Expression of MdCCD7 in the scion determines the extent of sylleptic branching and the primary shoot growth rate of apple trees
Autor: | Ali Saei, Toshi Foster, Susan E. Ledger, Alla N. Seleznyova, Kimberley C. Snowden, Sumathi Tomes, Keith A. Funnell, Chethi N. Waite, Ben M. van Hooijdonk, Sakuntala Karunairetnam, Bart J. Janssen, Zhiwei Luo, Revel S.M. Drummond |
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Jazyk: | angličtina |
Rok vydání: | 2017 |
Předmět: |
0106 biological sciences
0301 basic medicine Physiology Mutant sylleptic branching Plant Science Biology 01 natural sciences Dioxygenases 03 medical and health sciences Lactones Plant Growth Regulators RNA interference Gene Expression Regulation Plant Arabidopsis Axillary bud Botany Malus×domestica shoot growth rate strigolactone CAROTENOID CLEAVAGE DIOXYGENASE (CCD) Plant Proteins fungi Wild type food and beverages Meristem biology.organism_classification Research Papers 030104 developmental biology Malus Shoot Rootstock Plant Shoots 010606 plant biology & botany |
Zdroj: | Journal of Experimental Botany |
ISSN: | 1460-2431 0022-0957 |
Popis: | This is the first case of wild-type roots being unable to suppress branching in a strigolactone-deficient scion. MdCCD7 RNAi primary shoots also exhibited an increased growth rate relative to the wild type. Branching has a major influence on the overall shape and productivity of a plant. Strigolactones (SLs) have been identified as plant hormones that have a key role in suppressing the outgrowth of axillary meristems. CAROTENOID CLEAVAGE DIOXYGENASE (CCD) genes are integral to the biosynthesis of SLs and are well characterized in annual plants, but their role in woody perennials is relatively unknown. We identified CCD7 and CCD8 orthologues from apple and demonstrated that MdCCD7 and MdCCD8 are able to complement the Arabidopsis branching mutants max3 and max4 respectively, indicating conserved function. RNAi lines of MdCCD7 show reduced gene expression and increased branching in apple. We performed reciprocal grafting experiments with combinations of MdCCD7 RNAi and wild-type ‘Royal Gala’ as rootstocks and scion. Unexpectedly, wild-type roots were unable to suppress branching in MdCCD7 RNAi scions. Another key finding was that MdCCD7 RNAi scions initiated phytomers at an increased rate relative to the wild type, resulting in a greater node number and primary shoot length. We suggest that localized SL biosynthesis in the shoot, rather than roots, controls axillary bud outgrowth and shoot growth rate in apple. |
Databáze: | OpenAIRE |
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