Conservation and divergence of both phosphate‐ and mycorrhiza‐regulated physiological responses and expression patterns of phosphate transporters in solanaceous species

Abstract

Summary• Here, orthologous genes of six phosphate transporter (PiT) genes, which are members of the Pht1 and Pht2 families in tomato and potato, have been cloned from the solanaceous species pepper, eggplant and tobacco.• Overall, expressions of these genes in pepper, eggplant and tobacco showed similar patterns to those in tomato and potato: P-starvation enhancement in both leaves and roots for Pht1;1 , P-depletion induction exclusively in roots for Pht1;2 , mycorrhizal enhancement for Pht1;3 , and mycorrhizal induction for both Pht1;4 and Pht1;5 .• In the roots of nonmycorrhizal eggplant, SmPht1;3 , SmPht1;4 and SmPht1;5 were also expressed under extreme P starvation. Mycorrhizal symbiosis under high-P supply conditions reduced plant growth, with concurrent enhancement of Pht1;2 expression in the roots of pepper as well as eggplant. In addition, the mycorrhizal symbiosis down-regulated the expression of Pht2;1 genes greatly in the leaves of pepper and tobacco.• The discrepancies between the evolutionary distances of the PiT genes and their expression patterns among the five species suggest greater complexity in function of PiT in plants than previously expected.

A Constitutive Expressed Phosphate Transporter, OsPht1;1, Modulates Phosphate Uptake and Translocation in Phosphate-Replete Rice

“…For the measurement of total P concentration in the plant, the samples were used following the method described by Wang et al (2009) and Chen et al (2007). Briefly, 0.03-g dry samples were predigested in glass tubes with H 2 SO 4 for 2 h. The tubes were then heated to 180°C, and 50 mL of hydrogen peroxide was added every 10 min until the solution turned colorless.…”

“…A large number of the genes that encode PiTs have been identified from different plant families, including Arabidopsis (Arabidopsis thaliana), cereals, legumes, and solanaceous species (Paszkowski, 2006;Bucher, 2007;Chen et al, 2007;Ai et al, 2009;Jia et al, 2011;Nagarajan et al, 2011). A majority of them showed expression either exclusively or predominantly in the roots, and transcript levels were strongly induced by low Pi supply or by inoculation with arbuscular mycorrhiza (Mudge et al, 2002;Paszkowski et al, 2002;Javot et al, 2007;Ai et al, 2009).…”

Structure and Expression Profile of the Phosphate Pht1 Transporter Gene Family in Mycorrhizal Populus trichocarpa

“…LePT3/LePT4 in tomato and StPT3/StPT4 in potato, as well as their orthologs from other solanaceous species; Nagy et al, 2005;Chen et al, 2007) belonging to Pht1 subfamily III and I, respectively, and a single gene or two genes in leguminous (MtPT4 and LjPT3 in M. truncatula and L. japonicus, respectively) and poaceous (OsPT11 and OsPT13 in rice [Oryza sativa] and ZmPT6 in maize) species were also identified Gü imil et al, 2005;Maeda et al, 2006;Nagy et al, 2006). In poplar, PtPT8 and PtPT10, phylogenetically related to the AM-inducible Pht1 genes from subfamily I, are functionally different; only PtPT10 was specifically induced in poplar roots colonized by AM fungi.…”

Closely Related Members of the Medicago truncatula PHT1 Phosphate Transporter Gene Family Encode Phosphate Transporters with Distinct Biochemical Activities

“…Furthermore, the different P i transporter gene families are themselves composed of multiple members (2, 6). Current data suggest that members of the PHT1 P i transporter family mediate transfer of P i into cells, whereas members of the PHT2, PHT3, PHT4, and pPT families are involved in P i transfer across internal cellular membranes and organelle membranes (7-10).Members of the PHT1 P i transporter gene family have been identified from a wide range of plant species including Arabidopsis, rice, Medicago truncatula, and tomato (11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Many of these transporters are expressed in roots and show elevated transcript levels during growth in low P i conditions.…”