Aakansha Kanojia

Doctor of Philosophy, (Fundamental Sciences)
Study Completed: 2018
College of Sciences

Citation

Thesis Title
Stress-adapation and ageing is controlled by senescence-inducing age related changes in Arabidopsis thaliana

Ms Kanojia investigated the biological pathways involved in the reduction of plant stress tolerance with age. Using Arabidopsis thaliana, she confirmed that stress susceptibility with age in Arabidopsis leaves is consistent with a role for age related changes (ARCs) in stress resistance. Secondly, she compared the transcriptomes of ageing, excluding senescing individual rosette leaves, by RNA-sequencing. Analysis of differentially expressed genes showed leaf maturation coincides with a marked downregulation of genes involved in DNA repair, while genes involved in stress hormone biosynthesis and signalling, and genes indicative of oxidative stress, were upregulated. This study suggests young plants are more tolerant to stress because of negligible ARCs in young leaves, whereas the gradual and rapid accumulation of ARCs in mature and old leaves result in decreased tolerance to stress. In conclusion, the occurrence of senescence-inducing ARCs is an intrinsic process integrated into the stress response and ensures certain death in plants.

Supervisors
Associate Professor Paul Dijkwel
Mr White
Professor Kathryn Stowell