Differential Association of Free, Conjugated, and Bound Forms of Polyamines and Transcript Abundance of Their Biosynthetic and Catabolic Genes During Drought/Salinity Stress in Tomato (Solanum lycopersicum L.) Leaves

Abstract

Polyamines have been implicated in ameliorating the detrimental effects of drought and saline conditions on plant growth and development. The independent impact of these two abiotic stresses on polyamine (PA) biosynthesis, catabolism, and homeostasis, as well as on their transcript abundance in tomato leaves, is presented here. We show that the total levels of putrescine (PUT), spermidine (SPD), and spermine (SPM) increase up to 72 h during drought and up to 48 h during salinity stress before their precipitable drop thereafter. Thus, tomato plants maintain survivability to drought as well as salinity stress for up to 3 and 2 days, respectively. Independent multivariant analyses of drought and salinity stress kinetic data separately showed a closer association with levels of free, conjugated, and bound forms of SPD and SPM, but not with free or bound PUT. However, combined multivariant analyses showed a closer association of free SPD, conjugated SPD, and bound SPD with both stresses; SPD-bound and SPM conjugated with drought; and free SPM and conjugated PUT with salinity stress, respectively. PA biosynthesis genes, ARG1, SPDS1, and SAMDc3, segregated with drought and SPDS2 with salinity stress. PA catabolic genes CuAO4-like and PAO4 were associated with drought and salinity stresses, respectively, suggesting differential involvement of PA biosynthesis and catabolic genes in drought and salinity stresses. Pearson correlation indicated mostly positive correlations between the levels of free, conjugated, and bound forms of PUT, SPD, and SPM under drought and salinity stress. However, negative correlations were mostly seen between the levels of various forms of the PAs and their biosynthesis/catabolic genes. Levels of different PA forms had a twofold higher negative correlation during drought as compared to salinity stress (66 vs. 32) and with transcript levels of PA biosynthesis and catabolic genes. Transcripts of light-harvesting chlorophyll a/b-binding genes were generally positively associated with different forms of PAs but negatively to carbon flow genes. Most of the PA biosynthesis genes were coordinately regulated under both stresses. Collectively, these results indicate that PAs are distinctly regulated under drought and salinity stress with different but specific homologs of PA biosynthesis and catabolic genes contributing to the accumulation of free, conjugated, and bound forms of PAs.

Conjugated Polyamines in Root Plasma Membrane Enhanced the Tolerance of Plum Seedling to Osmotic Stress by Stabilizing Membrane Structure and Therefore Elevating H+-ATPase Activity

“…Some previous studies have suggested that Put build-up could cause the injury induced by drought stress ( Pedrol et al, 2000 ) and other abiotic stresses ( Slocum, 1991 ; Rodriguez et al, 2001 ). Nevertheless, recent researches showed that the application of exogenous Put could enhance the tolerance of plants to drought stress ( Ebeed et al, 2017 ; Hassan et al, 2020 ; Upadhyay et al, 2021 ) and chilling stress ( Ahmad and Ali, 2019 ). Therefore, in the resistance of plants to environmental stresses, the precise significance of putrescine is still not clear.…”

Metabolome and transcriptome integration reveals insights into the process of delayed petal abscission in rose by STS

“…Polyamines regulate ethylene biosynthesis in relation to nitric oxide (NO) and hydrogen peroxide (H 2 O 2 ) during fruit abscission ( Parra-Lobato and Gomez-Jimenez, 2011 ; Gil-Amado and Gomez-Jimenez, 2012 ). The gene PAO4 is negatively correlated with salt stress and drought stress in tomato ( Upadhyay et al., 2021 ). The expression of ZmPAO2 , 3 , 4 , 5 , and 6 is increased in maize under drought stress ( Pakdel et al., 2020 ).…”

Drought, Low Nitrogen Stress, and Ultraviolet-B Radiation Effects on Growth, Development, and Physiology of Sweetpotato Cultivars during Early Season

“…In the field, the occurrence of single-stress conditions is rare. Combined stress factors at the early vegetative stage affect several morphological, physiological, and biochemical processes in the plants, such as plant vigor, plant growth rate, assimilate partitioning, photosynthesis, stomatal conductance, translocation, leaf nitrogen, sink strength, and nutrient metabolism [ 15 , 31 , 32 , 33 , 34 , 35 ]. Recent studies reported that early-season abiotic stress determines root initiation, and mid- and late-season stresses determine biomass and yield in sweetpotatoes [ 13 , 36 ].…”