Table 5_Cross-species transcriptomics and transgenic analyses implicate major LHCII genes in microalgal responses to ammonium stress.docx

Although ammonium stress has been widely documented, the conserved response modules shared by microalgae and higher plants remain poorly understood.</p>Methods<p>We performed a cross-species transcriptomic comparison using Auxenochlorella pyrenoidosa, Chlamydomonas reinhardtii and rice (Oryza sativa) to identify conserved pathways associated with ammonium stress.

To test its functional relevance, we generated overexpression lines of the major LHCII gene in A. pyrenoidosa and C. reinhardtii.</p>Results<p>The photosynthesis-antenna protein pathway was detected in all three species and significantly enriched in C. reinhardtii and rice, and major LHCII antenna genes were consistently downregulated under ammonium stress. Under ammonium stress, overexpression of the major LHCII gene improved algal performance in both species, but the dominant beneficial traits differed: increased cell density and chlorophyll accumulation in A. pyrenoidosa, and increased fresh weight together with improved chlorophyll accumulation in C. reinhardtii.