Evaluation of Dittrichia viscosa aquaporin Nip1.1 gene as marker for
arsenic tolerant plant selection
Abstract
Dittrichia viscosa (L.) Greuter is gaining attention for its high
genetic plasticity and ability to adapt to adverse environmental
conditions including heavy metals and metalloids pollution. Uptake and
translocation of cadmium, copper, iron, nickel, lead, and zinc to the
shoots have been characterized but its performance with arsenic is less
known and sometimes contradictory. Tolerance to As is not related to a
reduced uptake but the null mutation of the aquaporin Nip1.1 gene
in Arabidopsis, makes the plant completely resistant to the metalloid.
This aquaporin, localized in the Endoplasmic Reticulum is responsible
for arsenite and antimony (Sb) membrane permeation but the uptake of
arsenite occurs also in the null mutant, suggesting a more sophisticated
action mechanism than direct uptake. The DvNIP1 gene homologue is here
cloned and its expression profile in roots and shoots is characterized
in different arsenic stress conditions. The use of clonal lines allowed
to evidence that DvNip1.1 expression level is influenced by
arsenic stress. The proportion of gene expression in roots and shoots
can be used to generate an index that appears to be a promising putative
selection marker to predict arsenic-resistant lines of Dittrichia
viscosa plants.