Disruption of thylakoid-associated kinase 1 leads to alteration of light harvesting in arabidopsis

To survive fluctuations in quality and intensity of light, plants and algae are able to preferentially direct the absorption of light energy to either one of the two photosystems, PSI or PSII. This rapid process is referred t o as a state transition and has been correlated with the phosphorylation an d migration of the light-harvesting complex protein (LHCP) between PSII and PSI. We show here that thylakoid protein kinases (TAKs) are required for s tate transitions in Arabidopsis. Antisense TAK1 expression leads to a loss of LHCP phosphorylation and a reduction in state transitions. Preferential activation of PSII causes LHCP to accumulate with PSI, and TAK1. mutants di srupt this process. Finally, TAKs also influence the phosphorylation. of mu ltiple thylakoid proteins.