Plant ribosomopathies: New insights and a critical re-evaluation of ribosomal protein gene mutants in plants

Ribosomes are essential cellular machines that translate genetic information into functional proteins. Ribosomes require massive nutrient investments, accounting for as much as 50 % of organic phosphorus and 25 % of organic nitrogen in leaves. Optimizing ribosome levels could therefore reduce crop plant fertilizer requirements, an urgent goal for agricultural sustainability. Disruptions to ribosome biogenesis often cause surprising developmental defects, however, and there is substantial confusion and debate among plant geneticists about how to interpret mutant phenotypes caused by defective ribosomes. Here, we propose to adopt the conceptual framework of “ribosomopathies”, human disorders caused by defects in ribosome biogenesis, to better appreciate why some plant developmental processes are more sensitive to ribosome levels than others. We argue that understanding plant ribosomopathies as a broad class of mutants that affect ribosome homeostasis, rather than a series of distinct cases impacting specialized, heterogeneous ribosomes, will encourage productive mechanistic studies of specific ribosome-sensitive developmental processes that could be engineered to circumvent the deleterious effects of restricting ribosome availability.