Low temperature stress during the reproductive phase of wheat (Triticum aestivum L.) is a major constraint on yield. The anther connective stage, which governs spikelet differentiation, is particularly susceptible to low-temperature injury. However, the mechanisms by which low temperature at this stage impairs spike development and reduces yield are poorly understood. In this study, we found that low temperature stress during the anther connective stage significantly reduced yield, primarily by increasing spikelet abortion at both the basal and apical regions of the spike. Metabolomic profiling revealed that low temperature stress reprogrammed linoleic acid metabolism, α-linolenic acid metabolism, the citrate cycle, and the pentose phosphate pathway across different wheat organs. Spatial metabolomic profiling further showed a more pronounced activation of linoleic acid and α-linolenic acid metabolism, along with weaker carbohydrate metabolism, in basal spikelets compared with central spikelets. Transcriptomic analysis indicated that genes including LOX1.1, OPR11, PFK3, TKL-2, and G6PDH were upregulated under low temperature conditions. Notably, basal spikelets exhibited higher expression of LOX1.1 than central spikelets, whereas the upregulation of TKL-2 and G6PDH was comparatively weaker. Functionally, exogenous application of methyl jasmonate alleviated yield reduction by balancing carbohydrate distribution, whereas inhibition of the pentose phosphate pathway exacerbated assimilate imbalance. In conclusion, the modulation of linoleic acid and α-linolenic acid metabolism, along with the activation of the pentose phosphate pathway, mitigated wheat yield reduction under low temperature stress by optimizing assimilate allocation within the spike.
Dai et al. (Sun,) studied this question.