In:
Journal of Experimental Botany, Oxford University Press (OUP), ( 2023-10-09)
Abstract:
Drought stress poses a serious threat to wheat grain formation. Nitrogen (N) plays crucial roles in plant organ development. However, the physiological mechanisms by which drought stress affects plant N availability and mediates the formation of grains in spikes of winter wheat are still unclear. Here, we revealed that pre-reproductive drought stress significantly reduced the number of fertile florets and inhibited the formation of grain numbers. Transcriptome analysis demonstrated that this was related to N metabolism, arginine (main precursor for polyamine (PA) synthesis) and proline metabolism pathways. Continuous drought stress restricted plant N accumulation and reallocation rates, but plants preferentially allocated more N to spike development. However, as the activities of amino acid biosynthesis enzymes and catabolic enzymes were inhibited, more free amino acids accumulated in young spikes. Unfortunately, the expression of PA synthase genes was downregulated, and catabolic enzyme-encoding gene expression was enhanced under drought stress, resulting in reductions in endogenous spermidine and putrescine. Importantly, exogenous spermidine treatment optimized N allocation in young spikes and leaves, which greatly alleviated adverse effects reducing the number of grains per spike. Overall, pre-reproductive drought stress affected wheat grain numbers by regulating N redistribution and PA metabolism.
Type of Medium:
Online Resource
ISSN:
0022-0957
,
1460-2431
Language:
English
Publisher:
Oxford University Press (OUP)
Publication Date:
2023
detail.hit.zdb_id:
1466717-4
SSG:
12
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