GTPase ROP6 negatively modulates phosphate deficiency through inhibition of PHT1;1 and PHT1;4 in Arabidopsis thaliana

Abstract

Phosphorus, an essential macroelement for plant growth and development, is a major limiting factor for sustainable crop yield. The Rho of plant (ROP) GTPase is involved in regulating multiple signal transduction processes in plants, but potentially including the phosphate deficiency signaling pathway remains unknown. Here, we identified that the rop6 mutant exhibited a dramatic tolerant phenotype under Pi-deficient conditions, with higher phosphate accumulation and lower anthocyanin content. In contrast, the rop6 mutant was more sensitive to arsenate (As(V)) toxicity, the analog of Pi. Immunoblot analysis displayed that the ROP6 protein was rapidly degraded through ubiquitin/26S proteasome pathway under Pideficient conditions. In addition, pull-down assay using GST-RIC1 demonstrated that the ROP6 activity was decreased obviously under Pi-deficient conditions. Strikingly, protein-protein interaction and two-voltage clamping assays demonstrated that ROP6 physically interacted with and inhibited the key phosphate uptake transporters PHT1;1 and PHT1;4 in vitro and in vivo. Moreover, genetic analysis showed that ROP6 functioned upstream of PHT1;1 and PHT1;4. Thus, we conclude that GTPase ROP6 modulates the uptake of phosphate by inhibiting the activities of PHT1;1 and PHT1;4 in Arabidopsis.

Brassinosteroid transcription factor BES1 modulates nitrate deficiency by promoting NRT2.1 and NRT2.2 transcription in Arabidopsis

“…The methods of immunoblot assays were introduced previously (Gao et al., 2021). 10‐day‐old 35S::BES1‐FLAG , pBZR1::BZR1‐GFP and Col‐0 seedlings pre‐grown under 2.5 m m nitrate conditions prepared for total protein extraction.…”

Systematic Identification and Expression Analysis of the Sorghum Pht1 Gene Family Reveals Several New Members Encoding High-Affinity Phosphate Transporters

“…Pht1 is, therefore, regarded as the most important carrier for P from the soil in low-P conditions. Consequently, considerable focus has been placed on Pht1 family genes in recent years, which has resulted in their identification and functional analysis in an eclectic array of plant species, such as Arabidopsis thaliana [14][15][16], Solanum lycopersicum [17][18][19], Medicago truncatula [20,21], Solanum tuberosum [22,23], Oryza sativa [24,25], Zea mays [26], Triticum aestivum [27,28], Setaria italica [29], and Glycine max [30].…”