Molybdate toxicity in Chinese cabbage is not the direct consequence of changes in sulphur metabolism

A - Papers appearing in refereed journals

Zuidersma, E. I., Ausma, T., Stuiver, C. E. E., Prajapati, D. H., Hawkesford, M. J. and De Kok, L. J. 2019. Molybdate toxicity in Chinese cabbage is not the direct consequence of changes in sulphur metabolism. Plant Biology.

AuthorsZuidersma, E. I., Ausma, T., Stuiver, C. E. E., Prajapati, D. H., Hawkesford, M. J. and De Kok, L. J.
Abstract

In polluted areas, plants may be exposed to supra-optimal levels of the micronutrient molybdenum. The physiological basis of molybdenum phytotoxicity is poorly understood. Plants take up molybdenum as molybdate, which is a structural analogue of sulphate. Therefore, it is presumed that elevated molybdate concentrations may hamper the uptake and subsequent metabolism of sulphate, which may induce sulphur deficiency.
In the current research, Chinese cabbage (Brassica pekinensis) seedlings were exposed to 50, 100, 150 and 200 lM Na2MoO4 for 9 days.
Leaf chlorosis and a decreased plant growth occurred at concentrations ≥100 lM. Root growth was more affected than shoot growth. At ≥100 lM Na2MoO4, the sulphate uptake rate and capacity were increased, although only when expressed on a root fresh weight basis. When expressed on a whole plant fresh weight basis, which corrects for the impact of molybdate on the shoot-to-root ratio, the sulphate uptake rate and capacity remained unaffected. Molybdate concentrations ≥100 lM altered the mineral nutrient composition of plant tissues, although the levels of sulphur metabolites (sulphate, water-soluble non-protein thiols and total sulphur) were not altered. Moreover, the levels of nitrogen metabolites (nitrate, amino acids, proteins and total nitrogen), which are generally strongly affected by sulphate deprivation, were not affected. The root water-soluble non-protein thiol content was increased, and the tissue nitrate levels decreased, only at 200 lM Na2MoO4.
Evidently, molybdenum toxicity in Chinese cabbage was not due to the direct interference of molybdate with the uptake and subsequent metabolism of sulphate.

KeywordsBrassica; Heavy metals; Molybdenum; Sulphate assimilation; Sulphate uptake
Year of Publication2019
JournalPlant Biology
Digital Object Identifier (DOI)doi:10.1111/plb.13065
Open accessPublished as green open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeDesigning Future Wheat - WP1 - Increased efficiency and sustainability
Publisher's version
Accepted author manuscript
Output statusPublished
Publication dates
Online01 Nov 2019
Publication process dates
Accepted19 Oct 2019
PublisherWiley
ISSN1435-8603

Permalink - https://repository.rothamsted.ac.uk/item/97070/molybdate-toxicity-in-chinese-cabbage-is-not-the-direct-consequence-of-changes-in-sulphur-metabolism

6 total views
3 total downloads
4 views this month
3 downloads this month
Download files as zip