3 research outputs found
Effects of Deficiency and Excess of Zinc on Morphophysiological Traits and Spatiotemporal Regulation of Zinc-Responsive Genes Reveal Incidence of Cross Talk between Micro- and Macronutrients
Zinc
(Zn) is an essential micronutrient which affects plant growth
and development in deficiency and can be toxic when present in excess.
In Arabidopsis thaliana, different
families of cation transporters play pivotal roles in Zn homeostasis.
In the present study, we evaluated the effects of Zn in its deficiency
(0 μM; Zn−) and excess (75 μM; Zn++) on various
morphophysiological and molecular traits. Primary root length was
reduced in Zn– seedlings, whereas there were significant increases
in the number and length of lateral roots under Zn– and Zn++
conditions, respectively. Concentration of various macro- and microelements
showed variations under different Zn regimes and notable among them
was the reduced level of iron (Fe) in Zn++ seedlings compared to Zn+.
Certain members of the ZIP family (<i>ZIP4</i>,<i> ZIP9</i>, and <i>ZIP12</i>) showed significant induction in roots
and shoots of the Zn– seedlings. Their suppression under Zn++
condition indicated their transcriptional regulation by Zn and their
roles in the maintenance of its homeostasis. Zn-deficiency-mediated
induction of <i>HMA2</i> in roots and shoots suggested its
role in effluxing Zn into xylem for long-distance transport. Attenuation
in the expression of Fe-responsive <i>FRO2</i> and <i>IRT1</i> in Zn– roots and their induction in Zn++ roots
provided empirical evidence toward the prevalence of a cross talk
between Zn and Fe homeostasis. Variable effects of Zn– and
Zn++ on the expression of subset of genes involved in the homeostasis
of phosphate (Pi), potassium (K), and sulfur (S) further highlighted
the prevalence of cross talk between the sensing and signaling cascades
of Zn and macronutrients. Further, the inducibility of <i>ZIP4</i> and <i>ZIP12</i> in response to cadmium (cd) treatment
could be harnessed by tailoring them in homologous or heterologous
plant system for removing pollutant toxic heavy metals from the environment