Low levels of ribosomal RNA partly account for the very high photosynthetic phosphorus‐use efficiency of Proteaceae species

• Published in: Plant, cell and environment Vol. 37; no. 6; pp. 1276 - 1298
• Main Authors: SULPICE, RONAN, ISHIHARA, HIROFUMI, SCHLERETH, ARMIN, CAWTHRAY, GREGORY R, ENCKE, BEATRICE, GIAVALISCO, PATRICK, IVAKOV, ALEXANDER, ARRIVAULT, STÉPHANIE, JOST, RICARDA, KROHN, NICOLE, KUO, JOHN, LALIBERTÉ, ETIENNE, PEARSE, STUART J, RAVEN, JOHN A, SCHEIBLE, WOLF‐RÜDIGER, TESTE, FRANÇOIS, VENEKLAAS, ERIK J, STITT, MARK, LAMBERS, HANS
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Science 01.06.2014; Blackwell; Wiley Subscription Services, Inc; BlackWell Publishing Ltd
• Subjects: Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis - physiology; Arabidopsis thaliana; Australia; Banksia; Biological and medical sciences; carbon metabolism; chlorophyll; Chlorophyll - metabolism; delayed greening; Enzymatic activity; enzyme activity; enzymes; Fundamental and applied biological sciences. Psychology; glucose; glucose 6‐phosphate; Glucose-6-Phosphate - metabolism; habitats; Hakea; leaves; Original; Phosphorus; Phosphorus - metabolism; Photosynthesis; Plant Leaves - genetics; Plant Leaves - metabolism; Plant Leaves - physiology; Plant Proteins - metabolism; PPUE; Proteaceae; Proteaceae - genetics; Proteaceae - metabolism; Proteaceae - physiology; Ribosomal Proteins - metabolism; ribosomal RNA; ribosomes; RNA, Plant - metabolism; RNA, Ribosomal - metabolism; Rubisco; shikimate dehydrogenase; soil; Starch - metabolism; Australia; Phosphates; Ribulose-bisphosphate carboxylase; Greening; Rubisco; Lyases; Glucose; Banksia; Shikimate 5-dehydrogenase; delayed greening; shikimate dehydrogenase; Ribosomal RNA; Carboxy-lyases; Dicotyledones; Angiospermae; Species; carbon metabolism; Enzyme; Nutrient recovery; Plant ecology; Phosphorus; Proteaceae; Hakea; Metabolism; Carbon; Carbon-carbon lyases; PPUE; glucose 6-phosphate; Spermatophyta; Level; Oxidoreductases; Photosynthesis
• ISSN: 0140-7791; 1365-3040; 1365-3040
• DOI: 10.1111/pce.12240

Proteaceae species in south‐western Australia occur on phosphorus‐ (P) impoverished soils. Their leaves contain very low P levels, but have relatively high rates of photosynthesis. We measured ribosomal RNA (rRNA) abundance, soluble protein, activities of several enzymes and glucose 6‐phosphate (Glc6P) levels in expanding and mature leaves of six Proteaceae species in their natural habitat. The results were compared with those for Arabidopsis thaliana. Compared with A. thaliana, immature leaves of Proteaceae species contained very low levels of rRNA, especially plastidic rRNA. Proteaceae species showed slow development of the photosynthetic apparatus (‘delayed greening’), with young leaves having very low levels of chlorophyll and Calvin–Benson cycle enzymes. In mature leaves, soluble protein and Calvin–Benson cycle enzyme activities were low, but Glc6P levels were similar to those in A. thaliana. We propose that low ribosome abundance contributes to the high P efficiency of these Proteaceae species in three ways: (1) less P is invested in ribosomes; (2) the rate of growth and, hence, demand for P is low; and (3) the especially low plastidic ribosome abundance in young leaves delays formation of the photosynthetic machinery, spreading investment of P in rRNA. Although Calvin–Benson cycle enzyme activities are low, Glc6P levels are maintained, allowing their effective use.