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MULTI-INSTITUTIONAL RESEARCH SHEDS NEW LIGHT ON CIRCADIAN CLOCK GENES

A multi-institutional team led by researchers from OSU (Sergei Filichkin, Jason S. Cumbie, J., Palitha Dharmawadhana, Pankaj Jaiswal, Jeff Chang, and Molly Megraw) and including those from Colorado State University (Saiprasad Palusa and A.S.N. Reddy) and Donald Danforth Plant Science Center (Todd Mockler) discovered new links between alternative splicing of circadian clock genes and regulation of plant responses to environmental stress. The circadian clock is a time-keeping mechanism that allows eukaryotes to anticipate daily fluctuations of environmental cues such as light, temperature, and even optimal times for pathogen infection. In plants, the proper functioning of the circadian clock increases fitness and adaptation to the environment. The central circadian oscillator also orchestrates expression of numerous gene networks in response to biotic and abiotic stresses. The team found that stress-driven alternative splicing of the specific core clock genes triggers the production of mRNAs that do not give rise to functional proteins. However, rather than being degraded by cellular surveillance mechanisms, these mRNAs play an important role in compensating stress-induced instabilities of the central oscillator. Surprisingly, mutants deficient in the surveillance machinery showed pre-activation of some stress-response networks including immunity-associated genes, with decreased susceptibility to bacterial pathogen. These findings provide new insights into the mechanisms of plants adaptation to environmental stresses. This study was published in Molecular Plant (http://www.ncbi.nlm.nih.gov/pubmed/25366180).