Effects of 17<i>β</i>-Estradiol on Growth, Primary Metabolism, Phenylpropanoid-Flavonoid Pathways and Pathogen Resistance in <i>Arabidopsis thaliana</i>

Abstract

Mammalian sex hormones are spread in the environment from natural and anthropogenic sources. In the present study, the effect of estradiol on Arabidopsis thaliana growth primary metabolism, phenylpropanoid and flavonoid pathways and pathogen resistance were investigated. Treatments of Arabidopsis plants with 10 and 100 nM 17β-estradiol resulted in enhanced root growth and shoot biomass. In addition, treated plants had an increased rate of photosynthesis with a concomitant increase in carbohydrate and protein accumulation. Plants exposed to higher concentrations of 17β-estradiol (10 μM) had significantly lower root growth, biomass, photosynthesis rate, primary metabolite and phenylpropanoid and flavonoid contents indicating a toxic effect of estradiol. Treatments with increasing estradiol concentrations (10 nM, 100 nM and 10 μM) resulted in the downregulation of phenylpropanoid-flavonoid pathway genes (PAL1, PAL4, CHI and ANS) and subsequent decreased accumulation of phenolics, flavonoids and anthocyanins. Estradiol-treated plants were inoculated with Pseudomonas syringae pv. Tomato DC3000 and basal resistance was determined. Estradiol treatments rendered plants susceptible to the pathogen, thus compromising the plant defense mechanisms. These results indicate that at low concentrations, estradiol functions as a biostimulant of growth, yield and primary metabolism of Arabidopsis. However, estradiol functions as a potential transcriptional regulator of the phenylpropanoid pathway genes in Arabidopsis, having a negative effect on the phenylpropanoid and flavonoid biosynthetic pathways.

Uptake and transformation of steroid estrogens as emerging contaminants influence plant development

“…affected by a high treatment with estrogens. These findings are in agreement with previous results that have shown a reduction of chlorophyll content in A. thaliana at 2704 µg L -1 and stimulation of carotenoids in Wolffia arrhiza (Lemnaceae) (at 10 -6 M) in response to 17β-E2 exposure (Czerpak and Szamrej, 2003a;Upadhyay and Maier, 2016b). Similar findings of a decline in photosynthesis with synthetic estrogen (EE2) contamination were reported in green alga Chlamydomonas reinhardtii and Dunaliella salina at 1893 µg L -1 and 100 ng L -1 (Pocock and Falk, 2014;Belhaj et al, 2017).…”

“…5.4). However interestingly, at the 0.1 µg L -1 treatment improve the root length, which is in agreement with results obtained with other plant species such as A. thaliana (Upadhyay and Maier, 2016b), and chickpea (Erdal and Dumlupinar, 2011b). However, at doses higher than 50 µg L -1 , there was an inhibitory effect on root morphology.…”

“…However, at doses higher than 50 µg L -1 , there was an inhibitory effect on root morphology. This is in agreement with a significant reduction in root length in response to estrogen exposure at 2704 µg L -1 in Phaseolus aureus L. and A. thaliana (Guan and Roddick, 1988a;Upadhyay and Maier, 2016b).…”

“…We show here that application of 17β-E2 and EE2 concentrations (0.1 and 50 µg L -1 ) has a positive impact on the root growth. Similarly, studies reported that 17β-E2 had induced the growth at low concentration and detrimental effects at high concentration on Medicago sativa and Arabidopsis thaliana (Shore et al, 1992;Upadhyay and Maier, 2016b). The positive effect at low concentration may be caused by hormesis.…”

Removal and Biodegradation of 17β-Estradiol and Diethylstilbestrol by the Freshwater Microalgae Raphidocelis subcapitata

“…Additionally, it has been reported that E2 can improve antioxidative enzyme activities and avoid H 2 O 2 generation to reduce oxidative stress injury from heavy metal induced [ 41 ]. Furthermore, E2 can also disturb the expression of phenylpropanoid-flavonoid pathway genes and decrease the accumulation of phenols, flavonoids, and anthocyanins of plant cells [ 42 ]. For microalgae, there are also several mechanisms to protect themselves from the toxicity of contaminants [ 43 ].…”