Figure 6

L. camara endophyte consortium reduced arsenate, upregulated arsenate reductase activity in As- dependent manner and differentially regulated aquaporin and MRP genes. S. nigrum plants were grown in presence or absence of 25 ppm As, treated with or without the endophytes used as a consortium. (A) Arsenate reductase activity was measured in the root and shoot 4wpi. n = 10 (each in 2 experimental replicates). *P < 0.05, ***P < 0.001 (endophyte- treated vs uninoculated; Two-way ANOVA with Tukey’s post-hoc test). (Df for As:1, for endophytes:1, for interaction:1, error:36). (B) AgNO₃ was added to bacterial cells (live & dead) incubated in Tris-Cl buffer with arsenate for 48 h and the colour was compared to standards having varying As(V)/As(III) ratio. Viability of live cells was measured. LC1.:Enterobacter sp. LC1, LC2.:Kocuria sp. LC2, LC3.:Kocuria sp. LC3, LC4.:Enterobacter sp. LC4, LC5.:Kocuria sp. LC5, LC6.:Enterobacter sp. LC6, LC7.:Kosakonia sp. LC7., Mix: Consortium, U: uninoculated control. (C) As(V) and As(III) speciation was performed in S. nigrum shoot extracts grown in the presence or absence of the consortium. As(V) and As(III) was separated using calcium alginate beads followed by ICP-OES. Results have been represented as pie charts showing the percentage of each species in the total As. n = 6. (D) cDNA was prepared from root and shoot of 4-week infected plants and expression of 4 aquaporins and 3 MRP transporters in root and shoot were measured by real-time PCR. The fold change of expression has been normalized to that of control. SnTIP2-1, SnATIP and SnTIP2-2 = Tonoplast intrinsic proteins; SnPIP1 = Plasma membrane intrinsic protein; SnMRP1, SnMRP2 and SnMRP3 = Multidrug resistance-associated proteins. *P < 0.05,**P < 0.01,***P < 0.001. Data are represented as mean ± SEM.