Journal Article

Expression of thioredoxins <i>f</i> and <i>m</i>, and of their targets fructose‐1,6‐bisphosphatase and NADP‐malate dehydrogenase, in pea plants grown under normal and light/temperature stress conditions

Eduardo A. Pagano, Ana Chueca and Julio López‐Gorgé

in Journal of Experimental Botany

Volume 51, issue 348, pages 1299-1307
Published in print July 2000 | ISSN: 0022-0957
Published online July 2000 | e-ISSN: 1460-2431 | DOI: http://dx.doi.org/10.1093/jexbot/51.348.1299
Expression of thioredoxins f and m, and of their targets fructose‐1,6‐bisphosphatase and NADP‐malate dehydrogenase, in pea plants grown under normal and light/temperature stress conditions

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Thioredoxins (Trxs) f and m, as well as their targets chloroplast fructose‐1,6‐bisphosphatase (FBPase) and NADP+‐malate dehydrogenase (NADP‐MDH), displayed transcriptional expression in both photosynthetic and non‐photosynthetic organs of pea plants (Pisum sativum L. cv. Lincoln) grown for 50 d under normal irradiance. However, whereas Trx m and both target enzymes were poorly expressed in non‐photosynthetic tissues, the content of the precursor form of the Trx f‐specific mRNA was high in pea roots. In contrast, the translational expression of Trx f was low in this organ. The high FBPase activity in immature seeds, and the low activity of leaves, must be related to high starch synthesis in the first, and with high sucrose formation in the second. The transcriptional expression of FBPase and NADP+‐MDH, and to a lesser extent that of Trxs f and m, was inhibited under low irradiance in plants grown under both normal and high temperatures. Pea plants grown at low temperature displayed a high level of mRNAs for Trxs and their targets, especially when the growth was carried out at low light. To a lesser extent, similar behaviour was observed at the protein level. Chloroplasts of mesophyll leaf cells of pea plants grown under saturating light, or under sub‐saturating continuous irradiance, showed broken envelopes, distorted structural elements and disorganized starch grains, as a consequence of a photobleaching process and high starch accumulation.

Keywords: Thioredoxins; FBPase; light; temperature; stress; pea plants.; FBPase, fructose‐1,6‐bisphosphatase; NADP‐MDH, NADP+‐dependent malate dehydrogenase; PCR, polymerase chain reaction; RT, reverse transcription; Trx, thioredoxin.

Journal Article.  5880 words.  Illustrated.

Subjects: Plant Sciences and Forestry

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