How plants can do without light

Light is vital to plants but some species can grow without any photosynthesis. To understand this evolutionary transition, the SPOmics platforms and a team of the Muséum national d'Histoire naturelle (ISYEB) studied mutants of wild orchids lacking chlorophyll but growing spontaneously in the field. In their study published in the Plant Journal, the researchers used high-throughput technologies to measure their gene expression (transcriptomics) and the accumulation of their metabolites (metabolomics). Comparing albinos mutants to their green counterparts from the same populations suggests that the loss of the photosynthetic activity forces these plants to recycle their own tissues and to use the amino acids and sugars brought by the mycorrhizal fungi which colonize their roots. However, this ability to grow without light doesn't rely on a dramatic change of the metabolism of these plants. Rather, this transition is based on the high versatility and plasticity of plant metabolism and on a sufficient inflow of organic nutrient by their mycorrhizal partners.