Dr Mahwish Ejaz

Postdoctoral Scientist Genes in the Environment

Mahwish’s research focuses on understanding of how genes control stem growth and trying to develop more precise genetic tools to increase plant productivity by modifying plant height and shape.

Development of a vertical shoot axis capable of bearing organs above the ground was one of the key steps in the evolution of land plants.

In spite of its ancient and central role in shaping plants, formation of the stem remains one of the least understood processes in plant development. This process also has practical importance: mutations that reduce stem growth have been widely used to improve crop yield but also have undesired side effects on plant growth, for example during seed germination.

One way to develop new tools to modify plant height is to study how genes modulate stem growth at different stages of the plant’s life.

This modulation is seen markedly in plants with a rosette habit, such as Arabidopsis, beet, radish, lettuce and cabbage, in which stem elongation is initially inhibited, but later activated during flowering. This transition is triggered by environmental conditions such as day length and temperature, and initiates growth of the stem in a specific region of the shoot apex, called the rib zone (RZ).

It has been shown that a gene called ATH1 has a key role in controlling elongation: ATH1controls stem initiation by acting as a “gatekeeper” for a hormone signal, gibberellin, that is known to promote stem growth. To test this idea, Mahwish propose to follow how ATH1 affects genes involved in gibberellin signalling.

Another motivation for studying regulatory sequences in ATH1 is that they may play a role in existing diversity in stem growth in vegetable Brassicas, and could be used to create useful, new variation in plant height and shape. Therefore, Mahwish is also exploring the role of ATH1 genetic variation in Brassica architecture.

Overall, this work will reveal the genetic mechanism controlling stem initiation, will shed light on how a variety of plant shapes have been selected during crop breeding, and will produce novel genetic tools to control the height and shape of plants.