The plant hormone auxin is very crucial for regulating plant growth and development. The shape of the plant as well as the function of tissues and cells is controlled by auxin. It acts on cell division, elongation and differentiation and directs like this for example the growth of a plant towards the light. The spatial distribution of auxin within the plant is very inhomogeneous to allow this directed growth. It is regulated by complex interactions between different pathways for auxin transport, signalling and metabolism.

Three mechanisms control auxin metabolism: auxin biosynthesis, degradation and conjugation, i.e. the binding of auxin to amino acids or sugars. Enzymes involved in biosynthesis and conjugation of auxin are already well characterised but little was known about the enzyme which catalyses the degradation of auxin by oxidation. The three PNAS articles show for the first time that DAO1 (dioxygenase for auxin oxidation 1) is the functional auxin oxidising enzyme in Arabidopsis and they provide altogether a very detailed characterisation of this enzyme.

The team around Karin Ljung from the Umeå Plant Science Centre (UPSC) could show that mutants with reduced DAO1 activity have increased levels of auxin conjugates. These conjugates are considered to be storage forms of auxin with low biological activity. The researchers concluded that the missing function of DAO1 for inactivating auxin is compensated by an increased activity of auxin conjugating enzymes. This is important for keeping the auxin homeostasis balanced.

The groups of Markus Owen and Malcolm Bennett from Nottingham University chose a systems biology approach. They developed in cooperation with Karin Ljung’s group a mathematical model of auxin metabolic pathways based on experimental data. The researchers predicted with the help of their model that the auxin concentration in the DAO1 mutant is elevated in a special zone in the root tip. The root hairs in this mutant were longer than normal and the prediction gave the explanation for these findings.

Since several years, Stefan Jansson, professor at the Umeå Plant Science Centre (UPSC) and at Umeå University, is very active in discussing questions about GMO (genetically modified organisms). The recent development of gene editing methods like CRISPR-Cas9 breathed new life into this GMO discussion.  

CRISPR (clustered regularly interspaced short palindromic repeats)-Cas9 allows either to exchange one part of a gene by another DNA fragment or to cut a segment out. The cabbage plant grown this summer in Stefan’s garden was modified in the latter way, i.e. a segment of the DNA was removed but no “foreign DNA” introduced.  

The Swedish Board of Agriculture decided in November 2015 that plants modified with this new technique by which defined parts of the DNA are cut out of the genome are not considered to fall under the GMO-legislation. This decision allowed Stefan Jansson to grow the modified cabbage plants legally in his garden. He has blogged about his unique summer gardening experiences in the “Forskarbloggen” at Umeå University. 

[2016-08-26] The UPSC PhD and Postdoc Retreat 2016 took place last week in Skeppsvik Herrgård, close to Umeå. During two days the PhD students and Postdocs discussed their research, learned about advanced scientific techniques and had some career training. The feedback was overall very positive and the interest is high to make it to an annually repeating event. 

One intention for initiating a UPSC PhD and Postdoc Retreat was to offer training related to career development. The emphasis this year was on exercising the job interview situation. HR officer and job coach Maria Rönnholm discussed with the participants what is important before, during and after a job interview and she simulated a job interview situation. 

The other main focus of this year’s retreat was to strengthen the PhD and Postdoc network within the UPSC. The organisers created a program that consisted not only of scientific sessions but also included team building activities and some free time for social activities and discussions. About 35 people participated and their responses were throughout positive: “It was a really good mix of technical, scientific and career training and fun”, as one of the participants summarised the two exciting days. 

The first day started with the presentation of the individual research projects. Every participant got two minutes’ time to explain his/her project to the others using a hand-drawn poster. “Many of us were first very sceptical when we heard what we were supposed to do”, said another participant. “But then it turned out to be really interesting and the time passed by very fast.”