What is the role of putrescine accumulated under potassium deficiency?

Abstract

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 2+ , and mitochondria and chloroplasts bioenergetics under K + stress. K E Y W O R D Sdeficiency, ion balance, polyamines, potassium, putrescine

Metabolic Responses to Waterlogging Differ between Roots and Shoots and Reflect Phloem Transport Alteration in Medicago truncatula

“…This suggests that there was an increase in polyamines biosynthesis, which was perhaps associated with the urea cycle (urea was not significantly increased in roots under our conditions). Polyamines play a role in tolerance against abiotic stress, including hypoxia [ 39 , 40 , 41 ]. In addition, it has been proposed that the involvement of amino acid metabolism and polyamines under waterlogging could reflect an aspartate cycle [ 26 ], whereby arginine synthesis would represent a source of fumarate (citrulline + aspartate →→ arginine + fumarate), consumes reducing equivalents, and might be degraded to NO.…”

Putrescine metabolism modulates the biphasic effects of brassinosteroids on canola and Arabidopsis salt tolerance

“…PAs are acknowledged regulators of plant stress responses, and Spd and Spm are generally considered to play more important roles than Put (Liu, Wang, Wu, Gong, & Moriguchi, 2015). Whereas, Put has specific functions that differ from those of Spd and Spm in countering abiotic stresses, such as potassium deficiency (Cui, Pottosin, Lamade, & Tcherkez, 2020). Overexpression of ADC , an arginine decarboxylase gene encoding a key enzyme involved in Put synthesis, can improve stress tolerance of plants, but it should be considered that toxic effects of Put over‐production have also been observed, and the deleterious effects may be caused by enhanced DAO activity and excessive ROS production (Cui et al, 2020).…”

“…Whereas, Put has specific functions that differ from those of Spd and Spm in countering abiotic stresses, such as potassium deficiency (Cui, Pottosin, Lamade, & Tcherkez, 2020). Overexpression of ADC , an arginine decarboxylase gene encoding a key enzyme involved in Put synthesis, can improve stress tolerance of plants, but it should be considered that toxic effects of Put over‐production have also been observed, and the deleterious effects may be caused by enhanced DAO activity and excessive ROS production (Cui et al, 2020). Here, we found that exogenous EBL can promote the accumulation of Spd and Spm, but decrease the level of Put, and the transformation of Put to Spd and Spm was beneficial to plant salt tolerance; however, when plants did not require large amounts of BR under low‐salt stress, excessive application of EBL promoted Put oxidation, and produced large amounts of H 2 O 2 , which harmed plants.…”

Sintomas de deficiência de macronutrientes em alface

“…Com a evolução da carência em K, essas manchas aumentaram de tamanho, no sentido da nervura principal, coalescem e atingiram a maior parte da área foliar, cujo tecido, posteriormente, necrosou (Figura 8). Essa necrose é causada pelo acúmulo da putrescina (Mengel, 2007;Prado, 2008;Hawkesford et al, 2012), a qual em nível tóxico induz a oxidação enzimática de compostos fenólicos pelas enzimas peroxidase e polifenol oxidase, o que resulta no escurecimento de tecidos vegetais (Whitehead & Swardt, 1982;Cui et al, 2020). Sintomas semelhantes foram observados por Casas & Casas (1999) e Rincón (2005), mas diferentes aos encontrados por Almeida et al (2011).…”