Dr. Öğr. Üyesi Steven Footitt
Moleküler Biyoloji ve Genetik
Kuzey Park, 320
34342 Bebek - Istanbul
+90 (212) 359 6880
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en son düzenleme tarihi: 29.07.2022
Seeds as environmental sensors.
Plants as sessile organisms have evolved strategies to tolerate and survive periodic episodes of environmental stress, such as extremes of temperature and drought. Natural selection drove the development of both adaptive behaviour and environmental sensing mechanisms that help plants tolerate or avoid such conditions. An example of the latter is the cessation of growth following induction of bud dormancy seen in many plants during the winter season.
Seeds also use dormancy to time seedling emergence for when conditions are optimal for seedling establishment. During their development and maturation, seeds sense their environment and receive environmental signals from the mother plant. Both of which contribute to the initial level of seed dormancy present when seeds are shed by the mother plant.
On shedding into the field environment, seeds enter the “seed bank” a reserve of seeds that distributes seedling emergence across years so buffering the population against extreme events. In the seed bank, they are likely to be beneath the soil surface. It is here that seeds have adapted to be highly tuned environmental sensors. This has involved the co-opting of the circadian clock and regulators of flowering time to the regulation of dormancy and germination. This allows them to track changes in temperature over the annual seasonal cycle in order to adjust the level of dormancy so it is at its lowest when conditions are favourable for germination and seedling establishment. This results in seasonally distinct differences between the Abscisic acid (ABA) and Gibberellic acid (GA) signalling pathways that regulate dormancy. In addition, their sensitivity to the environmental signals light and nitrate are determined by the dormancy cycle.
Using natural variation to investigate climate adaptation.
Evolution has adapted plants to the environment of their immediate climate. This has led to an enormous amount of natural variation that enables members (ecotypes) of the same species to time their life cycles to different times of the year. The result is some ecotypes exhibit obligate winter or summer annual life cycles where seedling emergence and flowering are at different times of year. Temperature drove many of these adaptations but other adaptation also led to different sensitivities to light and nitrate; key environmental signals for germination and seedling establishment.
In the seed biology lab, we use natural variation in Arabidopsis and other species to study the molecular eco-physiology of seed behaviour in the natural environment. We are interested in how adaptation to diverse environments has altered responses to temperature, light, and nitrate. Understanding these adaptations will help us predict the responses and adaptability of native flora to climate change. Additionally, identification of allelic variation in genes underlying these traits has the potential to enhancing the resilience of agricultural systems and food security.
- Footitt, S., Walley, P.G., Lynn, J.R., Hambidge, A.J., Penfield, S. and Finch‐Savage, W.E., 2019.
Trait analysis reveals DOG1 determines initial depth of seed dormancy, but not changes during dormancy cycling that result in seedling emergence timing.
New Phytologist, doi: 10.1111/nph.16081
- Finch-Savage, W.E. and Footitt, S., 2017.
Seed dormancy cycling and the regulation of dormancy mechanisms to time germination in variable field environments.
Journal of Experimental Botany, 68(4), pp.843-856.
- Waterworth, W.M., Footitt, S., Bray, C.M., Finch-Savage, W.E. and West, C.E., 2016.
DNA damage checkpoint kinase ATM regulates germination and maintains genome stability in seeds.
Proceedings of the National Academy of Sciences, 113(34), pp.9647-9652.
- Footitt, S., Douterelo-Soler, I., Clay, H. and Finch-Savage, W.E., 2011.
Dormancy cycling in Arabidopsis seeds is controlled by seasonally distinct hormone-signaling pathways.
Proceedings of the National Academy of Sciences, 108(50), pp.20236-20241.
- Footitt, S., Slocombe, S.P., Larner, V., Kurup, S., Wu, Y., Larson, T., Graham, I., Baker, A. and Holdsworth, M., 2002.
Control of germination and lipid mobilization by COMATOSE, the Arabidopsis homologue of human ALDP.
The EMBO Journal, 21(12), pp.2912-2922.