ISHS Acta Horticulturae 773: XXVII International Horticultural Congress - IHC2006: International Symposium on Citrus and Other Tropical and Subtropical Fruit Crops
MORPHOGENESIS CONTROL OF MULBERRY 'GARYU' AND TRIFOLIATE ORANGE 'HIRYU' |
| Authors: | T. Sopian, G. Gulyás, F. Jiao, Y. Hirata |
| Keywords: | citrus, bending stem, dwarf, GA, PCR, Morus spp. |
| Abstract:
Trifoliate orange (Poncirus trifoliate) is a known parent used to create dwarf rootstocks in citrus. Mulberry (Morus spp.) has more than 1,300 germplasm accessions in Japan, several mutant types also exist, including ‘Garyu’ which is similar to trifoliate orange ‘Hiryu’ in its bending stem character. Development analysis of mulberry ‘Garyu’ and trifoliate orange ‘Hiryu’ was carried out in order to characterize bending stem and dwarf characteristics in these woody plants. We also designed hormone treatment experiments on both plant materials by using gibberellin (GA3), natural abscisic acid (S-(+)-ABA) and the mixture of both hormones (GABA) to obtain responses. Further, we confirmed these results with genetic analysis of known hormone related genes to find out whether bending character had any relationship with hormonal control. We found that mulberry ‘Garyu’ and trifoliate orange ‘Hiryu’ had similar characters. Both plant materials grew with a relatively short internodal distance and the bending stem character near the shoot apex became much more extreme. Observation on bud histology, using the paraffin embedded sections, showed that the bending stem in mulberry could be observed from an early developmental stage. Hormone treatment experiments revealed that both plant materials did not respond to these hormone treatments, contrary to their wild types. Through pGEM-T vector-mediated cloning of PCR products using GAI and BRI1 degenerate primers, we cloned a 800 bp GAI-like gene fragment from mulberry ‘Kokuso 16’ and a 500 bp BRI1-like gene fragment from mulberry ‘Garyu’. Sequence results of GAI-like revealed that at least 250 bp sequenced nucleotides had 86% homology to RGA1, repressor of GA1-3 1 mutant related to gibberellin function of Arabidopsis; and the result of BRI1-like showed that sequenced nucleotides had 85% homology to Mangifera indica putative LRR protein gene, the conserved region of brassinosteroids insensitive genes motifs. | |
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