Ammonium and nitrate affect sexually different responses to salt stress in Populus cathayana

Abstract

Nitrogen (N) fertilization is a promising approach to improve salt tolerance. However, it is poorly known how plant sex and inorganic N alter salt stress-induced Na + uptake, distribution and tolerance. This study employed Populus cathayana Rehder females and males to examine sex-related mechanisms of salt tolerance under nitrate (NO 3 À ) and ammonium (NH 4 + ) nutrition. Males had a higher root Na + efflux, lower root-to-shoot translocation of Na + , and higher K + /Na + , which enhanced salt tolerance under both N forms compared to females. On the other hand, decreased root Na + efflux and K + retention, and an increased ratio of Na + in leaves relative to shoots in females caused greater salt sensitivity. Females receiving NH 4 + rather than NO 3 À had greater net root Na + uptake, K + efflux, and translocation to the shoots, especially in leaves. In contrast, males receiving NO 3 À rather than NH 4 + had increased Na + translocation to the shoots, especially in the bark, which may narrow the difference in leaf damage by salt stress between N forms despite a higher shoot Na + accumulation and lower root Na + efflux. Genes related to cell wall synthesis, K + and Na + transporters, and denaturized protein scavenging in the barks showed differential expression between females and males in response to salt stress under both N forms. These results suggested that the regulation of N forms in salt stress tolerance was sex-dependent, which was related to the maintenance of the K + /Na + ratio in tissues, the ability of Na + translocation to the shoots, and the transcriptional regulation of bark cell wall and proteolysis profiles. | INTRODUCTIONA high concentration of salt in soil is an important environmental stress factor, which affects sex ratios, spatial segregation, and competitive relations of males and females (Che-Castaldo et al., 2015;Li et al., 2016;Varga & Kytöviita, 2012). Therefore, it is extremely important to discover sexually different response mechanisms to salt stress. Plants have evolved a series of mechanisms to enhance salt tolerance, such as the regulation of osmotic stress, maintenance of K + / Na + , and enhancement of antioxidation (Chakraborty et al., 2016;

Editing Metabolism, Sex, and Microbiome: How Can We Help Poplar Resist Pathogens?

“…Male individuals respond faster to salt stress in the presence of nitrogen, as suggested by the results of the differential expression assessment of multiple genes [303]. But under salt stress, for example, the expression of genes related to isoprenoid biosynthesis was elevated in female individuals [304]. Looking at the effects on poplar defense mechanisms, the representation of pipecolic and N-hydroxypipecolic acids increased, and SA and jasmonoyl isoleucine decreased in xylem sap when nitrogen availability increased; a number of secondary metabolites (salicinoids, phenylpropanoids, phenolic compounds, flavonoids and benzoates), with the exception of coumarins, were more actively synthesized under nitrogen deficiency [305].…”

Sustaining nitrogen dynamics: A critical aspect for improving salt tolerance in plants

“…+ assimilation (Liu et al, 2022). NH 4 + can also be assimilated by glutamate dehydrogenase (GDH), which converts aoxoglutarate to glutamate.…”

“…Research focus on sustaining N dynamics in managing salt stress responses gained attention. Salt stress has an impact on nitrification and ammonification in the soil as chloride (Cl -) competes with nitrate (NO 3 -) and causes ion toxicities and ionic disparities, which can explicitly restrict N uptake, transport and assimilation processes (Campbell, 1999;Zhao et al, 2020;Liu et al, 2022;Tzortzakis et al, 2022, Figure 1). Reductions in N uptake and metabolism have been reported in many plant species (Dalio et al, 2013;Singh et al, 2016;Shahzad et al, 2017;Fuertes-Mendizabal et al, 2020, Table 1).…”

Sex-specific competition differently regulates the response of the rhizosphere fungal community of Hippophae rhamnoides–A dioecious plant, under Mn stress

“…Xia et al (2020) showed that male P. cathayana had higher tolerance than female plants under low phosphorus nutrient stress by enhancing symbiosis with mycorrhizal fungi. Under the salt stress, the addition of ammonium and nitrate nitrogen promoted male P. cathayana efflux Na + ions through the roots, and fewer Na + ions were transferred to the shoot, which makes male plants have a higher salt tolerance than female plants (Liu et al, 2022b).…”

“…Under the salt stress, the addition of ammonium and nitrate nitrogen promoted male P . cathayana efflux Na + ions through the roots, and fewer Na + ions were transferred to the shoot, which makes male plants have a higher salt tolerance than female plants ( Liu et al, 2022b ).…”