Research School of Biology, ANU Joint College of Sciences, Australian National University, Canberra, Australian Capital Territory, Australia.
Biomedical Centre, University of Colima, Colima, Mexico.
Plant Cell Environ. 2020 Jun;43(6):1331-1347. doi: 10.1111/pce.13740. Epub 2020 Feb 19.
Biomarker metabolites are of increasing interest in crops since they open avenues for precision agriculture, whereby nutritional needs and stresses can be monitored optimally. Putrescine has the potential to be a useful biomarker to reveal potassium (K ) deficiency. In fact, although this diamine has also been observed to increase during other stresses such as drought, cold or heavy metals, respective changes are comparably low. Due to its multifaceted biochemical properties, several roles for putrescine under K deficiency have been suggested, such as cation balance, antioxidant, reactive oxygen species mediated signalling, osmolyte or pH regulator. However, the specific association of putrescine build-up with low K availability in plants remains poorly understood, and possible regulatory roles must be consistent with putrescine concentration found in plant tissues. We hypothesize that the massive increase of putrescine upon K starvation plays an adaptive role. A distinction of putrescine function from that of other polyamines (spermine, spermidine) may be based either on its specificity or (which is probably more relevant under K deficiency) on a very high attainable concentration of putrescine, which far exceeds those for spermidine and spermine. putrescine and its catabolites appear to possess a strong potential in controlling cellular K and Ca , and mitochondria and chloroplasts bioenergetics under K stress.
生物标志物代谢物在作物中越来越受到关注，因为它们为精准农业开辟了途径，通过这种途径可以最佳地监测营养需求和压力。腐胺有可能成为一种有用的生物标志物来揭示钾（K）缺乏。事实上，尽管这种二胺也被观察到在其他压力下增加，如干旱、寒冷或重金属，各自的变化相对较低。由于其多方面的生化特性，腐胺在 K 缺乏下的几种作用已经被提出，例如阳离子平衡、抗氧化剂、活性氧物质介导的信号转导、渗透调节剂或 pH 调节剂。然而，腐胺积累与植物中低 K 供应之间的具体关联仍知之甚少，可能的调节作用必须与植物组织中发现的腐胺浓度一致。我们假设，K 饥饿时腐胺的大量增加起着适应性作用。腐胺功能与其他多胺（精胺、亚精胺）的区别可能基于其特异性，或者（在 K 缺乏下可能更相关）基于腐胺可达到的非常高的浓度，远远超过精胺和亚精胺的浓度。腐胺及其代谢物似乎在控制细胞内 K 和 Ca 以及线粒体和叶绿体生物能学方面具有很大的潜力。
