{"id":714,"date":"2022-02-22T23:10:18","date_gmt":"2022-02-22T22:10:18","guid":{"rendered":"https:\/\/pedagogie.ac-lille.fr\/svt\/?p=714"},"modified":"2022-02-22T23:19:34","modified_gmt":"2022-02-22T22:19:34","slug":"la-selection-de-la-tomate-sans-gout","status":"publish","type":"post","link":"https:\/\/pedagogie.ac-lille.fr\/svt\/la-selection-de-la-tomate-sans-gout\/","title":{"rendered":"La s\u00e9lection de la tomate sans go\u00fbt"},"content":{"rendered":"<p>Depuis les ann\u00e9es 1950, les s\u00e9lections effectu\u00e9es sur la Tomate ont permis l\u2019obtention de fruits d\u2019apparence parfaite, bien uniformes et sans collet vert, comme pouvaient le pr\u00e9senter les vari\u00e9t\u00e9s anciennes.<\/p>\n<p>La s\u00e9lection d\u2019un all\u00e8le r\u00e9cessif \u00ab\u00a0u\u00a0\u00bb pour \u00ab\u00a0uniform ripening\u00a0\u00bb du g\u00e8ne SIGLK2 a permis la production de belles tomates d\u2019un rouge uni, mais ayant perdu 20% de leur taux de glucides lors du m\u00fbrissement et donc sans go\u00fbt. Le fichier EDI ci-dessous permet de comparer les s\u00e9quences partielles des all\u00e8les normal\/mut\u00e9 : On y constate l&rsquo;apparition d\u2019un codon stop au niveau de l\u2019ARNm de l\u2019all\u00e8le mut\u00e9.<\/p>\n<p style=\"text-align: center\"><a class=\"internal-link\" title=\"\" href=\"http:\/\/svt.discipline.ac-lille.fr\/docs\/AlllesdugneGLK2Tomate.edi.zip\" target=\"_self\" rel=\"noopener\">\u00a0All\u00e8les U et u de SIGKL2<\/a><\/p>\n<p>La raison est \u00e0 chercher dans ce collet vert si particulier des vari\u00e9t\u00e9s anciennes : l\u2019all\u00e8le U dominant du g\u00e8ne SIGLK2 permet la production de chloroplastes mais aussi la formation de nombreux thylako\u00efdes dans ces organites au niveau du collet vert, ce qui permet la production d\u2019un suppl\u00e9ment de glucides par photosynth\u00e8se, avant que les chloroplastes ne se transforment en chromoplastes. La photo ci-dessous montre les cons\u00e9quences de cette mutation sur les chloroplastes.<\/p>\n<figure id=\"attachment_721\" aria-describedby=\"caption-attachment-721\" style=\"width: 570px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate2.png\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-721 size-full\" src=\"http:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate2.png\" alt=\"\" width=\"570\" height=\"354\" srcset=\"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate2.png 570w, https:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate2-300x186.png 300w\" sizes=\"auto, (max-width: 570px) 100vw, 570px\" \/><\/a><figcaption id=\"caption-attachment-721\" class=\"wp-caption-text\">\u00e0 droite : Arabidopsis t\u00e9moin, \u00e0 gauche Arabidopsis au g\u00e8ne GLK mut\u00e9.<\/figcaption><\/figure>\n<p>La tomate dont l\u2019all\u00e8le U est dominant (U\/U) est plus verte, plus fonc\u00e9e et sa couleur est moins r\u00e9guli\u00e8re que celle au vert livide et uniforme porteuse du caract\u00e8re r\u00e9cessif (u\/u).<\/p>\n<figure id=\"attachment_720\" aria-describedby=\"caption-attachment-720\" style=\"width: 366px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate3.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-720\" src=\"http:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate3.png\" alt=\"\" width=\"366\" height=\"410\" srcset=\"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate3.png 366w, https:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate3-268x300.png 268w\" sizes=\"auto, (max-width: 366px) 100vw, 366px\" \/><\/a><figcaption id=\"caption-attachment-720\" class=\"wp-caption-text\">\u00a9 C. Nguyen and J. Giovannoni<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><a href=\"http:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate4.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-719\" src=\"http:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate4.png\" alt=\"\" width=\"654\" height=\"506\" srcset=\"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate4.png 654w, https:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate4-300x232.png 300w\" sizes=\"auto, (max-width: 654px) 100vw, 654px\" \/><\/a><b>Le r\u00e9fractom\u00e8tre<\/b> peut \u00eatre utilis\u00e9 pour estimer la concentration d\u2019une substance dans une solution. Plus la concentration d\u2019une substance est \u00e9lev\u00e9e, plus la r\u00e9fraction de la lumi\u00e8re est importante. Ici, le r\u00e9fractom\u00e8tre ne mesure pas uniquement les teneurs en glucose et fructose de la tomate obtenus \u00e0 partir de l\u2019amidon lors du m\u00fbrissement, mais\u00a0 la comparaison des pourcentages (Brix) obtenus pour diff\u00e9rents fruits permet d\u2019estimer l\u2019accumulation relative de ces glucides repr\u00e9sentant l\u2019essentiel des mol\u00e9cules form\u00e9es. Les tomates utilis\u00e9es doivent toutes \u00eatre au m\u00eame stade de m\u00fbrissement.<\/p>\n<p style=\"text-align: center\"><a href=\"http:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate5.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-718\" src=\"http:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate5.png\" alt=\"\" width=\"746\" height=\"501\" srcset=\"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate5.png 746w, https:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate5-300x201.png 300w\" sizes=\"auto, (max-width: 746px) 100vw, 746px\" \/><\/a><\/p>\n<p><b>Coupes fines (\u00e0 la lame de rasoir) de tomates et observations microscopiques :<\/b><\/p>\n<figure id=\"attachment_717\" aria-describedby=\"caption-attachment-717\" style=\"width: 636px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate6.png\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-717 size-full\" src=\"http:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate6.png\" alt=\"\" width=\"636\" height=\"470\" srcset=\"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate6.png 636w, https:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate6-300x222.png 300w\" sizes=\"auto, (max-width: 636px) 100vw, 636px\" \/><\/a><figcaption id=\"caption-attachment-717\" class=\"wp-caption-text\">Coupe dans une vari\u00e9t\u00e9 ancienne \u00ab\u00a0Green zebra\u00a0\u00bb : Chloroplastes dans les cellules \u00e0 la p\u00e9riph\u00e9rie de la tomate<\/figcaption><\/figure>\n<figure id=\"attachment_716\" aria-describedby=\"caption-attachment-716\" style=\"width: 570px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate7.png\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-716 size-full\" src=\"http:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate7.png\" alt=\"\" width=\"570\" height=\"418\" srcset=\"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate7.png 570w, https:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate7-300x220.png 300w\" sizes=\"auto, (max-width: 570px) 100vw, 570px\" \/><\/a><figcaption id=\"caption-attachment-716\" class=\"wp-caption-text\">Coupe dans une tomate \u00ab\u00a0noire de Crim\u00e9e\u00a0\u00bb : Chloroplastes et beaucoup de chromoplastes issus de nombreux chloroplastes dans le collet vert de la Noire de Crim\u00e9e<\/figcaption><\/figure>\n<figure id=\"attachment_715\" aria-describedby=\"caption-attachment-715\" style=\"width: 564px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate8.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-715\" src=\"http:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate8.png\" alt=\"\" width=\"564\" height=\"413\" srcset=\"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate8.png 564w, https:\/\/pedagogie.ac-lille.fr\/svt\/wp-content\/uploads\/sites\/34\/2022\/02\/tomate8-300x220.png 300w\" sizes=\"auto, (max-width: 564px) 100vw, 564px\" \/><\/a><figcaption id=\"caption-attachment-715\" class=\"wp-caption-text\">Coupe dans une tomate rouge uniforme : Peu de chromoplastes (rouges car charg\u00e9s de lycop\u00e8nes et ayant perdu la chlorophylle) car peu de chloroplastes initialement dans la tomate sans go\u00fbt, d\u2019un rouge uniforme<\/figcaption><\/figure>\n<p align=\"right\"><em>Didier Pr\u00e9vost \u2013 lyc\u00e9e Guy Mollet &#8211; Arras<\/em><\/p>\n<p align=\"right\"><i>Merci pour l\u2019aide pr\u00e9cieuse de C\u00e9line Vansteenkiste et de Claude Torr\u00e9 du lyc\u00e9e Raymond Queneau de Villeneuve d\u2019Ascq<\/i><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Depuis les ann\u00e9es 1950, les s\u00e9lections effectu\u00e9es sur la Tomate ont permis l\u2019obtention de fruits d\u2019apparence parfaite, bien uniformes et sans collet vert, comme pouvaient le pr\u00e9senter les vari\u00e9t\u00e9s anciennes. [&hellip;]<\/p>\n","protected":false},"author":50,"featured_media":722,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[18],"tags":[],"class_list":{"0":"post-714","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-terminale-specialite","8":"czr-hentry"},"publishpress_future_action":{"enabled":false,"date":"2026-04-13 19:29:18","action":"change-status","newStatus":"draft","terms":[],"taxonomy":"category","extraData":[]},"publishpress_future_workflow_manual_trigger":{"enabledWorkflows":[]},"_links":{"self":[{"href":"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-json\/wp\/v2\/posts\/714","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-json\/wp\/v2\/users\/50"}],"replies":[{"embeddable":true,"href":"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-json\/wp\/v2\/comments?post=714"}],"version-history":[{"count":8,"href":"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-json\/wp\/v2\/posts\/714\/revisions"}],"predecessor-version":[{"id":730,"href":"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-json\/wp\/v2\/posts\/714\/revisions\/730"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-json\/wp\/v2\/media\/722"}],"wp:attachment":[{"href":"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-json\/wp\/v2\/media?parent=714"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-json\/wp\/v2\/categories?post=714"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pedagogie.ac-lille.fr\/svt\/wp-json\/wp\/v2\/tags?post=714"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}