Rht18 semi-dwarfism in wheat is due to increased GA2oxA9 expression
Date
8 May 2018, Tuesday
Time and Venues
| Venues | Local Time | Time Zone |
| Adelaide Waite Campus – B101-FG-R00-SmallWICWest | 12:00 pm | ACST |
| Armidale – B55-FG-R00-Small | 12:30 pm | AEST |
| Brisbane St Lucia QBP – Level 3 South telepresence room (3.323) | 12:30 pm | AEST |
| Canberra Black Mountain – Discovery Lecture Theatre; Crace – Bld44- Meeting Room 3 | 12:30 pm | AEST |
| Narrabri Myall Vale – Conference Room | 12:30 pm | AEST |
| Perth Floreat – B1b Boardroom | 10:30 am | AWST |
| Hobart Sandy Bay – River View Room | 12:30 pm | AEST |
| Toowoomba – Room TBA | 12:30 pm | AEST |
| Werribee (Melbourne) – Peacock Room | 12:30 pm | AEST |
Speaker
Dr Brett Ford, CSIRO Agriculture and Food
Synopsis
Semi-dwarfing genes have improved crop yield by reducing height, improving lodging resistance, and allowing plants to allocate more assimilates to grain growth. In wheat, the ‘green revolution’, Rht-B1b and Rht-D1b semi-dwarfing alleles, dramatically increased wheat yields but also negatively impact other traits such as coleoptile length and early vigour. It would be desirable to identify alternate semi-dwarfing alleles that deliver the benefits of reduced height but without the negative pleiotropic effects. The Rht18 semi-dwarfing gene has been shown to have good agronomic potential and is a possible alternative to Rht-B1b and Rht-D1b. The casual gene underlying Rht18 was identified by mutagenizing the semi-dwarf durum cultivar Icaro (Rht18) and generating mutants with a range of tall phenotypes. Isolating and sequencing chromosome 6A of these ‘overgrowth’ mutants showed that they contained independent mutations in the coding region of the gibberellic acid (GA), metabolic enzyme, GA2oxA9. GA is a key regulator of plant height and GA2oxA9 is predicted to encode a GA 2-oxidase that metabolises biosynthetic intermediates into inactive products, effectively reducing the amount of bioactive GA. Furthermore, Icaro (Rht18) showed higher expression of GA2oxA9 and lower GA content compared with its tall parent, indicating that increased expression of GA2oxA9 leads to lower GA content and reduced plant height. This work has provided a better understanding of the molecular basis of semi-dwarfing in Rht18, highlighted new strategies to manipulate height and produced a suit of novel alleles that may have advantages of existing semi-dwarfing alleles.
About the speaker
In 2007 I completed a Bachelor of Science degree at La Trobe University in Melbourne. In 2008 I was awarded a GRDC undergraduate scholarship to study the genetics of abiotic stress and salt tolerance in Canola and in 2009 I was awarded a GRDC post graduate scholarship to continue this work. I completed my PhD in 2013 and then started at CSIRO on an OCE postdoctoral fellowship with Megan Hemming and Ben Trevaskis investigating molecular networks controlling wheat and barley development at high temperature. Currently, I’m working with Wolfgang Spielmeyer on my second OCE post doc investigating growth regulating genes in wheat. Last year I was nominated for an Agriculture and Food Breakthrough Innovation award for our work utilising next generation sequencing technologies to fast track gene discovery in wheat.
This is a public seminar.
Open-access to The CSIRO Discovery Theatre @ Black Mountain