Abstract

The plant circadian clock is proposed to provide an adaptive benefit by ensuring the correct diurnal timing of metabolism and the correct seasonal timing of development. Mutational studies in Arabidopsis thaliana support this notion. First I will outline the current clock network, as understood at a molecular-genetic and partial cellular layer of understanding. Then I will discuss the role of natural allelic variation in the clock under controlled and field settings. We examined clock parameters in Arabidopsis mapping populations under simulated field experiments and concluded that the oscillator provides a memory of the preceding environment of thermal and photic cycles. The cellular context of protein products of several natural variants we cloned will be discussed. From there we grew such mapping populations in the field and concluded that the season of germination has a large effect on subsequent clock behavior. This had a large association to predicting survivability and fitness in cohorts compared under contrasting seasons. Relevance of this fitness to agriculture is extended to showing that barley breeders have selected for clock variants, and I will report the identity of several of these domestication genes. The role of the barley clock to provide stress adaptation will also be discussed in a tissue-organizational context.