Oilseed rape (Brassica napus): the importance of aminopeptidases in germination under normal and heavy metals stress conditions

• Published in: Journal of the science of food and agriculture Vol. 101; no. 15; pp. 6533 - 6541
• Main Authors: Kania, Joanna, Krawczyk, Tomasz, Gillner, Danuta M
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-12-2021; John Wiley and Sons, Limited
• Subjects: Alanine; Amino acids; aminopeptidases; Brassica; Brassica napus; Cadmium; Climatic conditions; Crop yield; Cultivation; Developmental stages; Feed industry; Food; Food industry; Food sources; Gene expression; Germination; germination process; Glycine; Heavy metals; influence of metals; Lead; Leucine; Metal ions; Methionine; Nitrogen; Oilseed crops; oilseed rape; Oilseeds; Organic nitrogen; Osmoprotectants; Phenylalanine; Proline; Rape plants; Rapeseed; Stress; stress factors; Substrates; Oilseed rape; Stress factors; Germination process; Influence of metals; Aminopeptidases
• DOI: 10.1002/jsfa.11325
• EISSN: 1097-0010
• ISSN: 0022-5142

BACKGROUND
Oilseed rape is one of the most important oilseed crops worldwide, crucial in the food and feed industries. Different environment and climatic conditions can influence its sustainable cultivation and crop yield. Aminopeptidases are crucial enzymes in many physiological processes in all organisms, including humans, so it is important to learn their behavior in food and feed sources. This study presents, for the first time, a detailed discussion on the importance of aminopeptidases, during the oilseed rape germination process, under standard and stress conditions.
RESULTS
During the germination of oilseed rape under standard conditions, a significant increase in aminopeptidases activity toward N‐terminal amino acids – phenylalanine (Phe), alanine (Ala), glycine (Gly), leucine (Leu), proline (Pro), methionine (Met) – was observed. The change was substrate specific, with the highest increase being observed for Gly (3.2‐fold), followed by Ala (2.9‐fold), Pro (2.5‐fold), Met (1.5‐fold), and Phe (1.3‐fold). Generally, N‐terminal Phe was preferentially cleaved. Germination under stress conditions, caused by several heavy metal ions (e.g. divalent copper, zinc, cadmium, and lead ions), negatively influenced the plants' growth and quality, but significantly enhanced the expression of genes encoding aminopeptidases (or potentially activated aminopeptidases precursors), which was related to the dramatic increase of their activity.
CONCLUSIONS
The activity/concentration of aminopeptidases in plants is adjusted to the needs at each stage of development and stress factors occurrence. The most significant increase of activity toward N‐terminal Gly and Pro proved the key role of aminopeptidases in the defense mechanisms, by supplying the plants with osmoprotectants and organic nitrogen. The results provide new concepts of oilseed rape growth and cultivation under different conditions. © 2021 Society of Chemical Industry.