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FRIBIO2-FRIPRO forskerprosjekt, biologi

Live or let die? Deciphering the developmental and genetic basis for transitions between perenniality and annuality in temperate grasses

Alternative title: Å leve eller å la dø? Genetisk basis for evolusjon av ettårighet i tempererte gress

Awarded: NOK 12.0 mill.

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2020 - 2025


Imagine letting yourself die to avoid a stressful situation, just to return when the situation has calmed. It sounds like magic, but this is essentially what numerous plants do to avoid stressors like drought and frost when they adopt an annual growth habit. The alternative strategy is to adopt coping mechanisms to live through many seasons, referred to as the perennial growth habit. These two strategies require fundamentally different physiology. Annuals have high growth rates, large leaf area, large allocation of resources to reproductive structures and high biomass production. Perennials have traits allowing for persistence and defense, like high tissue density and allocation of higher proportion of biomass into roots. Even with these fundamental differences in growth strategies, the evolutionary distance between annual and perennial species may be very small, indicating that small differences in genetic makeup differentiate the growth habits. However, what these differences are is to a large degree unknown. Due to physiological differences between annuals and perennials, agricultural practices for annual crops put pressure on the sustainability of agricultural systems: the less developed root systems in annuals often make them less efficient in water and nutrient uptake as compared to perennials, they are less resistant to weeds and pests and they need to be sown every year, which require more tillage. Given the demand for increased, but sustainable food production, combining the crop output of an annual with the persistence abilities of a perennial by breeding perenniality into annual crop species would contribute to meet this demand. However, progress in breeding perenniality into annuals is hampered by our limited knowledge about the developmental and genetic mechanisms underlying growth habits. In this project we will decipher the genetic bases for annual and perennial life history strategies and determine how development is influenced by these genes.

Annual plants flower a single time during their one-year life cycle, whereas perennial plants flower multiple times over several years and keep some of their growing parts vegetative to survive from year to year. These two very different life forms are adaptations to different environments. Annuals escape stressful seasonal periods like drought and heat as seeds, whereas perennial species persist stressful periods. Following this, annuals maximise reproductive efforts, whereas perennials divert their energy between reproduction and persistence. Annuals and perennials differ in growth and physiology both in the vegetative and generative phase. Even with fundamental differences in growth strategies, the evolutionary distance between annual and perennial species may be very small, indicating that small differences in genetic makeup differentiate the growth habits. A target family for developing more knowledge about growth habit is the grass family (Poaceae). It is one of the largest food crop families and include the annual species rice, maize, wheat and barley. However, we know very little about the timing of developmental transitions, the physiological architecture of vegetative and generative shoots and the genetics underlying these differences in annual and perennial grass species. In this project, I propose to address this knowledge gap by using a novel, framework where we will study several independent evolutionary origins of annual species to decipher the genetic and physiological bases of annual and perennial growth habits in the Pooideae subfamily of the grasses. The study will integrate new physiological, developmental, genetic, and epigenetic data from a large number of Pooideae species. The expected outcome will be the unravelling of developmental and physiological mechanisms differentiating annual and perennial growth habits in Pooideae and the identification of major genes controlling these differences.


FRIBIO2-FRIPRO forskerprosjekt, biologi