Sulfur transfer from the endophytic fungus Serendipita indica improves maize growth and requires the sulfate transporter SiSulT

Abstract

A deficiency of the essential macronutrient sulfur leads to stunted plant growth and yield loss; however, an association with a symbiotic fungus can greatly improve nutrient uptake by the host plant. Here, we identified and functionally characterized a high-affinity sulfate transporter from the endophytic fungus Serendipita indica. SiSulT fulfills all the criteria expected of a functional sulfate transporter responding to sulfur limitation: SiSulT expression was induced when S. indica was grown under low-sulfate conditions, and heterologous expression of SiSulT complemented a yeast mutant lacking sulfate transport. We generated a knockdown strain of SiSulT by RNA interference to investigate the consequences of the partial loss of this transporter for the fungus and the host plant (maize, Zea mays) during colonization. Wild-type S. indica, but not the knockdown strain (kd-SiSulT), largely compensated for low sulfate availability and supported plant growth. Colonization by wild-type S. indica also allowed maize roots to allocate precious resources away from sulfate assimilation under low-sulfur conditions, as evidenced by the reduction in expression of most sulfate assimilation genes. Our study illustrates the utility of the endophyte S. indica in sulfur nutrition research and offers potential avenues for agronomically sound amelioration of plant growth in low-sulfate environments.

Genome-Wide Identification of Sultr Genes in Malus domestica and Low Sulfur-Induced MhSultr3;1a to Increase Cysteine-Improving Growth

“…These results suggest that Sultr exhibits species specificity. Moreover, several studies confirmed that the overexpression of Sultr genes could improve plant growth under low-S conditions by upregulating the genes involved in the S assimilation pathway and promoting the biosynthesis of essential amino acids and S-containing compounds (Ding et al, 2016;Narayan et al, 2021). In our study, under low-S conditions, the overexpression of MhSultr3;1a in apple calli resulted in better growth (Figure 7C) and higher fresh weight (Figure 7D).…”

Metal transporters in organelles and their roles in heavy metal transportation and sequestration mechanisms in plants

“…Metal uptake from soil or mobilization to other plant parts involves different transporters localized at the plasma membrane and envelope membranes of cell organelles such as the vacuole, mitochondria, and plastids. Notably, plants have a sensing system for maintaining metal homeostasis in which transporters work as receptors plus transporter, that is, transceptors (Cointry & Vert, 2019; Narayan et al 2020; Narayan et al, 2021; Yadav et al, 2021b). The bioavailability of metal ions in soil and their scarcity in the cytosol can be sensed by transceptors, which leads to the regulation of metal ions uptake via low or high‐affinity transporters.…”

Regulation of Tomato Specialised Metabolism after Establishment of Symbiosis with the Endophytic Fungus Serendipita indica

“…The root endophyte Serendipita indica (formerly known as Piriformospora indica, order Sebacinales, phylum Basidiomycota) has been extensively used in studying plant-fungal interactions [14][15][16]. S. indica is an axenically cultivable fungus, able to colonise a wide range of plant species.…”