I am a final year PhD student at the University of Melbourne, Australia. I enjoy applied genetic, physiological and bioinformatic research, and I am motivated to pursue research questions that contribute to tackling global food insecurity. My PhD research has established a connection between circadian rhythms, senescence and nutrient remobilisation in wheat.
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Circadian influence on senescence and nutrition in wheat
C. R. BUCKLEY, A. FOURNIER-LEVEL, M. J. HAYDON
School of BioSciences, University of Melbourne, Parkville, VIC 3010, Australia
The circadian clock plays a key role in regulating the onset of senescence and the dynamics of nutrition in plants. Despite its immense potential contribution to yield-related traits, the wheat (Triticum aestivum) clock has received relatively little research focus. Here, we measured circadian rhythms of elite Australian wheat cultivars and identified a large variation in the clock’s output between genotypes. We show that the cycling pace (period) of these cultivars covaries with the timing of leaf senescence and leaf to grain nutrient mobilisation efficiency. To investigate how the clock might govern these traits, we generated 48-hour ‘circadian transcriptomes’ in mature and senescent wheat flag leaves. The period of rhythmic transcripts shortens by an average of 0.5 h in senescent leaves, akin to observations of ageing in other species. Strikingly, clock genes are significantly enriched amongst a set of transcripts that show little or no change in period with senescence (within ±0.5 h). Instead, clock genes are over-represented among significantly ‘differentially rhythmic’ transcripts, with large phase advances underpinning senescence-associated changes in their expression. These findings highlight untapped functional potential of clock gene variation in wheat and outline a possible genetic basis for the connection between the clock, senescence, and nutrient mobilisation.