in HUA2 activity have opposite effects on its known functions, thus having implications for the coordinate control of induction and maintenance of floral fate. The changes in Sy-0 lead to enhanced FLC expression, resulting in an enlarged basal rosette and aerial rosettes, whereas suppression of AG function favors a reversion of floral meristems from determinate to indeterminate development. Natural variation in HUA2 activity thus coordinates changes in two important life-history traits, flowering time and shoot morphology.

HUA2 caused natural variation in shoot morphology of A. thaliana.

MADS-domain transcription factors play pivotal roles in various developmental processes. The lack of simple loss-of-function phenotypes provides impediments to understand the biological function of some of the MADS-box transcription factors. Here we have characterized the potential role of the Arabidopsis thaliana AGAMOUS-LIKE6 (AGL6) gene by fusing full-length coding sequence with transcriptional activator and repressor domains and suggest a role for AGL6 in lateral organ development and flowering. Upon photoperiodic induction of flowering, AGL6 becomes expressed in abaxial and proximal regions of cauline leaf primordia, as well as the cryptic bracts subtending flowers. In developing flowers, AGL6 is detected in the proximal regions of all floral organs and in developing ovules. Converting AGL6 into a strong activator through fusion to the VP16 domain triggers bract outgrowth, implicating AGL6 in the development of bractless flowers in Arabidopsis. In addition, ectopic reproductive structures form on both bracts and flowers in gAGL6::VP16 transgenic plants, which is dependent on B and C class homeotic genes, but independent of LEAFY. Overexpression of both AGL6 and its transcriptional repressor form, AGL6::EAR, causes precocious flowering and terminal flower formation, suggesting that AGL6 suppresses the function of a floral repressor.

Control of lateral organ development and flowering time by the Arabidopsis thaliana MADS-box Gene AGAMOUS-LIKE6.

Tandemly arrayed genes that belong to gene families characterize genomes of many organisms. Gene duplication and subsequent relaxation of selection can lead to the establishment of paralogous cluster members that may evolve along different trajectories. Here, we report on the structural variation in MADS AFFECTING FLOWERING 2 (MAF2) gene, one member of the tandemly duplicated cluster of MADS-box-containing transcription factors in Arabidopsis thaliana. The altered gene structure at the MAF2 locus is present as a moderate-frequency polymorphism in Arabidopsis and leads to the extensive diversity in transcript patterns due to alternative splicing. Rearrangements at the MAF2 locus are associated with an early flowering phenotype in BC(5) lines. The lack of suppression of flowering time in a MAF2-insertion line expressing the MAF2-specific artificial miRNA suggests that these MAF2 variants are behaving as loss-of-function alleles. The variation in gene architecture is also associated with segregation distortion, which may have facilitated the spread and the establishment of the corresponding alleles throughout the Eurasian range of the A. thaliana population.

Natural diversity in flowering responses of Arabidopsis thaliana caused by variation in a tandem gene array.

&#x53F6;&#x87A8;&#x87A8;&#x662F;&#x5927;&#x90FD;&#x4F1A;&#x7684;&#x519C;&#x4E1A;&#x5BB3;&#x866B;&#x4E0E;&#x5E7F;&#x6CDB;&#x7684;&#x5BC4;&#x4E3B;&#x690D;&#x7269;&#x8303;&#x56F4;&#x548C;&#x6781;&#x7AEF;&#x6297;&#x836F;&#x6027;&#x7684;&#x8BB0;&#x5F55;&#x3002;&#x5728;&#x8FD9;&#x91CC;&#x6211;&#x4EEC;&#x63D0;&#x51FA;&#x7684;&#x5B8C;&#x5168;&#x987A;&#x5E8F;&#x548C;&#x9644;&#x52A0;&#x8BF4;&#x660E;&#x87A8;&#x57FA;&#x56E0;&#x7EC4;&#x4E2D;&#xFF0C;&#x4EE3;&#x8868;&#x7B2C;&#x4E00;&#x6B21;&#x5B8C;&#x6574;&#x7684; chelicerate &#x57FA;&#x56E0;&#x7EC4;&#x3002;90 Megabases T.&#x4E8C;&#x6591;&#x53F6;&#x87A8;&#x6709;&#x5E8F;&#x6700;&#x5C0F;&#x8282;&#x80A2;&#x52A8;&#x7269;&#x57FA;&#x56E0;&#x7EC4;&#x3002;&#x76F8;&#x6BD4;&#x5176;&#x4ED6;&#x8282;&#x80A2;&#x52A8;&#x7269;&#xFF0C;&#x87A8;&#x57FA;&#x56E0;&#x7EC4;&#x663E;&#x793A;&#x4E2D;&#x6FC0;&#x7D20;&#x73AF;&#x5883;&#x548C;&#x7EC4;&#x7EC7; Hox &#x7684;&#x552F;&#x4E00;&#x53D8;&#x5316;&#x590D;&#x6742;&#xFF0C;&#x5E76;&#x8FD8;&#x63ED;&#x793A;&#x4E86;&#x6E10;&#x8FDB;&#x521B;&#x65B0;&#x7684;&#x4E1D;&#x7EF8;&#x751F;&#x4EA7;&#x3002;&#x6211;&#x4EEC;&#x53D1;&#x73B0; polyphagy &#x548C;&#x89E3;&#x6BD2;&#x7684;&#x5F3A;&#x7B7E;&#x540D;&#x4E0E;&#x9972;&#x5582;&#x4E0D;&#x540C;&#x7684;&#x4E3B;&#x673A;&#x76F8;&#x5173;&#x8054;&#x7684;&#x57FA;&#x56E0;&#x5BB6;&#x65CF;&#x4E2D;&#x83B7;&#x5F97;&#x7684;&#x6A2A;&#x5411;&#x57FA;&#x56E0;&#x8F6C;&#x79FB;&#x7684;&#x65B0;&#x7684;&#x57FA;&#x56E0;&#x5BB6;&#x65CF;&#x4E2D;&#x3002;&#x9972;&#x5582;&#x4E0D;&#x540C;&#x690D;&#x7269;&#x7684;&#x87A8;&#x6DF1;&#x8F6C;&#x5F55;&#x7EC4;&#x5206;&#x6790;&#x8868;&#x660E;&#x6B64;&#x866B;&#x5BB3;&#x5982;&#x4F55;&#x54CD;&#x5E94;&#x4E0D;&#x65AD;&#x53D8;&#x5316;&#x7684;&#x4E3B;&#x673A;&#x73AF;&#x5883;&#x3002;T.&#x4E8C;&#x6591;&#x53F6;&#x87A8;&#x57FA;&#x56E0;&#x7EC4;&#x56E0;&#x6B64;&#x63D0;&#x4F9B;&#x4E86;&#x65B0;&#x7684;&#x89C1;&#x89E3;&#x8282;&#x80A2;&#x52A8;&#x7269;&#x8FDB;&#x5316;&#x548C;&#x690D;&#x7269;&#x866B;&#x5BB3;&#x4EA4;&#x4E92;&#xFF0C;&#x5E76;&#x63D0;&#x4F9B;&#x72EC;&#x7279;&#x7684;&#x673A;&#x4F1A;&#xFF0C;&#x4E3A;&#x53D1;&#x5C55;&#x4E2D;&#x56FD;&#x5BB6;&#x7684;&#x65B0;&#x578B;&#x690D;&#x7269;&#x4FDD;&#x62A4;&#x6218;&#x7565;&#x3002;

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The spider mite Tetranychus urticae is a cosmopolitan agricultural pest with an extensive host plant range and an extreme record of pesticide resistance. Here we present the completely sequenced and annotated spider mite genome, representing the first complete chelicerate genome. At 90 megabases T. urticae has the smallest sequenced arthropod genome. Compared with other arthropods, the spider mite genome shows unique changes in the hormonal environment and organization of the Hox complex, and also reveals evolutionary innovation of silk production. We find strong signatures of polyphagy and detoxification in gene families associated with feeding on different hosts and in new gene families acquired by lateral gene transfer. Deep transcriptome analysis of mites feeding on different plants shows how this pest responds to a changing host environment. The T. urticae genome thus offers new insights into arthropod evolution and plant-herbivore interactions, and provides unique opportunities for developing novel plant protection strategies.

The genome of Tetranychus urticae reveals herbivorous pest adaptations.

L&#x26;#39;acarien Tetranychus urticae est un ravageur cosmopolite agricole avec une gamme &#xE9;tendue de la plante h&#xF4;te et un record extr&#xEA;me de la r&#xE9;sistance aux pesticides. Ici, nous pr&#xE9;sentons le g&#xE9;nome enti&#xE8;rement s&#xE9;quenc&#xE9; araign&#xE9;e et annot&#xE9; acariens, ce qui repr&#xE9;sente le premier g&#xE9;nome complet chelicerate. &#xC0; 90 m&#xE9;gabases T. urticae a le plus petit g&#xE9;nome s&#xE9;quenc&#xE9; arthropodes. En comparaison avec d&#x26;#39;autres arthropodes, le g&#xE9;nome araign&#xE9;e montre les modifications uniques dans l&#x26;#39;environnement hormonal et l&#x26;#39;organisation du complexe Hox, et r&#xE9;v&#xE8;le &#xE9;galement l&#x26;#39;innovation &#xE9;volutive de la production de soie. Nous trouver des signatures fortes de polyphagie et de d&#xE9;sintoxication dans des familles de g&#xE8;nes associ&#xE9;s &#xE0; l&#x26;#39;alimentation sur des h&#xF4;tes diff&#xE9;rents et dans des familles de g&#xE8;nes nouveaux acquis par transfert lat&#xE9;ral de g&#xE8;nes. Profonde analyse du transcriptome des acariens se nourrissent de plantes diff&#xE9;rentes montre comment ce ravageur r&#xE9;pond &#xE0; un milieu d&#x26;#39;accueil de changer. Le g&#xE9;nome T. urticae offre ainsi de nouvelles perspectives sur l&#x26;#39;&#xE9;volution des arthropodes et des interactions plantes-herbivores, et offre des possibilit&#xE9;s uniques pour d&#xE9;velopper de nouvelles strat&#xE9;gies phytosanitaires.

Le g&#xE9;nome de Tetranychus urticae r&#xE9;v&#xE8;le Adaptations Pest herbivores

Die Spinnmilben Gemeine Spinnmilbe ist eine kosmopolitische landwirtschaftlichen Sch&auml;dlingsbek&auml;mpfung mit einer umfangreichen Anlage Wirtsbereich und eine extreme Aufzeichnung der Pestizid-Resistenz. Hier pr&auml;sentieren wir das Genom vollst&auml;ndig sequenziert und kommentierten Spinnmilben, das erste vollst&auml;ndige chelicerate Genom darstellt. 90 Megabases hat T. Urticae kleinster sequenzierte gliederf&uuml;&szlig;ler Genom. Verglichen mit anderen Arthropoden, das Spinnmilben-Genom zeigt einzigartige Ver&auml;nderungen in der hormonellen Umgebung und Organisation von der Hox komplexe und offenbart auch evolution&auml;re Innovation der Seidenherstellung. Wir finden starke Signaturen von Polyphagy und Entgiftung in gen-Familien, die F&uuml;tterung auf unterschiedlichen Hosts zugeordnet und in neuen Gen-Familien von lateralen Gentransfer erworben. Tiefe Transkriptom-Analyse der Milben fressen verschiedene Pflanzen zeigt wie diese Pest auf einem sich wandelnden Umfeld Host reagiert. T. Urticae Genom somit bietet neue Einblicke in gliederf&uuml;&szlig;ler Evolution und Interaktionen von Pflanzen-Pflanzenfresser und bietet einzigartige M&ouml;glichkeiten f&uuml;r die Entwicklung neuartiger Pflanze Schutzstrategien.

Das Genom der Gemeine Spinnmilbe enth&uuml;llt pflanzenfressenden Pest Anpassungen.

Il ragno acaro Tetranychus urticae &egrave; un parassita cosmopolito agricolo con un&#39;ampia gamma di pianta e un record di estremo di resistenza ai pesticidi. Qui vi presentiamo il genoma completamente sequenziato ed annotata ragnetto, che rappresenta il primo genoma di chelicerati completo. 90 Megabasi T. urticae ha il pi&ugrave; piccolo genoma degli artropodi sequenziato. Confrontato con altri artropodi, il genoma del ragnetto Mostra uniche modifiche nell&#39;ambiente ormonale e organizzazione della Hox complessi e rivela anche l&#39;innovazione evolutiva della produzione di seta. Troviamo forte firme di polyphagy e di disintossicazione in famiglie gene associate con alimentazione su diversi host e in nuove famiglie di gene acquisite da trasferimento genico laterale. Transcriptome profonda analisi di acari sulle piante differenti di alimentazione mostra come questo parassita risponde a un mutevole ambiente host. Cos&igrave; il genoma di T. urticae offre nuove intuizioni evoluzione degli artropodi e interazioni pianta-erbivoro e offre opportunit&agrave; uniche per impianto di romanzo in via di sviluppo le strategie di protezione.

Il genoma di Tetranychus urticae rivela gli adattamenti dei parassiti erbivori.

&#x30CF;&#x30C0;&#x30CB;&#x30CA;&#x30DF;&#x30CF;&#x30C0;&#x30CB;&#x306F;&#x3001;&#x5E83;&#x7BC4;&#x306A;&#x5BBF;&#x4E3B;&#x690D;&#x7269;&#x306E;&#x7BC4;&#x56F2;&#x53CA;&#x3073;&#x8FB2;&#x85AC;&#x62B5;&#x6297;&#x6027;&#x306E;&#x6975;&#x7AEF;&#x306A;&#x30EC;&#x30B3;&#x30FC;&#x30C9;&#x3092;&#x6301;&#x3064;&#x56FD;&#x969B;&#x7684;&#x306A;&#x8FB2;&#x696D;&#x5BB3;&#x866B;&#x3067;&#x3042;&#x308B;&#x3002;&#x3053;&#x3053;&#x3067;&#x306F;&#x3001;&#x6700;&#x521D;&#x306E;&#x5B8C;&#x5168;&#x306A;&#x92CF;&#x89D2;&#x3092;&#x6301;&#x3064;&#x30B2;&#x30CE;&#x30E0;&#x3092;&#x8868;&#x3059;&#x3001;&#x5B8C;&#x5168;&#x306B;&#x914D;&#x5217;&#x6C7A;&#x5B9A;&#x3057;&#x3001;&#x6CE8;&#x91C8;&#x4ED8;&#x304D;&#x306E;&#x30CF;&#x30C0;&#x30CB;&#x306E;&#x30B2;&#x30CE;&#x30E0;&#x3092;&#x63D0;&#x793A;&#x3057;&#x307E;&#x3059;&#x3002; 90&#x30E1;&#x30AC;&#x3067;&#x306E;&#x30CA;&#x30DF;&#x30CF;&#x30C0;&#x30CB;&#x306F;&#x3001;&#x6700;&#x5C0F;&#x30B7;&#x30FC;&#x30B1;&#x30F3;&#x30B9;&#x7BC0;&#x8DB3;&#x52D5;&#x7269;&#x306E;&#x30B2;&#x30CE;&#x30E0;&#x3092;&#x6301;&#x3063;&#x3066;&#x3044;&#x307E;&#x3059;&#x3002;&#x4ED6;&#x306E;&#x7BC0;&#x8DB3;&#x52D5;&#x7269;&#x3068;&#x6BD4;&#x8F03;&#x3057;&#x3001;&#x30CF;&#x30C0;&#x30CB;&#x306E;&#x30B2;&#x30CE;&#x30E0;&#x306F;&#x3001;Hox&#x907A;&#x4F1D;&#x5B50;&#x8907;&#x5408;&#x4F53;&#x306E;&#x30DB;&#x30EB;&#x30E2;&#x30F3;&#x74B0;&#x5883;&#x3068;&#x7D44;&#x7E54;&#x5185;&#x3067;&#x4E00;&#x610F;&#x306E;&#x5909;&#x5316;&#x3092;&#x793A;&#x3057;&#x3001;&#x307E;&#x305F;&#x3001;&#x7D79;&#x751F;&#x7523;&#x306E;&#x9032;&#x5316;&#x306E;&#x6280;&#x8853;&#x9769;&#x65B0;&#x3092;&#x660E;&#x3089;&#x304B;&#x306B;&#x3059;&#x308B;&#x3002;&#x6211;&#x3005;&#x306F;&#x3001;&#x7570;&#x306A;&#x308B;&#x30DB;&#x30B9;&#x30C8;&#x4E0A;&#x3067;&#x6442;&#x98DF;&#x306B;&#x95A2;&#x9023;&#x3059;&#x308B;&#x907A;&#x4F1D;&#x5B50;&#x30D5;&#x30A1;&#x30DF;&#x30EA;&#x30FC;&#x3084;&#x907A;&#x4F1D;&#x5B50;&#x6C34;&#x5E73;&#x8EE2;&#x79FB;&#x306B;&#x3088;&#x3063;&#x3066;&#x53D6;&#x5F97;&#x3055;&#x308C;&#x305F;&#x65B0;&#x305F;&#x306A;&#x907A;&#x4F1D;&#x5B50;&#x30D5;&#x30A1;&#x30DF;&#x30EA;&#x30FC;&#x306E;&#x591A;&#x98DF;&#x3068;&#x89E3;&#x6BD2;&#x306E;&#x5F37;&#x529B;&#x306A;&#x7F72;&#x540D;&#x3092;&#x898B;&#x3064;&#x3051;&#x308B;&#x3002;&#x7570;&#x306A;&#x3063;&#x305F;&#x690D;&#x7269;&#x3092;&#x98DF;&#x3079;&#x3066;&#x30C0;&#x30CB;&#x306E;&#x6DF1;&#x3044;&#x30C8;&#x30E9;&#x30F3;&#x30B9;&#x30AF;&#x30EA;&#x30D7;&#x30C8;&#x30FC;&#x30E0;&#x89E3;&#x6790;&#x306F;&#x3001;&#x3053;&#x306E;&#x5BB3;&#x866B;&#x304C;&#x5909;&#x5316;&#x3057;&#x3001;&#x30DB;&#x30B9;&#x30C8;&#x74B0;&#x5883;&#x306B;&#x5FDC;&#x7B54;&#x3059;&#x308B;&#x65B9;&#x6CD5;&#x3092;&#x793A;&#x3057;&#x3066;&#x3044;&#x307E;&#x3059;&#x3002;&#x30CA;&#x30DF;&#x30CF;&#x30C0;&#x30CB;&#x306E;&#x30B2;&#x30CE;&#x30E0;&#x306F;&#x3001;&#x3053;&#x306E;&#x3088;&#x3046;&#x306B;&#x7BC0;&#x8DB3;&#x52D5;&#x7269;&#x306E;&#x9032;&#x5316;&#x3068;&#x690D;&#x7269;&#x8349;&#x98DF;&#x52D5;&#x7269;&#x306E;&#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x306B;&#x65B0;&#x305F;&#x306A;&#x6D1E;&#x5BDF;&#x3092;&#x63D0;&#x4F9B;&#x3057;&#x3001;&#x65B0;&#x305F;&#x306A;&#x690D;&#x7269;&#x4FDD;&#x8B77;&#x6226;&#x7565;&#x3092;&#x958B;&#x767A;&#x3059;&#x308B;&#x305F;&#x3081;&#x306E;&#x30E6;&#x30CB;&#x30FC;&#x30AF;&#x306A;&#x6A5F;&#x4F1A;&#x3092;&#x63D0;&#x4F9B;&#x3057;&#x3066;&#x3044;&#x307E;&#x3059;&#x3002;

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&#xAC70;&#xBBF8; &#xC9C4;&#xB4DC;&#xAE30; Tetranychus urticae &#xAD11;&#xBC94;&#xC704; &#xD55C; &#xD638;&#xC2A4;&#xD2B8; &#xACF5;&#xC7A5; &#xBC94;&#xC704;&#xC640; &#xB18D;&#xC57D; &#xC800;&#xD56D;&#xC758; &#xADF9;&#xB2E8;&#xC801;&#xC778; &#xAE30;&#xB85D; &#xAD6D;&#xC81C; &#xB18D;&#xC5C5; &#xD574;&#xCDA9; &#xC774;&#xB2E4;. &#xC5EC;&#xAE30;&#xC5D0; &#xC6B0;&#xB9AC;&#xAC00; &#xD604;&#xC7AC; &#xC644;&#xC804;&#xD788; &#xC2DC;&#xD000;&#xC2A4; &#xBC0F; &#xC8FC;&#xC11D; &#xB2EC;&#xB9B0; &#xAC70;&#xBBF8; &#xB9C8;&#xC774;&#xD2B8; &#xAC8C;&#xB188; &#xB098;&#xD0C0;&#xB0B4;&#xB294; &#xCCAB; &#xBC88;&#xC9F8; &#xC644;&#xC804; &#xD55C; chelicerate &#xAC8C;&#xB188;. 90 Megabases T. urticae&#xB294; &#xAC00;&#xC7A5; &#xC791;&#xC740; &#xC2DC;&#xD000;&#xC2A4; arthropod &#xAC8C;&#xB188;. &#xB2E4;&#xB978; arthropods&#xC5D0; &#xBE44;&#xD574;, &#xAC70;&#xBBF8; &#xC9C4;&#xB4DC;&#xAE30; &#xAC8C;&#xB188; &#xBCF5;&#xC7A1; &#xD558; &#xACE0;, &#xD638;&#xB974;&#xBAAC; &#xD658;&#xACBD;&#xACFC; Hox&#xC758; &#xC870;&#xC9C1;&#xC5D0; &#xC788;&#xB294; &#xACE0;&#xC720; &#xBCC0;&#xACBD; &#xD45C;&#xC2DC; &#xD558; &#xACE0; &#xB610;&#xD55C; &#xC2E4;&#xD06C; &#xC0DD;&#xC0B0;&#xC758; &#xC9C4;&#xD654; &#xD601;&#xC2E0;&#xC744; &#xBCF4;&#xC5EC;. &#xC6B0;&#xB9AC;&#xB294; &#xB2E4;&#xB978; &#xD638;&#xC2A4;&#xD2B8;&#xC5D0;&#xC11C; &#xC218; &#xC720;&#xC640; &#xAD00;&#xB828; &#xB41C; &#xC720;&#xC804;&#xC790; &#xAC00;&#xC871; &#xADF8;&#xB9AC;&#xACE0; &#xC0C8;&#xB85C;&#xC6B4; &#xC720;&#xC804;&#xC790; &#xAC00;&#xC871; &#xC606; &#xC720;&#xC804;&#xC790; &#xC774;&#xB3D9;&#xC5D0; &#xC758;&#xD574; &#xC778;&#xC218; polyphagy&#xC640; &#xD574;&#xB3C5;&#xC758; &#xAC15;&#xB825;&#xD55C; &#xC11C;&#xBA85;&#xC758; &#xCC3E;&#xC744;. &#xBA39;&#xC774; &#xB2E4;&#xB978; &#xC2DD;&#xBB3C;&#xC5D0; &#xC9C4;&#xB4DC;&#xAE30;&#xC758; &#xAE4A;&#xC740; transcriptome &#xBD84;&#xC11D;&#xC774;&#xC774; &#xD574;&#xCDA9; &#xBCC0;&#xD654; &#xD638;&#xC2A4;&#xD2B8; &#xD658;&#xACBD;&#xC5D0; &#xC751;&#xB2F5; &#xD558;&#xB294; &#xBC29;&#xBC95;&#xC744; &#xBCF4;&#xC5EC; &#xC90D;&#xB2C8;&#xB2E4;. &#xB530;&#xB77C;&#xC11C; T. urticae &#xAC8C;&#xB188; arthropod &#xC9C4;&#xD654;&#xC640; &#xC2DD;&#xBB3C; &#xCD08; &#xC2DD; &#xB3D9;&#xBB3C; &#xC0C1;&#xD638; &#xC791;&#xC6A9;&#xC5D0; &#xB300; &#xD55C; &#xC0C8;&#xB85C;&#xC6B4; &#xD1B5;&#xCC30;&#xB825;&#xC744; &#xC81C;&#xACF5; &#xD558; &#xACE0; &#xBCF4;&#xD638; &#xC804;&#xB7B5; &#xAC1C;&#xBC1C; &#xC18C;&#xC124; &#xACF5;&#xC7A5;&#xC5D0; &#xB300; &#xD55C; &#xB3C5;&#xD2B9;&#xD55C; &#xAE30;&#xD68C;&#xB97C; &#xC81C;&#xACF5; &#xD569;&#xB2C8;&#xB2E4;.

Tetranychus urticae&#xC758; &#xAC8C;&#xB188; &#xACC4; &#xD574;&#xCDA9;&#xC744; &#xAC01; &#xC0C9; &#xD55C;&#xC744; &#xBCF4;&#xC5EC;&#xC900;&#xB2E4;.

La ara&#xF1;a roja Tetranychus urticae es una plaga cosmopolita agr&#xED;cola con una gama extensa de la planta hospedante y un registro extremo de la resistencia a los pesticidas. Aqu&#xED; se presenta el genoma de ara&#xF1;a roja por completo secuenciado y anotado, lo que representa el primer genoma completo chelicerate. A los 90 megabases T. urticae tiene el m&#xE1;s peque&#xF1;o secuenciado genoma artr&#xF3;podo. En comparaci&#xF3;n con otros artr&#xF3;podos, el genoma de la ara&#xF1;a roja muestra los cambios singulares en el entorno hormonal y la organizaci&#xF3;n del complejo Hox, y tambi&#xE9;n revela la innovaci&#xF3;n evolutiva de la producci&#xF3;n de seda. Encontramos firmas fuertes de polyphagy y la desintoxicaci&#xF3;n de las familias de genes asociados con la alimentaci&#xF3;n en diferentes equipos y en las familias de genes nuevos adquiridos por transferencia lateral de genes. An&#xE1;lisis profundo del transcriptoma de los &#xE1;caros se alimentan de plantas diferentes muestra que esta plaga responde a un entorno de acogida cambiando. El genoma de T. urticae por tanto, ofrece nuevas perspectivas sobre la evoluci&#xF3;n de artr&#xF3;podos y de las interacciones planta-herb&#xED;voro, y proporciona oportunidades &#xFA;nicas para el desarrollo de nuevas estrategias de protecci&#xF3;n de plantas.

El genoma de T. urticae revela adaptaciones herb&#xED;voros plagas

Cysteine peptidases in the two-spotted spider mite Tetranychus urticae are involved in essential physiological processes, including proteolytic digestion. Cystatins and thyropins are inhibitors of cysteine peptidases that modulate their activity, although their function in this species has yet to be investigated. Comparative genomic analyses are powerful tools to obtain advanced knowledge into the presence and evolution of both, peptidases and their inhibitors, and could aid to elucidate issues concerning the function of these proteins.

Cysteine peptidases and their inhibitors in Tetranychus urticae: a comparative genomic approach.

The two-spotted spider mite Tetranychus urticae is a damaging pest worldwide with a wide range of host plants and an extreme record of pesticide resistance. Recently, the complete T. urticae genome has been published and showed a proliferation of gene families associated with digestion and detoxification of plant secondary compounds which supports its polyphagous behaviour. To overcome spider mite adaptability a gene pyramiding approach has been developed by co-expressing two barley proteases inhibitors, the cystatin Icy6 and the trypsin inhibitor Itr1 genes in Arabidopsis plants by Agrobacterium-mediated transformation. The presence and expression of both transgenes was studied by conventional and quantitative real time RT-PCR assays and by indirect ELISA assays. The inhibitory activity of cystatin and trypsin inhibitor was in vitro analysed using specific substrates. Single and double transformants were used to assess the effects of spider mite infestation. Double transformed lines showed the lowest damaged leaf area in comparison to single transformants and non-transformed controls and different accumulation of H(2)O(2) as defence response in the leaf feeding site, detected by diaminobenzidine staining. Additionally, an impact on endogenous mite cathepsin B- and L-like activities was observed after feeding on Arabidopsis lines, which correlates with a significant increase in the mortality of mites fed on transformed plants. These effects were analysed in view of the expression levels of the target mite protease genes, C1A cysteine peptidase and S1 serine peptidase, identified in the four developmental mite stages (embryo, larvae, nymphs and adults) performed using the RNA-seq information available at the BOGAS T. urticae database. The potential of pyramiding different classes of plant protease inhibitors to prevent plant damage caused by mites as a new tool to prevent pest resistance and to improve pest control is discussed.

Gene pyramiding of peptidase inhibitors enhances plant resistance to the spider mite Tetranychus urticae.

The MADS-AFFECTING FLOWERING 2 (MAF2) gene of Arabidopsis thaliana has been characterized as a repressor of flowering. The molecular basis of MAF2 gene function and role of alternative MAF2 transcripts in flowering time modulation is not understood. MAF2 splice variant expression was quantified in cold-acclimated plants by quantitative RT-PCR. Cold influenced the abundance of splice variants and prompted a functional study of splice forms. Individual variants were overexpressed in the Col background and were assayed for their ability to delay flowering. Overexpression of MAF2 variants 2 and 4 had limited effect on flowering time. Overexpression of MAF2 splice variant 1 resulted in early flowering and affected the expression of the endogenous MAF2 gene and its paralogues, confounding functional assessment. In the Ll-2 Arabidopsis accession, a MAF2, MAF3, MAF4 and FLC null line, MAF2 var1 was consistent in its effect on reproductive delay under ambient and reduced temperatures, indicating that it acts as a repressor of flowering.

Functional analysis of splice variant expression of MADS AFFECTING FLOWERING 2 of Arabidopsis thaliana.

In indeterminate inflorescences, floral meristems develop on the flanks of the shoot apical meristem, at positions determined by auxin maxima. The floral identity of these meristems is conferred by a handful of genes called floral meristem identity genes, among which the LEAFY (LFY) transcription factor plays a prominent role. However, the molecular mechanism controlling the early emergence of floral meristems remains unknown. A body of evidence indicates that LFY may contribute to this developmental shift, but a direct effect of LFY on meristem emergence has not been demonstrated. We have generated a LFY allele with reduced floral function and revealed its ability to stimulate axillary meristem growth. This role is barely detectable in the lfy single mutant but becomes obvious in several double mutant backgrounds and plants ectopically expressing LFY. We show that this role requires the ability of LFY to bind DNA, and is mediated by direct induction of REGULATOR OF AXILLARY MERISTEMS1 (RAX1) by LFY. We propose that this function unifies the diverse roles described for LFY in multiple angiosperm species, ranging from monocot inflorescence identity to legume leaf development, and that it probably pre-dates the origin of angiosperms.

A variant of LEAFY reveals its capacity to stimulate meristem development by inducing RAX1.

Plant-herbivore relationships are complex interactions encompassing elaborate networks of molecules, signals and strategies used to overcome defences developed by each other. Herbivores use multiple feeding strategies to obtain nutrients from host plants. In turn, plants respond by triggering defence mechanisms to inhibit, block or modify the metabolism of the pest. As part of these defences, herbivore-challenged plants emit volatiles to attract natural enemies and warn neighbouring plants of the imminent threat. In response, herbivores develop a variety of strategies to suppress plant-induced protection. Our understanding of the plant-herbivore interphase is limited, although recent molecular approaches have revealed the participation of a battery of genes, proteins and volatile metabolites in attack-defence processes. This review describes the intricate and dynamic defence systems governing plant-herbivore interactions by examining the diverse strategies plants employ to deny phytophagous arthropods the ability to breach newly developed mechanisms of plant resistance. A cornerstone of this understanding is the use of transgenic tools to unravel the complex networks that control these interactions.

Understanding plant defence responses against herbivore attacks: an essential first step towards the development of sustainable resistance against pests.

Most molecular-genetic studies of plant defense responses to arthropod herbivores have focused on insects. However, plant-feeding mites are also pests of diverse plants, and mites induce different patterns of damage to plant tissues than do well-studied insects (e.g. lepidopteran larvae or aphids). The two-spotted spider mite (Tetranychus urticae) is among the most significant mite pests in agriculture, feeding on a staggering number of plant hosts. To understand the interactions between spider mite and a plant at the molecular level, we examined reciprocal genome-wide responses of mites and its host Arabidopsis (Arabidopsis thaliana). Despite differences in feeding guilds, we found that transcriptional responses of Arabidopsis to mite herbivory resembled those observed for lepidopteran herbivores. Mutant analysis of induced plant defense pathways showed functionally that only a subset of induced programs, including jasmonic acid signaling and biosynthesis of indole glucosinolates, are central to Arabidopsis's defense to mite herbivory. On the herbivore side, indole glucosinolates dramatically increased mite mortality and development times. We identified an indole glucosinolate dose-dependent increase in the number of differentially expressed mite genes belonging to pathways associated with detoxification of xenobiotics. This demonstrates that spider mite is sensitive to Arabidopsis defenses that have also been associated with the deterrence of insect herbivores that are very distantly related to chelicerates. Our findings provide molecular insights into the nature of, and response to, herbivory for a representative of a major class of arthropod herbivores.

Article	Year
Axillary meristem development in the branchless Zu-0 ecotype of Arabidopsis thaliana. Planta\| PubMed ID: 12244434	2002
The synergistic activation of FLOWERING LOCUS C by FRIGIDA and a new flowering gene AERIAL ROSETTE 1 underlies a novel morphology in Arabidopsis. Genetics\| PubMed ID: 12702689	2003
A map of KNAT gene expression in the Arabidopsis root. Plant molecular biology\| PubMed ID: 16463096	2006
Vacuolar cysteine proteases of wheat (Triticum aestivum L.) are common to leaf senescence induced by different factors. Journal of experimental botany\| PubMed ID: 17218544	2007
Mity model: Tetranychus urticae, a candidate for chelicerate model organism. BioEssays : news and reviews in molecular, cellular and developmental biology\| PubMed ID: 17450600	2007
HUA2 caused natural variation in shoot morphology of A. thaliana. Current biology : CB\| PubMed ID: 17764945	2007
Control of lateral organ development and flowering time by the Arabidopsis thaliana MADS-box Gene AGAMOUS-LIKE6. The Plant journal : for cell and molecular biology\| PubMed ID: 20230491	2010
Natural diversity in flowering responses of Arabidopsis thaliana caused by variation in a tandem gene array. Genetics\| PubMed ID: 20551443	2010
The genome of Tetranychus urticae reveals herbivorous pest adaptations. Nature\| PubMed ID: 22113690	2011
Cysteine peptidases and their inhibitors in Tetranychus urticae: a comparative genomic approach. BMC genomics\| PubMed ID: 22784002	2012
Gene pyramiding of peptidase inhibitors enhances plant resistance to the spider mite Tetranychus urticae. PloS one\| PubMed ID: 22900081	2012
Functional analysis of splice variant expression of MADS AFFECTING FLOWERING 2 of Arabidopsis thaliana. Plant molecular biology\| PubMed ID: 23111501	2013
A variant of LEAFY reveals its capacity to stimulate meristem development by inducing RAX1. The Plant journal : for cell and molecular biology\| PubMed ID: 23445516	2013
Understanding plant defence responses against herbivore attacks: an essential first step towards the development of sustainable resistance against pests. Transgenic research\| PubMed ID: 23793555	2013
Reciprocal responses in the interaction between Arabidopsis and the cell-content-feeding chelicerate herbivore spider mite. Plant physiology\| PubMed ID: 24285850	2014

Vojislava Grbic

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