Growth, yield and shelf-life of isopentenyltransferase (ipt)-gene transformed broccoli

Abstract

. 2009. Growth, yield and shelf-life of isopentenyltransferase (ipt)-gene transformed broccoli. Can. J. Plant Sci. 89: 701Á711. Loss of chlorophyll leading to floret yellowing limits the post-harvest lifespan of broccoli (Brassica oleracea L. var. italica Plenck). Cytokinins are known to delay floral yellowing of plants. A transgene construct pSG766A, which results in the expression of isopentenyltransferase (ipt), the key enzyme for cytokinin synthesis, has been developed in broccoli. Expression of the ipt transgene is triggered by the senescence-associated gene promoter (SAG-13). Three selfed T 5 lines of ipt transformed broccoli (lines 101, 102 and 103) have been obtained through selection for single copy insertion, acceptable horticultural traits and transgene ipt activity. These three transgenic inbred lines were evaluated in the field during 2004Á 2007 to determine their growth, yield and shelf-life after harvest, relative to a non-transgenic inbred line (104) and the parental variety Green King. For most of the vegetative growth parameters measured, year-to-year variability exceeded line-to-line variability. Inbreeding had little impact on the appearance or yield potential of the broccoli lines. Head yields of the transgenic inbred lines 102 and 103 were comparable to the parental variety Green King, but were significantly higher than the non-transgenic inbred line 104, as lines 102 and 103 produced more plants with heavier flower heads. Cytokinin content in the form of isopentenyladenosine was relatively higher in the transgenic lines than in the two nontransgenic controls. When flower heads were stored at 25928C, the period required to cause 50% floret yellowing was 7.5 and 8. Plant Sci. 89: 701Á711. La perte de chlorophylle responsable du jaunissement des fleurons diminue la dure´e de conservation apre`s re´colte du brocoli (Brassica oleracea L. var. italica Plenck). On sait que les cytokinines retardent le jaunissement des fleurs chez les plantes. Par ailleurs, on a cre´e´le transge`ne pSG766A, qui exprime l'isopente´nyltransfe´rase (ipt), principal enzyme responsable de la synthe`se des cytokinines chez le brocoli. L'expression de ce ge`ne est de´clenche´e par le promoteur SAG-13, associe´a`la se´nescence. Les auteurs ont obtenu trois ligne´es T 5 autofe´conde´es de brocoli portant le transge`ne ipt (ligne´es 101, 102 et 103) en se´lectionnant les plants pour l'insertion d'une copie unique du transge`ne, des caracte`res horticoles acceptables et l'activite´du transge`ne. Les trois ligne´es autogames ont ensuite e´te´e´value´es au champ de 2004 a2 007 en vue d'en pre´ciser la croissance, le rendement et la dure´e de conservation apre`s re´colte, comparativement a`une ligne´e autogame non transge´nique (104) et a`la varie´te´parentale Green King. La variabilite´de la plupart des parame`tres de la croissance ve´ge´tative mesure´s d'une anne´e a`l'autre de´passe la variabilite´observe´e entre les ligne´es. L'autofe´condation agit peu sur l'aspect ou le rendement potentiel des ligne´es de brocoli. Le nomb...

Compositional and Proteomic Analyses of Genetically Modified Broccoli (Brassica oleracea var. italica) Harboring an Agrobacterial Gene

“…Modification in the genome of transgenic plants might cause broad changes in transcriptome, proteome and metabolome. Lines 102 and 103 are 2 independent ipt -transgenic lines with different insertion sites [ 21 ]. Their different genomic modifications resulted in changed protein composition and physiologic features in that postharvest senescence is delayed more with line 103 than line 102 [ 21 ].…”

“…Green King; GK), its fifth generation (T 5 ) inbred line 104 and ipt -transgenic T 5 -inbred lines 101, 102 and 103, containing the agrobacterial ipt gene driven by the senescence-associated SAG-13 promoter [ 21 ]. The transgenic plants were homozygous plants with single T-DNA insertion [ 21 ]. The plants were grown in an isolated field at the Taiwan Agricultural Research Institute (TARI), Wufeng, Taichung, Taiwan.…”

“…Previously, we demonstrated an improvement in delaying postharvest senescence without affecting yield with transgenic isopentenyltransferase ( ipt ) broccoli derived from fifth-generation inbred (selfed-T 5 ) progeny [ 20 , 21 ]. The transgenic ipt mimics the action of N 6 -benzylaminopurine BA that delays postharvest senescence by accumulation of molecular chaperones and stress-related proteins [ 22 , 23 ].…”

Βιοχημική Και Φυσιολογική Διερεύνηση Της Επίδρασης Εξωγενών Κυτοκινινών Στις Διεργασίες Ανάπτυξης Και Ωρίμανσης Καρπών Ακτινιδιάς

“…Σα ζοβηεηνζιέκα εονήιαηα ζοκέααθακ ζηδκ άπμρδ υηζ αολδιέκα επίπεδα ηοημηζκζκχκ ζοκεπάβμκηαζ αολδιέκα επίπεδα αζεοθεκίμο (Woeste et al, 1999), υιςξ πνυζθαηα δεδμιέκα ακηζηνμφμοκ αοηή ηδκ άπμρδ. Γζαβμκζδζαηέξ ζεζνέξ ιπνυημθμο ιε αολδιέκα επίπεδα βμκζδίμο IPT ζηενμφκηακ ημο εκγφιμο μλεζδάζδ-2 ημο 1αιζκμηοηθμπνμπακμ-1-ηαναμλοθζημφ μλέμξ (ACΟ) (Liu et al, 2011), πμο είκαζ απαναίηδημ βζα ημ ηεθεοηαίμ αήια ηδξ αζμζφκεεζδξ ημο αζεοθεκίμο, οπμδεζηκφμκηαξ υηζ ημ βμκίδζμ IPT πμο ζοκδέεηαζ άιεζα ιε ηδ ζοζζχνεοζδ ηοημηζκζκχκ (Chan et al, 2009) ακέζηεζθε ηδ αζμζφκεεζδ ημο αζεοθεκίμο. Ακηζζηνυθςξ, έπεζ ακαθενεεί δ επίδναζδ ημο αζεοθεκίμο ζηδ ζδιαημδυηδζδ ηςκ ηοημηζκζκχκ ελαζηίαξ ηδξ ηαηαζημθήξ ηςκ ARR5, ARR7 ηαζ ARR15 (Shi et al, 2012).…”