Light-Harvesting Antenna Complex and Its Role in Environmental Stress

Abstract

Photosynthesis is an extremely efficient photochemical process. In photosynthetic process, the light-harvesting antenna complex (LH or LHC), also known as antenna complex, is a very important integral component. The photosynthesis begins with photons absorption through the antenna molecules, resulting in the excitation of chlorophyll molecules. The LHC transfers the energy to a chlorophyll a molecule at the photosystem reaction center. However, the LHC gets reorganized in response to various environmental stress factors. For instance, under extreme high-light conditions, various plants and algae adopt “molecular strategies” to activate thermal dissipation of the excess energy for the protection of the photosynthetic system from getting damaged. Similarly, when exposed to iron deficiency, the LHC complex declines functional association with the photosystem I (PSI) core to protect the later. Many plants respond to drought conditions by downregulating the light-harvesting Chl-proteins, thereby reducing the light absorption by antennae complex and the electron transport rates of PSI and photosystem II. Initiating with a brief discussion on important concepts of photochemistry, this chapter intends to visualize the mechanism of the LHCs and portray their response under environmental stress.