Pencik, Ales
- Institutionen för skoglig genetik och växtfysiologi, Sveriges lantbruksuniversitet
Sammanfattning
Phytohormone homeostasis is essential for proper growth and development of plants. To understand the growth mechanisms mediated by hormonal levels, we isolated a gulliver1 (gul1) mutant that had tall stature in the presence of both brassinazole and the light. The gul1 phenotype depended on functional BR biosynthesis; the genetic introduction of dwarf4, a BR biosynthetic mutation, masked the long hypocotyl phenotype of gul1. Furthermore, BR biosynthesis was dramatically enhanced, such that the level of 22-hydroxy campesterol was 5.8-fold greater in gul1. Molecular cloning revealed that gul1 was a missense mutation, resulting in a glycine to arginine change at amino acid 116 in SUPERROOT2 (CYP83B1), which converts indole acetaldoxime to an S-alkyl thiohydroximate adduct in the indole glucosinolate pathway. Auxin metabolite profiling coupled with quantitative reverse transcription polymerase chain reaction (RT-PCR) analysis of auxin biosynthetic genes revealed that gul1/sur2-7 activated multiple alternative branches of tryptophan-dependent auxin biosynthetic pathways. Furthermore, exogenous treatment of gul1/sur2-7 with BRs caused adventitious roots from hypocotyls, indicative of an increased response to BRs relative to wild-type. Different from severe alleles of sur2, gul1/sur2-7 lacked high-auxin' phenotypes that include stunted growth and callus-like disintegration of hypocotyl tissues. The auxin level in gul1/sur2-7 was only 1.6-fold greater than in the wild-type, whereas it was 4.2-fold in a severe allele like sur2-8. Differences in auxin content may account for the range of phenotypes observed among the sur2 alleles. This unusual allele provides long-sought evidence for a synergistic interaction between auxin and BRs in promoting growth in Arabidopsis at the level of their biosynthetic enzymes.
Nyckelord
Arabidopsisthaliana; brassinazole; cytochrome P450; whole genome resequencing; picloram
Publicerad i
Plant Journal
2014, volym: 80, nummer: 5, sidor: 797-808
Utgivare: WILEY-BLACKWELL
SLU författare
Ljung, Karin
- Institutionen för skoglig genetik och växtfysiologi, Sveriges lantbruksuniversitet
- Institutionen för skoglig genetik och växtfysiologi, Sveriges lantbruksuniversitet
UKÄ forskningsämne
Genetik och förädling inom lantbruksvetenskap
Botanik
Publikationens identifierare
- DOI: https://doi.org/10.1111/tpj.12678
Permanent länk till denna sida (URI)
https://res.slu.se/id/publ/67585