Identification and expression analysis of four light harvesting-like (Lhc) genes associated with light and desiccation stress in Ulva linza

The marine alga Ulva linza inhabits the intertidal zone, where it is strongly influenced by different kinds of physical stress, such as high light and desiccation. To cope with these stress conditions, U. linza has evolved stress tolerance strategies to protect against high light-induced photodamage. In the present work, we identified four light harvesting complex (Lhc)-like genes (ElipL1, ElipL2, Cbrx and OHP), which encode proteins that are relatives of light-harvesting complex proteins in U. linza. The mRNA levels of the four genes increased and reached maximum within 3 h under high light, and then rapidly returned to a low level. By contrast, these four genes displayed their highest expression levels at 6 h under desiccation stress. Up-regulation of Cbrx was more significant than the other three genes under both conditions. When compared with the mRNA expression data, the protein levels were not consistent, showing a slight delay under both conditions. These results suggested putative photoprotection functions for ElipL1, ElipL2, Cbrx and OHP in U. linza under both high light and desiccation stresses.